CA1115551A - Process for packing chromatographic columns - Google Patents
Process for packing chromatographic columnsInfo
- Publication number
- CA1115551A CA1115551A CA308,074A CA308074A CA1115551A CA 1115551 A CA1115551 A CA 1115551A CA 308074 A CA308074 A CA 308074A CA 1115551 A CA1115551 A CA 1115551A
- Authority
- CA
- Canada
- Prior art keywords
- column
- pressure differential
- packing material
- packing
- regular periodic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
- G01N30/50—Conditioning of the sorbent material or stationary liquid
- G01N30/56—Packing methods or coating methods
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D15/00—Separating processes involving the treatment of liquids with solid sorbents; Apparatus therefor
- B01D15/08—Selective adsorption, e.g. chromatography
- B01D15/10—Selective adsorption, e.g. chromatography characterised by constructional or operational features
- B01D15/20—Selective adsorption, e.g. chromatography characterised by constructional or operational features relating to the conditioning of the sorbent material
- B01D15/206—Packing or coating
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
- G01N30/50—Conditioning of the sorbent material or stationary liquid
- G01N30/56—Packing methods or coating methods
- G01N2030/562—Packing methods or coating methods packing
Abstract
ABSTRACT OF THE DISCLOSURE
This invention relates to chromatographic columns and particularly to a method of packing a chromatographic column which is characterized by the steps of introducing a packing material into a chromatographic column under the influence of a first pressure differential and in the substantial absence of substantially regular periodic vibration until said chromatographic column is filled to a desired extent with said packing material, and subsequently establishing a substantially regular periodic vibration along the length of said column and subjecting said packing material to a second pressure differential.
This invention relates to chromatographic columns and particularly to a method of packing a chromatographic column which is characterized by the steps of introducing a packing material into a chromatographic column under the influence of a first pressure differential and in the substantial absence of substantially regular periodic vibration until said chromatographic column is filled to a desired extent with said packing material, and subsequently establishing a substantially regular periodic vibration along the length of said column and subjecting said packing material to a second pressure differential.
Description
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The present invention relates to chromatography. More particularly, the present invention relates to methods for packing chromatographic columns with a particulate packing material.
Chromatography, in all its forms, is a technique used to separate a mixture of compounds or elements into their individual components. All chromatographic processes con-sist of two basic segments: a mobile phase and an immobile phase. The mobile phase moves through a capillary or tube, called a column, containing the imrnobile phase, and the sample to be separated into its basic components is injected into the mobile phase moving through the column. As the sample is swept forward by the mobile phase, the sample components are either adsorbed on the surace of the immobile phase (if the immobile phase is a solid), or dissolved in the immobile phase (if it is a liquid). As the mobile phase continues passing through the column, components of the sample are continuously desorbed back into the mobile phase.
This adsorption-desorption process continues throughout the length of the column, each sample component in the mobile phase thus moving through the column at a different rate, depending primarily upon its attraction for the immobile phase. The components therefore separate as they pass through the column and emerge at the other end of the column at different times.
In liquid chromatography, the sample which is to be analyzed is a combination of liquid components which are car-ried through the column in the liquid phase by a mobile phase comprising a liquid carrier stream. The immobile phase in :`
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liquid chromatography generally comprises a solid in the form `of uniform or other particles packed in the column.
In gas chromatography, the sample to be analyzed comprises volatile components which are carried through the column in a gaseous state by an inert mobile phase called the carrier gas.
The immobile phase is a solid in the form of uni~orm or other particles, and/or a thin film on either the particles and/or the column walls.
-Under proper gas chromatographic conditions, various components of th~ gas sample are spacially separated by the above-described process of selective adsorption and desorption, so that the separated gas constituents issue from the end of the column in sequential order corresponding to their relative volatility, their molecular weight, or some other property af- ;
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fecting the degree o~ adsorption on the immobile phase or packing material in the column. As these separated gases emerge ~rom the column, they are normally passed through a suitable detector element which measures a property of the gas indicative of the ;~
character and/or amount present.
The immobile phase or packing most commonly used in chromatographic columns includes diatomaceous earth, alumina, glass beads, fluoro carbons, silica gel, and the like. Conventionally, the packing in whatever form is chosen for a particular chromatographic column, is poured into the column in granular form~ and is compacted therein by vibration, tamping or the like. To operate the gas chromatographic columns, an inert gas, such as helium, argon or nitrogen, acts as the carrier gas for the sample and flows continuously through the column.
The use of such an inert mobile carrier gas insures that it does not react with either the sample or the immobile phase. The samples are introduced into the carrier ~as either as a liquid or a gas. Usually, liquid samples on the order of ten micro- -liters or less are injected rapidly into a chamber which is maintained at a temperature that insures quick and complete vaporization o~ the sample.
The efficiency of these columns determines the length o~ time it takes in order to perform a given analysis. ~olumns having high e~ficiencies can be of shorter length than columns having low eficiencies and, with the carrier gas flowing at the same rate, the analysis can be performed much more readily in the more efficient column. It is desirable to improve the efficiency of a column for two principal reasons. A column of high efficiency can perform an analysis much more rapidly, and a column with high efficiency will have a greater ability to separate two sample components (or to resolve them), and ~;
hence the capability of analyzing products more pxacisely than will a column of lesser efficiency having an equivalent length.
The efficiency of chromatographic columns is generally expressed in terms of theoretical plates, which is simply a number of theoretical plates per unit of length necessary to effect resolution. As a component in a sample is moved through the column by a carrier gas, the velocity at which the component is traveling, the dimenslons of the column, the medium through which it travelsl and the packing density will have a direct influence on the column efficiency. As the packing density increases, however, there is a commensurate and undesirable pressure drop increase across the packed portion of the column.
Many techniques have heretofore been developed for pack-ing chromatographic columnsu Thus, for example, U.S. Patent Nos. 2,~45,136 and 3,164,980 each describe packing techniques wherein the packing material is poured into the chromatographic column and compacted therein by vibration, tamping or the like. U.S. Patent Nos. 3,248,856; 3,522,172; 3,692,669 and 3,796,657 disclose packing techniques wherein the packing medium is fluidized by various techniques and then allowed to settle to form a packed bed. In "GAS CHROMATOGRAPHY 1960"
edited by R.P.W. Scott, published by sutterworths (London) at pages 240 et seg., the effect on packing structure of various modes of vibration, tapping, rotations, or combinations thereof is disclosed.
"A STUDY OF PACKED CAPILLARY COLUMNS," by V. G. Berezkin et al., Journal o Chromatography, 99 (1974) pages 111-112, discloses the packing o columns by simply tapping the packed column lightly by hand, or by moving a mechanical vibrator along the column. The authors also disclose the filling and packing of such columns utilizing a combination of an inert gas flow and low-frequency (50-100 Hz) electromechanical vibrators located at several positions along the column.
In "PERMEABILITY AND PREPARATION OF MICRO-PACKED COLUMNS,"
By J. A. Rijks et al., Chromatoyraphia, Volumn 8, No. 9, -September, 1975, pages 482 et seg., the authors disclose simultaneously filling and packing a micropacked column (i.e.
having a particle/column diameter rate between 0.1 and 0.3) with the use of ~radually increasing pressure and ultrasonic vibrations. The authors also disclose t~at a hand vibratox held on the surface of the container is employed to assist in provid~
ing a continuous stream of particles to the column.
Finally, in "POTENTIALITIES OF MICROPACKED COLUMNS SO~E AP-PL~CATIONS IN PETROLEUM CHEMISTRY," C. A. Cramers, J. Rijks and P. Bocek, ~. Chromatography, 65 (1972) 2937, a continuation of ultrasonic vibration and pressure is employed to simultaneously fill and pack a chromatographic column. This article also ::~
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notes that at the start of the procedure the pressurP increase shall be very gradual, and notes that care should be taken to maintain a substantially constant pressure product across the packing to ensure a homogeneous packing density.
Despite -the many techniques currently available, all of which employ various combinations of pressure and vibration, those skilled in the art still recognize the need for a packing technique which will maximize packing density while still im-posing a relatively low pressure drop across the packed portion of the column.
According to an embodiment of the present invention, there is provided a method of packing a chromatographic column, characterized by the steps of introducing a packing material into a chromatographic column under the influence of a first pressure differential and in the substantial absence of sub-stantially regular periodic vibration until said chromatographic column is filled to a desired extent with said packing material, and subsequently establishing a substantially regular periodic vibration along the length of said column and subjecting said packing material to a second pressure differential.
In a preferred embodiment of the present invention, the second pressure differential is greater than the first pressure differential, and preferably the substantially regular periodic vibrations along the length of the column comprise ultrasonic -~
vibrations, preferably produced by immersing the column in a bath of liquid and subjecting that liquid both to ultrasonic vi-brations. In another embodiment of the present invention, the first and second pressure differentials are maintained by intro-ducing a fluid such as an inert gas stream into the column, and preferably also by applying a vacuum ~o the end of the column.
In another embodiment of the present invention, any s~a-tic _ 5 _ ~11 5S5~L
charge on the packing material is reduced. For example, where an inert gas stream is utilized, the gas stream may be passed into contact with a radiation source prior to its entry into the column, or in another embodiment, the particles in the column are heated for that purpose.
In a preferred embodiment of the present invention where an inert gas stream is used to produce the first pressure differential, the column is purged of inert gas prior to esta-blishing the substantially regular periodic vibrations along the lengths of the column thereafter. Most preferably the column is subjected to the second pressure differential immediately after the establishment of the substantially regular periodic vibra-tion alony the length of the column, preferably comprising ultrasonic vibrations.
In yet another embodiment of the present invention, the second pressure differential is established substantially in-stantaneously, and in another embodiment irregular vibrations are applied to the column during the introduction of the packing material under the influence of the first pressure difEerential.
Those irregular vibrations can preferably be produced by tapping on the column itself.
In still another embodiment of the present invention, a plurality of steps are employed in connection with the intro-duction of the packing material into the column under the in-fluence of the first pressure dif~erential, with a portion of the packing material being introduced into the column in each of those steps. Preferably, irregular vibrations are applied to the column during each of those steps. Finally, the present invention comprises chromatographic columns packed in accordance with any of the foregoing methods.
In order that the invention may be fully understood, .. :
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embodiments of the invention will now be described with reference to the accompanying drawings, in which:
Flgure l is a schematic diagram illustrating an appa-ratus in which the method for packing a chromatographic column in accordance with an embodiment of the present invention can be effected; and Figure 2 is a schematic diagram illustrating an appa-ratus for effecting the method of an embodiment of the present invention used in conjunction with a monolithic glass chromato-graphic column.
The method of the present invention can be applied to a variety of chromatographic columns employing a variety of packing material therein. The columns can include glass and metallic columns, and can include columns generally referred to as micro-bore columns (i.e. generally having an inside diameter of be~
tween about .7 and 1.2 millimeters), and macrobore columns (i.e.
those having inside diameters greater than about 1.2 millimeters).
This technigue can also be applied to such columns wsed for both liquid and gas chromatographic purposes.
While a variety of packing materials can be utilized in connection with the methods hexeof, it must be borne in mind that certain types of packing materials will not be susceptible to the techniques of the present invention. That is, they cannot be packed more efficiently in accordance with the present inven-tion and achieve the improved results which are possible there-with. It is thus necessary that the packing material utilized have a sufficiently low friability or high crush strength during packing so as to avoid crushing or disintegration during packing under the conditions employed herein. If the materials utilized cannot maintain a substantial degree of their physical character-istics during packing, including the application of vibrations ~: :
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and pressures in accordance with this method, then the improved results achievable in accordance herewith cannot be realized with such packing materials.
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B~aring Ll~.is in mind, Lhe packi.ncJ m~lerials which ~arl ~e emL~loyed in co~ ection with the present invel~tion include a nu~ r of converltional chromatographic packing materials, generally conl~)risill(3 inert solids such as diatomaceous earth, alumina, glass beads, TeElon beads, graphitized carbon bl~lck, molecular sieves, silica yel (generally used in conjunction with high-pressure liquid chromatography) and the like. These inert packings of support materials are preferably of uniform par~lcle size and will generally range from about S to about 200 microns in particle size.
ReEerring to the figures, in which li.ke numerals refer -to like portions thereof, Figure 1 shows an apparatus for packing a conventional chromatographic column such as a convent.ional c~lass spiral colum~ 10 which is immersed in a water ba~h 12. The water bath can be made to cavitate by imparting ul-trasonic vibration~
thereto in a conventional manner. The effluent line 14 from the column leads to a vacuum pump (not shown), while the inlet line 16 to the column is connected to a reservoir 18 which con-tains the colu~ packing ma~erial. The reservoi.r 18, in turn, is connected to an iner~- gas feed line 20. Of course, where a liquid is to be utilized instead of the inert gas, such as ~or packing a ~olumn for use in high pressure liquid chromatography, analogous apparatus for applying such a liquid will be employed.
In instances wherein the packing material has been deactivated, e.g. ~herein the particles are treated with a silanizin~
reagerlt, the inert gas can be fed to the reservoi.r 18 through a line 22 whereby the inert gas is exposed to a radioactive sour(e 24 which expels ions in-to the gas stream for static elimil-ation pur~oses. The inert gas can be Eed directly i.nto the reservoir 18 via line 20 by closing valve 26 and opening valve 28. ~onversely, wherl i.t is desired to pass the i.nert gas * A trade mark through the radioactive source 24 and into the reservoir via line 22, valve 26 can be opened and valve 28 shut.
Before commencing the packing procedure of the present in-vention, it is generally necessary to first prepare the packing material therefor. Thus, for example, for most gas-liquid chromatography applications, it is generally considered preferable to pretreat the inert support materials to impart a silane coat-ing thereto. This ~s conventionally effected by reacting surface silanol groups with organic silane compositions, e.g. dimethyl-dichlorosilane. In any event, however, the particles are first pretreated to remove generally inorganic surface impurities from the support material by washing that material with acid.
Preferably the material is then treated to neutralize the acid and then dried.
In the case o~ gas chromatography, the inert support materials ;
can then be coated with a stationary liquid phase. Nearly any ~ `
unreactive non-volatile liquid can be used as the stationary phase. As a general rule, the boiling or decomposition point o~ ;
this liquid should be substantially above the column operating temperature in order to minimize its gradual vaporization. These stationary liquids can be divided into two groups: that is, those used in separations based upon non-selective columns, i.e.
where the separations are mainly due to differences in vapor pressures or diffusion rates of the components, (these liquids include silicon oils, greases and the like), and those used in separations based upon selective columns where there is a pre~er-red interaction of components with the stationary liquid phase based upon complementary chemical structures, ~these liquids include esters, alcohols, acids, amines and the like).
Typical stationary liquid phases include mineral oil, di- "
octyl phthalate, di-nonyl phthalate, silicone, methyl silicone, nitrobenzene, tricresyl phosphate/ dibutyl phthalate and the like. Particularly where the support material is porous in nature, it is preferable to degas the system after pouring the liquid over the support in order to assist the liquid in enter-ing the pores of this support material. Once the support or packing materials are coated with the stationary phase, they can then be filtered and dried, preferably with nitrogen, in order to remove any solvent therefromu The support can then be loaded into reservoir 18, and the packing procedure is ready to commence.
A chromatographically and chemically inert porous retainer is inserted into the terminal portion of the column proximate the junction of the column passageway with the outlet 14 in order to prevent loss of the packing material. Such retainers can be formed of fiber glass, glass wool, glass frits, an inert metal fiber, or wool such as gold wool and the like. Such retainers can eventually be interposed in the terminal portions of the inlet and outlet lines leading to and from the column to further protect against loss of packing material.
The chromatographic column 10 is attached to the inlet 16 from the reservoir 18 and the outlet 14 leading to the vacuum pump. It is then immersed in the water 30 contained within the ultrasonic bath 12. The packing apparatus is preferably kept in a room in which humidit~ can be controlled so that packing is effected under dry conditions.
The packing process includes an initial l'soft" packing of the inert support or packing material into the column under a mild pressure differential. Preferably, the column is first flushed with a stream of dry inert gas such as dry nitrogen, ~;
argon and the like. The packing operation is then initiated with the periodic addition of the packing material under the in-fluence of a first pressure differential through the column~
This pressure differential can be established ei-ther by using ~O
an inert gas pressure as discussed above, or preferably by means o~ a vacuum applied to the column, or most preferably by utilizing both such an inert gas pressure and a vacuum. This is conducted in a manner so as not to result in a segregation of the particles in terms of various particle sizes therein.
Preferablyr while maintaining the first pressure differential across the column, separate portions of the packing materials are added to the column, and irregular vibrations can be ap-plied to the column, such as by periodically tapping or rapping ;
reservoir 18, or, as another alternative, cavitating the ultra-sonic bath for short periods, for example, up to about 2 seconds at a time, to achieve similar effects. Such a procedure is carried out in order to remove any blockage which may be present in the column. At the same time, the presence of substantially regular periodic vibration along the length of the column is avoided during this stage of the packing process, such as the avoidance of cavitating the ultrasonic bath for significant periods of time throughout this phase of the packing operation.
In other words, what must be avoided is the establishment of a regular wave form within the column, e.g. sinusoidal, triangular, square, etc., so that random loading of the column is insured to prevent the segregation of particle sizes.
As for the actual pressure differential which is established during this soft packing phase of the method of the present in vention, this will depend somewhat on the type o column and the type of packing being applied therein. Thus, the linear gas velocity achieved by any given flow of fluid or gas through the column will be dependent upon the size of the column bore and the average particle size of the packing matexial. As a specific -~
example (for gas chromatography), with a microbore column having a diameter of between about .7 and 1.2 millimeters, and utilizing particles having an average particle size of between about 5 and 75 microns, preferably between about 37 and 44 microns, a first pressure differential hiyh enough to initiate movement of the particles from the reservoir into the column, such as between about 5 and 50 pounds per s~uare inch differential (psid.) per yard of column length will generally be employed.
On the o~her hand, with a macrobore column having a diameter of above about 1.2 millimeters and utilizing a packing material having an average particle size of between about 50 and 200 microns, preferabl~ between about 74 and 84 microns, a first pressure differential between about 5 and 25 psid per yard of column length will be utilized.
Once the column is filled with the packing material to the extent desired, the pressure differential employed in filling the column is substantially abated. For example r where the fluid is a gas, the vacuum is continued at the column outlet for a short period, e.g. 15 minutes. At this point, ca~itation of the ultrasonic bath can be commenced. The bath will generally cavitage when e~posed to an ultrasonic frequency above about 15 kilohertz. Once ultrasonic vibration is commenced along the length of the column the packing material can then be subjected to a second pressure differential, greater than the first pres-sure differential, and agaln dependent upon the size of the column bore and the average particle si~e of the packing material.
Once again, increased particle size packing material will generally permit the use of lower pressure di~ferentials. Utilizing a flow of inert gas to establish the second pressure di~ferential, the differential is substantially ins-tantaneously produced in the column so as to jolt the packing material previously soft packed in the now vibrating column.
While the use of ultrasonic vibration has been discussed above, the significant factor is that in this second phase a \~ :
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substantially regular periodic vibration is established along the length of the column. While the use of fairly short wave length vibrations such as those comprising a low multiple of the average particle diameter of the packing materials are preferred, it is possible to employ longer wave lengths. It is therefore possible to use sonic vibration therein preferably with higher energies therewith. The significant fact is that there is a substantially constant vibration produced in the bed and the packing particles act like a fluidized bed therein. Preferable frequencies of between about 30 and 60 kilohertz are employed.
This procedure results in a maximization of packing density within the column and the concomitant significant improvements realizable in accordance with the present invention.
This second phase can preferably be continued or a period of between about 5 minutes up to about 10 hours, alth~ugh generally periods of between about 5 minutes and 30 minutes are suf-Eicient.
Again considering the previous discussion with respect to the relationship between the pressure differential utilized and the inside diameter of the col~lmn, as well as the average particle size of the packing material utilized, in a microbore column utilizing packing materials having average particle sizes as described above, generally a pressure differential of between about 50 and 500 psid per yard of column length will be utilized.
On the other hand, with a macrobore column utilizing packing materials having average particle sizes as described above, a pressure differential of between about 25 and 250 psid per yard of column length will be utilized. Generally, the second pressure differential must be sufficient to settle the bed and obtain maximum packing density, but cannot be too great so that the gas velocity within the column is elevated to a point where the particles being utilized tend to immobilize or jam and can-not be sufficiently packed therein.
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After the application of this second pressure differen-tial and substantially regular vibration along the column, the ultrasonic bath is turned off and the fluid pressure is terminated.
Any residual pressure is allowed to reduce to ambient pressure slowly so as to avoid disturbing the packing in the column, and any residual fluid in the system is allowed to slowly bleed off. Thereafter, the pa~ked chromatographic column can be disconnected from lines 14 and 16 and a porous retainer as described hereinabove can be inserted into the initial portion of the continuous passageway of the column proximate the junc-tion of the passageway with the inlet 16 thereby sealing the packing within the passageway of the column.
It has been found that columns packed in the foregoing manner exhibit significantly higher separation efficiencies than have heretofore been obtainable by other known prior art techniques. Moreover, even though the packing density is maximized in accordance with the method of the present lnven-tion, it has been found that the pressure drop across the column is still relatively low. ~he packing technique of the present invention enables the obtaining of significantly greater column efficiencies, for example, with a typical gas chromatography -~
microbore column, column eficiencies of up to about 1,000 plates per foot were previously achievable, but in accordance with the present invention it is possikle to achieve column efficiencies of between about 2~000 and 3,000 plates per foot. On the other hand, with a typical gas chromatography macrobore column it was previously possible to obtain consistent column éfficiencies of between about 200 and 800 plates per foot, while in accordance with the present invention effisiencies of between about 1,000 and 1,500 plates per foot can now be achieved. Again~ however, each o these specific efficiencies relate to the particular ~S~5~
column under consideration, and will vary with the diameter of the column bore, the particles being employed, etc.
~ eferring to Figure 2, another embodiment o~ the present invention is shown wherein a monolithic glass chromatographic column 32 is shown being packed in accordance with the method of the present invention. The monolithic glass chromatographic column has a continuous passageway formed therethrough which can be packed with chromatographic packing material in accordance with the present invention. Quick-connect and disconnect couplings 34 and 36 enable the column to be connected and disconnected from the packing system of the present invention. Moreover, these couplings enable the packed chromatographic column to be readily connected to gas feed and analytical devices.
If it is desired to further eliminate the static charge car-ried by the packing particles, the use of the radiation source 24 can be employed, or alternatively or in combination therewith, the inside diameter of the passayeway through the chromatographic column can be coated with a non-reactive and non-catalytic metal such as gold. This can be done by conventional vacuum metallizing techniques.
With reference to Figure 1, an apparatus as shown therein was utilized wherein the effluent line 14 was connected to a ballast chamber of approximately 6 gallons capacity. The bal-last chamber was then connected to a Precision Scientific Corpora-tion model D-75 vacuum pumpj and a ~hitey ball valve was in-cluded in effluent line 14 in order to permit rapid opening of ;~
the effluent line to the ballast chamber. The ballast chamber was used in order to provide a greater reservoir of vacuum ~or ~ -the system.
The column employed was a 6 foot long glass coil 1/4 inch O.D. by 2 millimeters I.D. configured to fit a Hewlett-Packard `:
5700 yas chrorlldto~Jraph, column confiyuration 5. 'l'l~e re~ervoir 18 corlsisted of a l foot lencJth of 3/8 inch O.U. t)y .280 inch I . D. stainless tube connected to the inlet line 16 by means of a SWAG~:I.OC~ 3/8 inch -to l/4 inch brass reducinc~ couplin-J which had been drilled through to l/4 inch I.D. to pe~nit insertion of the column into the reservoir above the level of the fitting.
The top of the reservoir was fitted with a SWAGELOCK 3/8 inch sin~le-end shut-off quick connect coupling which then connected to a Whitey ball valve 28. In this example, the inert gas was ~ed directly into the reservoir 18 through line 20.
The upstream or high pressure end oE -the Whitey ball valve 28 was connected by rneanS of a SWAGELOCK l/4 inch sin~3le~
end shut-of~ ~luick connect to a supply of nitrogen with a reyu-lator which could control between 0 and 200 psig. 'rhe ultrasonic bath 12. was a BRANSONICS model B-52 bath and the fluid in the bath was water with a small amount of bis(2-ethylhexyl) sulfo-succinate, sodium salt in order to reduce the surEace tension and permit better -transduction of the ultrasonic vibration. The support employed was prepared from 30 to 60 mesh CHROMOSORB G
which was ground and screened to produce a support having a n~rrow ranye particle size of between about 100 and 110 microns, employiny electroformed round holed screens as supplied by Stork America Corporation. The ground support was then washed exhaus-tive]y with 8 N hydrochloric acid until the supernatant had no detectable yellow coloration.
After acid washiny, the support was rinsed with de-ioni~ed water until the supernatant was neutral and there was no detectable clc~udiny of the supernatant due to fines. rrhe support was dried overniyht in a 110~C oven, allowed -to cool, and -the coated wi-th licluid phase. Coatiny was accomL~lished by trans-ferring a weicJhed (~uantity o~ support to a round bot-tom c~round * A trade mark - 16 -joint flask and coverinc~ with a solution of 5'~ CARI~OW~X 20M
in ethylene - 16a -* A trade mark .~. .
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dichloride (wei(~ er volume), in the E~ro~ortion c,t 2milliliter~ of coatirl~ solution to each (Jrarn of su~l-oLt.
'rhe resu1tincJ slurry was tllc~ll degassed by subjectirlg it ~o a vacuum while vibLatinc~ in arl ultrasonic ~ l in ord~r to insure complete penetration of the coatiny solution ;nto the ~ores of the su~~ort. The slurry was transferred to a coarse frit Buchner ~unnel with an additional arnount of coating solu-tion (also in the proportion oE 2 milliliter per gram of sup~
port) used ~s a rinse to effect complete transfer. The slurry w~s then filtered under vacuum un-til the solution ceased to drop freely from the end of the funnel. The damE~ support was then transferred to a fluidized bed drier (~ EE'F' fluidizer manufactured by Applied Science Laboratories) ancd dried by fluidizing with a s-tream of warm nitrogen. Five grams oE the resul-ting packing material was introduced to the reservoir 18, the systesn was reconnected and filling was commenced.
With the valve 28 closed and with the valve between the effluent line 14 and the ballast tan~ also closed, the ballast tank was evacuated. The valve in the effluent line was then opened and the reservoir 18 tapped periodically to assist the flow of the packing material into the column. When the filling process slowed, with 0 psig. on the nitrogen regulator, valve 28 was opened to continue the filling process. Whe~ the filling process again slowed, valve 28 was closed, ~0 psig.
was applied from the nitroc3en regulator, and valv~ 28 was again opened to complete the filling process. With the column full and no visible voids therein, a timer was therl set for 15 minutes durln~ which time the vacuum pum~ was allowed to con-tinue to evacua-te ~as from the column. At the end of this time perio~, the nitrocJen pressure was raised to 80 l~ounds, t~-le ultrc,sonic bath was switclled on~ arld valve ~8 wa~ opened to * A trade mark - 17 -.~ .
begin packing of the column. A timer was set for 10 minutesand packing allowed to continue for this period. The ultra-sonic bath was switched off and valve 28 was then closed and the residual pressure allowed to bleed from the effluent line.
While specific embodiments of the chromatographic column packing method of the present invention have been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore, it is intended that no limitations be placed on the invention except as defined by the scope of the appended claims.
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The present invention relates to chromatography. More particularly, the present invention relates to methods for packing chromatographic columns with a particulate packing material.
Chromatography, in all its forms, is a technique used to separate a mixture of compounds or elements into their individual components. All chromatographic processes con-sist of two basic segments: a mobile phase and an immobile phase. The mobile phase moves through a capillary or tube, called a column, containing the imrnobile phase, and the sample to be separated into its basic components is injected into the mobile phase moving through the column. As the sample is swept forward by the mobile phase, the sample components are either adsorbed on the surace of the immobile phase (if the immobile phase is a solid), or dissolved in the immobile phase (if it is a liquid). As the mobile phase continues passing through the column, components of the sample are continuously desorbed back into the mobile phase.
This adsorption-desorption process continues throughout the length of the column, each sample component in the mobile phase thus moving through the column at a different rate, depending primarily upon its attraction for the immobile phase. The components therefore separate as they pass through the column and emerge at the other end of the column at different times.
In liquid chromatography, the sample which is to be analyzed is a combination of liquid components which are car-ried through the column in the liquid phase by a mobile phase comprising a liquid carrier stream. The immobile phase in :`
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liquid chromatography generally comprises a solid in the form `of uniform or other particles packed in the column.
In gas chromatography, the sample to be analyzed comprises volatile components which are carried through the column in a gaseous state by an inert mobile phase called the carrier gas.
The immobile phase is a solid in the form of uni~orm or other particles, and/or a thin film on either the particles and/or the column walls.
-Under proper gas chromatographic conditions, various components of th~ gas sample are spacially separated by the above-described process of selective adsorption and desorption, so that the separated gas constituents issue from the end of the column in sequential order corresponding to their relative volatility, their molecular weight, or some other property af- ;
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fecting the degree o~ adsorption on the immobile phase or packing material in the column. As these separated gases emerge ~rom the column, they are normally passed through a suitable detector element which measures a property of the gas indicative of the ;~
character and/or amount present.
The immobile phase or packing most commonly used in chromatographic columns includes diatomaceous earth, alumina, glass beads, fluoro carbons, silica gel, and the like. Conventionally, the packing in whatever form is chosen for a particular chromatographic column, is poured into the column in granular form~ and is compacted therein by vibration, tamping or the like. To operate the gas chromatographic columns, an inert gas, such as helium, argon or nitrogen, acts as the carrier gas for the sample and flows continuously through the column.
The use of such an inert mobile carrier gas insures that it does not react with either the sample or the immobile phase. The samples are introduced into the carrier ~as either as a liquid or a gas. Usually, liquid samples on the order of ten micro- -liters or less are injected rapidly into a chamber which is maintained at a temperature that insures quick and complete vaporization o~ the sample.
The efficiency of these columns determines the length o~ time it takes in order to perform a given analysis. ~olumns having high e~ficiencies can be of shorter length than columns having low eficiencies and, with the carrier gas flowing at the same rate, the analysis can be performed much more readily in the more efficient column. It is desirable to improve the efficiency of a column for two principal reasons. A column of high efficiency can perform an analysis much more rapidly, and a column with high efficiency will have a greater ability to separate two sample components (or to resolve them), and ~;
hence the capability of analyzing products more pxacisely than will a column of lesser efficiency having an equivalent length.
The efficiency of chromatographic columns is generally expressed in terms of theoretical plates, which is simply a number of theoretical plates per unit of length necessary to effect resolution. As a component in a sample is moved through the column by a carrier gas, the velocity at which the component is traveling, the dimenslons of the column, the medium through which it travelsl and the packing density will have a direct influence on the column efficiency. As the packing density increases, however, there is a commensurate and undesirable pressure drop increase across the packed portion of the column.
Many techniques have heretofore been developed for pack-ing chromatographic columnsu Thus, for example, U.S. Patent Nos. 2,~45,136 and 3,164,980 each describe packing techniques wherein the packing material is poured into the chromatographic column and compacted therein by vibration, tamping or the like. U.S. Patent Nos. 3,248,856; 3,522,172; 3,692,669 and 3,796,657 disclose packing techniques wherein the packing medium is fluidized by various techniques and then allowed to settle to form a packed bed. In "GAS CHROMATOGRAPHY 1960"
edited by R.P.W. Scott, published by sutterworths (London) at pages 240 et seg., the effect on packing structure of various modes of vibration, tapping, rotations, or combinations thereof is disclosed.
"A STUDY OF PACKED CAPILLARY COLUMNS," by V. G. Berezkin et al., Journal o Chromatography, 99 (1974) pages 111-112, discloses the packing o columns by simply tapping the packed column lightly by hand, or by moving a mechanical vibrator along the column. The authors also disclose the filling and packing of such columns utilizing a combination of an inert gas flow and low-frequency (50-100 Hz) electromechanical vibrators located at several positions along the column.
In "PERMEABILITY AND PREPARATION OF MICRO-PACKED COLUMNS,"
By J. A. Rijks et al., Chromatoyraphia, Volumn 8, No. 9, -September, 1975, pages 482 et seg., the authors disclose simultaneously filling and packing a micropacked column (i.e.
having a particle/column diameter rate between 0.1 and 0.3) with the use of ~radually increasing pressure and ultrasonic vibrations. The authors also disclose t~at a hand vibratox held on the surface of the container is employed to assist in provid~
ing a continuous stream of particles to the column.
Finally, in "POTENTIALITIES OF MICROPACKED COLUMNS SO~E AP-PL~CATIONS IN PETROLEUM CHEMISTRY," C. A. Cramers, J. Rijks and P. Bocek, ~. Chromatography, 65 (1972) 2937, a continuation of ultrasonic vibration and pressure is employed to simultaneously fill and pack a chromatographic column. This article also ::~
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notes that at the start of the procedure the pressurP increase shall be very gradual, and notes that care should be taken to maintain a substantially constant pressure product across the packing to ensure a homogeneous packing density.
Despite -the many techniques currently available, all of which employ various combinations of pressure and vibration, those skilled in the art still recognize the need for a packing technique which will maximize packing density while still im-posing a relatively low pressure drop across the packed portion of the column.
According to an embodiment of the present invention, there is provided a method of packing a chromatographic column, characterized by the steps of introducing a packing material into a chromatographic column under the influence of a first pressure differential and in the substantial absence of sub-stantially regular periodic vibration until said chromatographic column is filled to a desired extent with said packing material, and subsequently establishing a substantially regular periodic vibration along the length of said column and subjecting said packing material to a second pressure differential.
In a preferred embodiment of the present invention, the second pressure differential is greater than the first pressure differential, and preferably the substantially regular periodic vibrations along the length of the column comprise ultrasonic -~
vibrations, preferably produced by immersing the column in a bath of liquid and subjecting that liquid both to ultrasonic vi-brations. In another embodiment of the present invention, the first and second pressure differentials are maintained by intro-ducing a fluid such as an inert gas stream into the column, and preferably also by applying a vacuum ~o the end of the column.
In another embodiment of the present invention, any s~a-tic _ 5 _ ~11 5S5~L
charge on the packing material is reduced. For example, where an inert gas stream is utilized, the gas stream may be passed into contact with a radiation source prior to its entry into the column, or in another embodiment, the particles in the column are heated for that purpose.
In a preferred embodiment of the present invention where an inert gas stream is used to produce the first pressure differential, the column is purged of inert gas prior to esta-blishing the substantially regular periodic vibrations along the lengths of the column thereafter. Most preferably the column is subjected to the second pressure differential immediately after the establishment of the substantially regular periodic vibra-tion alony the length of the column, preferably comprising ultrasonic vibrations.
In yet another embodiment of the present invention, the second pressure differential is established substantially in-stantaneously, and in another embodiment irregular vibrations are applied to the column during the introduction of the packing material under the influence of the first pressure difEerential.
Those irregular vibrations can preferably be produced by tapping on the column itself.
In still another embodiment of the present invention, a plurality of steps are employed in connection with the intro-duction of the packing material into the column under the in-fluence of the first pressure dif~erential, with a portion of the packing material being introduced into the column in each of those steps. Preferably, irregular vibrations are applied to the column during each of those steps. Finally, the present invention comprises chromatographic columns packed in accordance with any of the foregoing methods.
In order that the invention may be fully understood, .. :
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embodiments of the invention will now be described with reference to the accompanying drawings, in which:
Flgure l is a schematic diagram illustrating an appa-ratus in which the method for packing a chromatographic column in accordance with an embodiment of the present invention can be effected; and Figure 2 is a schematic diagram illustrating an appa-ratus for effecting the method of an embodiment of the present invention used in conjunction with a monolithic glass chromato-graphic column.
The method of the present invention can be applied to a variety of chromatographic columns employing a variety of packing material therein. The columns can include glass and metallic columns, and can include columns generally referred to as micro-bore columns (i.e. generally having an inside diameter of be~
tween about .7 and 1.2 millimeters), and macrobore columns (i.e.
those having inside diameters greater than about 1.2 millimeters).
This technigue can also be applied to such columns wsed for both liquid and gas chromatographic purposes.
While a variety of packing materials can be utilized in connection with the methods hexeof, it must be borne in mind that certain types of packing materials will not be susceptible to the techniques of the present invention. That is, they cannot be packed more efficiently in accordance with the present inven-tion and achieve the improved results which are possible there-with. It is thus necessary that the packing material utilized have a sufficiently low friability or high crush strength during packing so as to avoid crushing or disintegration during packing under the conditions employed herein. If the materials utilized cannot maintain a substantial degree of their physical character-istics during packing, including the application of vibrations ~: :
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and pressures in accordance with this method, then the improved results achievable in accordance herewith cannot be realized with such packing materials.
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B~aring Ll~.is in mind, Lhe packi.ncJ m~lerials which ~arl ~e emL~loyed in co~ ection with the present invel~tion include a nu~ r of converltional chromatographic packing materials, generally conl~)risill(3 inert solids such as diatomaceous earth, alumina, glass beads, TeElon beads, graphitized carbon bl~lck, molecular sieves, silica yel (generally used in conjunction with high-pressure liquid chromatography) and the like. These inert packings of support materials are preferably of uniform par~lcle size and will generally range from about S to about 200 microns in particle size.
ReEerring to the figures, in which li.ke numerals refer -to like portions thereof, Figure 1 shows an apparatus for packing a conventional chromatographic column such as a convent.ional c~lass spiral colum~ 10 which is immersed in a water ba~h 12. The water bath can be made to cavitate by imparting ul-trasonic vibration~
thereto in a conventional manner. The effluent line 14 from the column leads to a vacuum pump (not shown), while the inlet line 16 to the column is connected to a reservoir 18 which con-tains the colu~ packing ma~erial. The reservoi.r 18, in turn, is connected to an iner~- gas feed line 20. Of course, where a liquid is to be utilized instead of the inert gas, such as ~or packing a ~olumn for use in high pressure liquid chromatography, analogous apparatus for applying such a liquid will be employed.
In instances wherein the packing material has been deactivated, e.g. ~herein the particles are treated with a silanizin~
reagerlt, the inert gas can be fed to the reservoi.r 18 through a line 22 whereby the inert gas is exposed to a radioactive sour(e 24 which expels ions in-to the gas stream for static elimil-ation pur~oses. The inert gas can be Eed directly i.nto the reservoir 18 via line 20 by closing valve 26 and opening valve 28. ~onversely, wherl i.t is desired to pass the i.nert gas * A trade mark through the radioactive source 24 and into the reservoir via line 22, valve 26 can be opened and valve 28 shut.
Before commencing the packing procedure of the present in-vention, it is generally necessary to first prepare the packing material therefor. Thus, for example, for most gas-liquid chromatography applications, it is generally considered preferable to pretreat the inert support materials to impart a silane coat-ing thereto. This ~s conventionally effected by reacting surface silanol groups with organic silane compositions, e.g. dimethyl-dichlorosilane. In any event, however, the particles are first pretreated to remove generally inorganic surface impurities from the support material by washing that material with acid.
Preferably the material is then treated to neutralize the acid and then dried.
In the case o~ gas chromatography, the inert support materials ;
can then be coated with a stationary liquid phase. Nearly any ~ `
unreactive non-volatile liquid can be used as the stationary phase. As a general rule, the boiling or decomposition point o~ ;
this liquid should be substantially above the column operating temperature in order to minimize its gradual vaporization. These stationary liquids can be divided into two groups: that is, those used in separations based upon non-selective columns, i.e.
where the separations are mainly due to differences in vapor pressures or diffusion rates of the components, (these liquids include silicon oils, greases and the like), and those used in separations based upon selective columns where there is a pre~er-red interaction of components with the stationary liquid phase based upon complementary chemical structures, ~these liquids include esters, alcohols, acids, amines and the like).
Typical stationary liquid phases include mineral oil, di- "
octyl phthalate, di-nonyl phthalate, silicone, methyl silicone, nitrobenzene, tricresyl phosphate/ dibutyl phthalate and the like. Particularly where the support material is porous in nature, it is preferable to degas the system after pouring the liquid over the support in order to assist the liquid in enter-ing the pores of this support material. Once the support or packing materials are coated with the stationary phase, they can then be filtered and dried, preferably with nitrogen, in order to remove any solvent therefromu The support can then be loaded into reservoir 18, and the packing procedure is ready to commence.
A chromatographically and chemically inert porous retainer is inserted into the terminal portion of the column proximate the junction of the column passageway with the outlet 14 in order to prevent loss of the packing material. Such retainers can be formed of fiber glass, glass wool, glass frits, an inert metal fiber, or wool such as gold wool and the like. Such retainers can eventually be interposed in the terminal portions of the inlet and outlet lines leading to and from the column to further protect against loss of packing material.
The chromatographic column 10 is attached to the inlet 16 from the reservoir 18 and the outlet 14 leading to the vacuum pump. It is then immersed in the water 30 contained within the ultrasonic bath 12. The packing apparatus is preferably kept in a room in which humidit~ can be controlled so that packing is effected under dry conditions.
The packing process includes an initial l'soft" packing of the inert support or packing material into the column under a mild pressure differential. Preferably, the column is first flushed with a stream of dry inert gas such as dry nitrogen, ~;
argon and the like. The packing operation is then initiated with the periodic addition of the packing material under the in-fluence of a first pressure differential through the column~
This pressure differential can be established ei-ther by using ~O
an inert gas pressure as discussed above, or preferably by means o~ a vacuum applied to the column, or most preferably by utilizing both such an inert gas pressure and a vacuum. This is conducted in a manner so as not to result in a segregation of the particles in terms of various particle sizes therein.
Preferablyr while maintaining the first pressure differential across the column, separate portions of the packing materials are added to the column, and irregular vibrations can be ap-plied to the column, such as by periodically tapping or rapping ;
reservoir 18, or, as another alternative, cavitating the ultra-sonic bath for short periods, for example, up to about 2 seconds at a time, to achieve similar effects. Such a procedure is carried out in order to remove any blockage which may be present in the column. At the same time, the presence of substantially regular periodic vibration along the length of the column is avoided during this stage of the packing process, such as the avoidance of cavitating the ultrasonic bath for significant periods of time throughout this phase of the packing operation.
In other words, what must be avoided is the establishment of a regular wave form within the column, e.g. sinusoidal, triangular, square, etc., so that random loading of the column is insured to prevent the segregation of particle sizes.
As for the actual pressure differential which is established during this soft packing phase of the method of the present in vention, this will depend somewhat on the type o column and the type of packing being applied therein. Thus, the linear gas velocity achieved by any given flow of fluid or gas through the column will be dependent upon the size of the column bore and the average particle size of the packing matexial. As a specific -~
example (for gas chromatography), with a microbore column having a diameter of between about .7 and 1.2 millimeters, and utilizing particles having an average particle size of between about 5 and 75 microns, preferably between about 37 and 44 microns, a first pressure differential hiyh enough to initiate movement of the particles from the reservoir into the column, such as between about 5 and 50 pounds per s~uare inch differential (psid.) per yard of column length will generally be employed.
On the o~her hand, with a macrobore column having a diameter of above about 1.2 millimeters and utilizing a packing material having an average particle size of between about 50 and 200 microns, preferabl~ between about 74 and 84 microns, a first pressure differential between about 5 and 25 psid per yard of column length will be utilized.
Once the column is filled with the packing material to the extent desired, the pressure differential employed in filling the column is substantially abated. For example r where the fluid is a gas, the vacuum is continued at the column outlet for a short period, e.g. 15 minutes. At this point, ca~itation of the ultrasonic bath can be commenced. The bath will generally cavitage when e~posed to an ultrasonic frequency above about 15 kilohertz. Once ultrasonic vibration is commenced along the length of the column the packing material can then be subjected to a second pressure differential, greater than the first pres-sure differential, and agaln dependent upon the size of the column bore and the average particle si~e of the packing material.
Once again, increased particle size packing material will generally permit the use of lower pressure di~ferentials. Utilizing a flow of inert gas to establish the second pressure di~ferential, the differential is substantially ins-tantaneously produced in the column so as to jolt the packing material previously soft packed in the now vibrating column.
While the use of ultrasonic vibration has been discussed above, the significant factor is that in this second phase a \~ :
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substantially regular periodic vibration is established along the length of the column. While the use of fairly short wave length vibrations such as those comprising a low multiple of the average particle diameter of the packing materials are preferred, it is possible to employ longer wave lengths. It is therefore possible to use sonic vibration therein preferably with higher energies therewith. The significant fact is that there is a substantially constant vibration produced in the bed and the packing particles act like a fluidized bed therein. Preferable frequencies of between about 30 and 60 kilohertz are employed.
This procedure results in a maximization of packing density within the column and the concomitant significant improvements realizable in accordance with the present invention.
This second phase can preferably be continued or a period of between about 5 minutes up to about 10 hours, alth~ugh generally periods of between about 5 minutes and 30 minutes are suf-Eicient.
Again considering the previous discussion with respect to the relationship between the pressure differential utilized and the inside diameter of the col~lmn, as well as the average particle size of the packing material utilized, in a microbore column utilizing packing materials having average particle sizes as described above, generally a pressure differential of between about 50 and 500 psid per yard of column length will be utilized.
On the other hand, with a macrobore column utilizing packing materials having average particle sizes as described above, a pressure differential of between about 25 and 250 psid per yard of column length will be utilized. Generally, the second pressure differential must be sufficient to settle the bed and obtain maximum packing density, but cannot be too great so that the gas velocity within the column is elevated to a point where the particles being utilized tend to immobilize or jam and can-not be sufficiently packed therein.
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After the application of this second pressure differen-tial and substantially regular vibration along the column, the ultrasonic bath is turned off and the fluid pressure is terminated.
Any residual pressure is allowed to reduce to ambient pressure slowly so as to avoid disturbing the packing in the column, and any residual fluid in the system is allowed to slowly bleed off. Thereafter, the pa~ked chromatographic column can be disconnected from lines 14 and 16 and a porous retainer as described hereinabove can be inserted into the initial portion of the continuous passageway of the column proximate the junc-tion of the passageway with the inlet 16 thereby sealing the packing within the passageway of the column.
It has been found that columns packed in the foregoing manner exhibit significantly higher separation efficiencies than have heretofore been obtainable by other known prior art techniques. Moreover, even though the packing density is maximized in accordance with the method of the present lnven-tion, it has been found that the pressure drop across the column is still relatively low. ~he packing technique of the present invention enables the obtaining of significantly greater column efficiencies, for example, with a typical gas chromatography -~
microbore column, column eficiencies of up to about 1,000 plates per foot were previously achievable, but in accordance with the present invention it is possikle to achieve column efficiencies of between about 2~000 and 3,000 plates per foot. On the other hand, with a typical gas chromatography macrobore column it was previously possible to obtain consistent column éfficiencies of between about 200 and 800 plates per foot, while in accordance with the present invention effisiencies of between about 1,000 and 1,500 plates per foot can now be achieved. Again~ however, each o these specific efficiencies relate to the particular ~S~5~
column under consideration, and will vary with the diameter of the column bore, the particles being employed, etc.
~ eferring to Figure 2, another embodiment o~ the present invention is shown wherein a monolithic glass chromatographic column 32 is shown being packed in accordance with the method of the present invention. The monolithic glass chromatographic column has a continuous passageway formed therethrough which can be packed with chromatographic packing material in accordance with the present invention. Quick-connect and disconnect couplings 34 and 36 enable the column to be connected and disconnected from the packing system of the present invention. Moreover, these couplings enable the packed chromatographic column to be readily connected to gas feed and analytical devices.
If it is desired to further eliminate the static charge car-ried by the packing particles, the use of the radiation source 24 can be employed, or alternatively or in combination therewith, the inside diameter of the passayeway through the chromatographic column can be coated with a non-reactive and non-catalytic metal such as gold. This can be done by conventional vacuum metallizing techniques.
With reference to Figure 1, an apparatus as shown therein was utilized wherein the effluent line 14 was connected to a ballast chamber of approximately 6 gallons capacity. The bal-last chamber was then connected to a Precision Scientific Corpora-tion model D-75 vacuum pumpj and a ~hitey ball valve was in-cluded in effluent line 14 in order to permit rapid opening of ;~
the effluent line to the ballast chamber. The ballast chamber was used in order to provide a greater reservoir of vacuum ~or ~ -the system.
The column employed was a 6 foot long glass coil 1/4 inch O.D. by 2 millimeters I.D. configured to fit a Hewlett-Packard `:
5700 yas chrorlldto~Jraph, column confiyuration 5. 'l'l~e re~ervoir 18 corlsisted of a l foot lencJth of 3/8 inch O.U. t)y .280 inch I . D. stainless tube connected to the inlet line 16 by means of a SWAG~:I.OC~ 3/8 inch -to l/4 inch brass reducinc~ couplin-J which had been drilled through to l/4 inch I.D. to pe~nit insertion of the column into the reservoir above the level of the fitting.
The top of the reservoir was fitted with a SWAGELOCK 3/8 inch sin~le-end shut-off quick connect coupling which then connected to a Whitey ball valve 28. In this example, the inert gas was ~ed directly into the reservoir 18 through line 20.
The upstream or high pressure end oE -the Whitey ball valve 28 was connected by rneanS of a SWAGELOCK l/4 inch sin~3le~
end shut-of~ ~luick connect to a supply of nitrogen with a reyu-lator which could control between 0 and 200 psig. 'rhe ultrasonic bath 12. was a BRANSONICS model B-52 bath and the fluid in the bath was water with a small amount of bis(2-ethylhexyl) sulfo-succinate, sodium salt in order to reduce the surEace tension and permit better -transduction of the ultrasonic vibration. The support employed was prepared from 30 to 60 mesh CHROMOSORB G
which was ground and screened to produce a support having a n~rrow ranye particle size of between about 100 and 110 microns, employiny electroformed round holed screens as supplied by Stork America Corporation. The ground support was then washed exhaus-tive]y with 8 N hydrochloric acid until the supernatant had no detectable yellow coloration.
After acid washiny, the support was rinsed with de-ioni~ed water until the supernatant was neutral and there was no detectable clc~udiny of the supernatant due to fines. rrhe support was dried overniyht in a 110~C oven, allowed -to cool, and -the coated wi-th licluid phase. Coatiny was accomL~lished by trans-ferring a weicJhed (~uantity o~ support to a round bot-tom c~round * A trade mark - 16 -joint flask and coverinc~ with a solution of 5'~ CARI~OW~X 20M
in ethylene - 16a -* A trade mark .~. .
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dichloride (wei(~ er volume), in the E~ro~ortion c,t 2milliliter~ of coatirl~ solution to each (Jrarn of su~l-oLt.
'rhe resu1tincJ slurry was tllc~ll degassed by subjectirlg it ~o a vacuum while vibLatinc~ in arl ultrasonic ~ l in ord~r to insure complete penetration of the coatiny solution ;nto the ~ores of the su~~ort. The slurry was transferred to a coarse frit Buchner ~unnel with an additional arnount of coating solu-tion (also in the proportion oE 2 milliliter per gram of sup~
port) used ~s a rinse to effect complete transfer. The slurry w~s then filtered under vacuum un-til the solution ceased to drop freely from the end of the funnel. The damE~ support was then transferred to a fluidized bed drier (~ EE'F' fluidizer manufactured by Applied Science Laboratories) ancd dried by fluidizing with a s-tream of warm nitrogen. Five grams oE the resul-ting packing material was introduced to the reservoir 18, the systesn was reconnected and filling was commenced.
With the valve 28 closed and with the valve between the effluent line 14 and the ballast tan~ also closed, the ballast tank was evacuated. The valve in the effluent line was then opened and the reservoir 18 tapped periodically to assist the flow of the packing material into the column. When the filling process slowed, with 0 psig. on the nitrogen regulator, valve 28 was opened to continue the filling process. Whe~ the filling process again slowed, valve 28 was closed, ~0 psig.
was applied from the nitroc3en regulator, and valv~ 28 was again opened to complete the filling process. With the column full and no visible voids therein, a timer was therl set for 15 minutes durln~ which time the vacuum pum~ was allowed to con-tinue to evacua-te ~as from the column. At the end of this time perio~, the nitrocJen pressure was raised to 80 l~ounds, t~-le ultrc,sonic bath was switclled on~ arld valve ~8 wa~ opened to * A trade mark - 17 -.~ .
begin packing of the column. A timer was set for 10 minutesand packing allowed to continue for this period. The ultra-sonic bath was switched off and valve 28 was then closed and the residual pressure allowed to bleed from the effluent line.
While specific embodiments of the chromatographic column packing method of the present invention have been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore, it is intended that no limitations be placed on the invention except as defined by the scope of the appended claims.
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Claims (25)
1. A method of packing a chromatographic column, comprising the steps of introducing a packing material into the said chromatographic column under the influence of a first pressure differential and in the substantial absence of substantially regular periodic vibration until said chromatographic column is filled to a desired extent with said packing material, and subsequently establishing a substantially regular periodic vibration along the length of said column and subjecting said packing material to a second pressure differential.
2. A method according to Claim 1, wherein said second pressure differential is greater than said first pressure differential.
3. A method according to Claim 2, wherein said subse-quently established subsantially regular periodic vibration comprises ultrasonic vibration.
4. A method according to Claim 3 J wherein said ultra-sonic vibration is produced by immersing said column in a liquid-containing bath and subjecting said liquid in said bath to ultrasonic vibration of a frequency greater than about 15 kilocycles per second.
5. A method according to Claim 1, 2, or 3, wherein said first and second pressure differentials are produced at least in part by introducing a fluid stream into said column.
6. A method according to Claim 1, 2, or 3, further comprising the step of substantially abating said first pressure differential prior to establishing said substan-tially regular periodic vibration along the length of said column.
7. A method according to Claim 1, 2, or 3, wherein said column is subjected to said second pressure differential immediately subsequent to the establishment of said substan-tially regular periodic vibration along the length of said column.
8. A method according to Claim 1, 2, or 3, wherein said second pressure differential is established substantially instantaneously.
9. A method according to Claim 1, 2, or 3, further comprising the step of applying an irregular vibration to said column during the introduction of said packing material under the influence of said first pressure differential.
10. A method according to Claim 1, 2, or 3, further comprising the step of applying an irregular vibration to said column during the introduction of said packing material under the influence of said first pressure differential by tapping intermittently on said column.
11. A method according to Claim 1, 2, or 3, further comprising the step of reducing the residual pressure in said column after the termination of said second pressure differential therein.
12. A method according to Claim 1, 2, or 3, wherein said first and second pressure differentials are produced at least in part by applying a vacuum to one end of said column.
13. A method according to Claim 1, 2, or 3, wherein said column has an inner diameter of between about .7 and 1.2 millimeters, said first pressure differential ranges between about 5 and 50 psid per yard of column length, and said second pressure differential ranges between about 50 and 500 psid per yard of column length.
14. A method according to Claim 1, 2, or 3, wherein said column has an inner diameter of greater than about 1.2 millimeters, said first pressure differential ranges between about 5 and 25 psid per yard of column length, and said second pressure differential ranges between about 25 to 250 psid per yard of column length.
15. A method according to Claim 1, 2, or 3, wherein said packing material has an average particle size of between about 5 and 200 microns.
16. A method according to Claim 1, 2, or 3, wherein said packing material has an average particle size of between about 5 and 75 microns.
17. A method according to Claim 1, 2, or 3, wherein said packing material is selected from a group consisting of diatomaceous earth, alumina, glass beads, Teflon beads, graphitized carbon black, molecular sieves, silica gel, and mixtures thereof.
18. A method according to Claim 1, 2, or 3, wherein said packing material has an average particle size of between about 50 and 200 microns and said chromatographic column has an inner diameter of greater than about 1.2 millimeters.
19. A method according to Claim 1, wherein the intro-duction of said packing material into said column under the influence of said first pressure differential comprises a plurality of steps, with a portion of said packing material being introduced into said column in each of said steps.
20. A method according to Claim 19, further comprising applying an irregular vibration to said column during each of said plurality of steps.
21. A method according to Claim 1, 2, or 3, wherein said substantially regular periodic vibration is maintained for a period of from about 5 minutes to 10 hours while subjecting said packing material to said second pressure differential.
22. A method according to Claim 1, 2, or 3, wherein said substantially regular periodic vibration is maintained for a period of from about 5 to 30 minutes while subjecting said packing material to said second pressure differential.
23. A method according to Claim 1, 2, or 3, further comprising the step of coating the passageway through the chromatographic column with a non-reactive metal.
24. A chromatographic column packed with a packing material which has been packed into the chromatogaphic column by introducing it into the said chromatographic column under the influence of a first pressure differential and in the substantial absence of substantially regular periodic vibration until said chromatographic column is filled to a desired extent with said packing material, and subsequently establishing a substantially regular periodic vibration along the length of said column and subjecting said packing material to a second pressure differential.
25. A method of packing a chromatographic column which comprises introducing a packing material into a chromatographic column in a predetermined direction under the influence of a first pressure differential and in the substantial absence of substantially regular periodic vibration until said chromato-graphic column is filled to a desired extent with said packing material, and subsequently establishing a substantially regular periodic vibration along the length of said column and sub-jecting said packing material to a second pressure differential therein, said first and second pressure differentials being applied in said predetermined direction so as to aid in filling and packing said column with said packing material.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US894,716 | 1978-04-10 | ||
| US05/894,716 US4175037A (en) | 1978-04-10 | 1978-04-10 | Process for packing chromatographic columns |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1115551A true CA1115551A (en) | 1982-01-05 |
Family
ID=25403444
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA308,074A Expired CA1115551A (en) | 1978-04-10 | 1978-07-25 | Process for packing chromatographic columns |
Country Status (10)
| Country | Link |
|---|---|
| US (1) | US4175037A (en) |
| JP (1) | JPS54134695A (en) |
| AU (1) | AU528110B2 (en) |
| CA (1) | CA1115551A (en) |
| CH (1) | CH637843A5 (en) |
| DE (1) | DE2838086A1 (en) |
| FR (1) | FR2422426A1 (en) |
| GB (1) | GB1597338A (en) |
| NL (1) | NL7808498A (en) |
| SE (1) | SE7809128L (en) |
Families Citing this family (30)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3042907C1 (en) * | 1980-11-14 | 1982-05-27 | Bodenseewerk Perkin-Elmer & Co GmbH, 7770 Überlingen | Method and device for measuring atomic absorption and emission while producing a gaseous measurement sample |
| GB2128099B (en) * | 1982-10-04 | 1986-07-02 | Varian Associates | Narrow bore microparticle column packing process and product |
| FR2533836B1 (en) * | 1982-10-05 | 1988-01-22 | Elf Aquitaine | METHOD AND DEVICE FOR FILLING CHROMATOGRAPHIC COLUMNS |
| FR2616546B1 (en) * | 1987-06-15 | 1989-09-08 | Commissariat Energie Atomique | APPARATUS FOR FILLING COLUMNS OF LIQUID CHROMATOGRAPHY BY PYROTECHNIA |
| JPH01245153A (en) * | 1988-03-26 | 1989-09-29 | Daicel Chem Ind Ltd | Treatment of polymer deposited type packing material |
| US4985143A (en) * | 1988-06-06 | 1991-01-15 | The University Of Maryland | Method for packing chromatographic beds |
| US5067528A (en) * | 1989-07-19 | 1991-11-26 | Digital Equipment Corporation | Hydrodynamic bearing |
| US5766460A (en) * | 1992-11-02 | 1998-06-16 | Pharmacia Biotech Ab | Liquid chromatographic system |
| AU1474899A (en) * | 1997-12-10 | 1999-06-28 | Prior Separation Technology Gmbh | Method for charging the particle bed space of a chromatograph |
| AT405248B (en) * | 1997-12-10 | 1999-06-25 | Prior Eng Ag | Feed process |
| CN1386196A (en) * | 2000-07-28 | 2002-12-18 | 欧洲流程(英国)有限公司 | Method and apparatus for packing chromatography columns and chromatography column |
| US6402958B1 (en) * | 2000-08-17 | 2002-06-11 | Uop Llc | Chromatography column loading method |
| JP3965443B2 (en) * | 2001-04-17 | 2007-08-29 | エルジー・ケム・リミテッド | Spherical carbon and its manufacturing method (SPHERICA LCARBONSANDMETHOD FORPREPARINGTHEMEME) |
| US20020176800A1 (en) * | 2001-05-09 | 2002-11-28 | Henry Richard A. | Curved miniature liquid chromatography column |
| US6787029B2 (en) * | 2001-08-31 | 2004-09-07 | Cabot Corporation | Material for chromatography |
| US7261812B1 (en) | 2002-02-13 | 2007-08-28 | Nanostream, Inc. | Multi-column separation devices and methods |
| EP1348957A1 (en) * | 2002-03-27 | 2003-10-01 | Büchi Labortechnik AG | Device and process for filling a column with a filling material |
| US7351332B2 (en) * | 2003-10-17 | 2008-04-01 | Varian, Inc. | Chromatography cartridge and method for manufacturing a chromatography cartridge |
| US20060054872A1 (en) * | 2004-03-01 | 2006-03-16 | Pebble Bed Modular Reactor (Propriety) Limited | Nuclear fuel |
| US8071959B2 (en) * | 2005-12-21 | 2011-12-06 | Ottawa Heart Institute Research Corp. | Rubidium generator for cardiac perfusion imaging and method of making and maintaining same |
| US20070181501A1 (en) * | 2006-02-08 | 2007-08-09 | Agilent Technologies, Inc. | Method and apparatus for packing chromatography column |
| US9116150B2 (en) | 2007-11-19 | 2015-08-25 | Emd Millipore Corporation | Method of and device for packing a chromatography column |
| US9151734B2 (en) * | 2009-03-05 | 2015-10-06 | Idex Health & Science Llc | Connection assembly for ultra high pressure liquid chromatography |
| CA2785198C (en) * | 2009-12-22 | 2018-02-27 | Ge Healthcare Bio-Sciences Ab | Method for dry packing of chromatography columns |
| EP2561345A4 (en) | 2010-04-05 | 2015-02-25 | Purdue Research Foundation | Method of packing chromatographic columns |
| DE112012003041T5 (en) * | 2011-07-19 | 2014-04-17 | Velocys, Inc. | Microchannel reactors and manufacturing processes |
| WO2013134087A1 (en) * | 2012-03-05 | 2013-09-12 | Waters Technologies Corporation | Corrosion protection in tubing used in chromatography |
| CN105738540A (en) * | 2016-01-27 | 2016-07-06 | 河南大学 | Negative pressure type quartz capillary monolithic column manufacturing device and use method thereof |
| WO2018185536A1 (en) * | 2017-04-07 | 2018-10-11 | Mechem Lab Ltd. | Elbow type gas purifier and method of its production |
| CN109406696A (en) * | 2018-12-25 | 2019-03-01 | 上海神开石油科技有限公司 | Chromatographic particle fills percussion device |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2845136A (en) * | 1955-09-12 | 1958-07-29 | Cons Electrodynamics Corp | Chromatography |
| US3164980A (en) * | 1960-06-23 | 1965-01-12 | Phillips Petroleum Co | Gas-liquid partition chromatography |
| FR1337269A (en) * | 1962-06-07 | 1963-09-13 | Pechiney Saint Gobain | Process for filling columns for separation by gas chromatography |
| GB1036596A (en) * | 1962-10-08 | 1966-07-20 | William Antony Wiseman | Improvements in apparatus for gas chromatography |
| GB1088421A (en) * | 1964-01-07 | 1967-10-25 | Harshaw Chemicals Ltd | A method and apparatus for depositing a coating on the internal walls of capillary or smallbore tubes |
| DE1498788A1 (en) * | 1964-03-19 | 1969-11-13 | Halasz Dr Istvan | Small diameter packed separation columns for liquid chromatography |
| US3796657A (en) * | 1965-05-11 | 1974-03-12 | V Pretorius | Apparatus for distribution separation processes,their manufacture and use |
| GB1183833A (en) * | 1966-08-11 | 1970-03-11 | Victor Pretorious | Improvements in Chromatographic Processes and Apparatus. |
| US3429743A (en) * | 1966-11-17 | 1969-02-25 | Branson Instr | Shock wave treatment method and apparatus |
| US3692669A (en) * | 1970-08-10 | 1972-09-19 | California Inst Of Techn | Method and apparatus for micro dry column chromatography |
| DE2128090A1 (en) * | 1971-06-05 | 1972-12-14 | Siemens Ag | Chromatography column prodn - by progressive depositon of bed material from withdrawing tube |
| GB1457273A (en) * | 1973-05-23 | 1976-12-01 | Wellcome Found | Column packing device |
-
1978
- 1978-04-10 US US05/894,716 patent/US4175037A/en not_active Expired - Lifetime
- 1978-05-31 GB GB25930/78A patent/GB1597338A/en not_active Expired
- 1978-07-25 CA CA308,074A patent/CA1115551A/en not_active Expired
- 1978-08-03 AU AU38595/78A patent/AU528110B2/en not_active Expired
- 1978-08-16 NL NL7808498A patent/NL7808498A/en not_active Application Discontinuation
- 1978-08-23 FR FR7824500A patent/FR2422426A1/en not_active Withdrawn
- 1978-08-29 JP JP10545078A patent/JPS54134695A/en active Pending
- 1978-08-30 SE SE7809128A patent/SE7809128L/en not_active Application Discontinuation
- 1978-08-31 DE DE19782838086 patent/DE2838086A1/en not_active Withdrawn
- 1978-11-06 CH CH918178A patent/CH637843A5/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| SE7809128L (en) | 1979-10-11 |
| JPS54134695A (en) | 1979-10-19 |
| AU528110B2 (en) | 1983-04-14 |
| US4175037A (en) | 1979-11-20 |
| NL7808498A (en) | 1979-10-12 |
| DE2838086A1 (en) | 1979-10-18 |
| FR2422426A1 (en) | 1979-11-09 |
| AU3859578A (en) | 1980-02-07 |
| CH637843A5 (en) | 1983-08-31 |
| GB1597338A (en) | 1981-09-03 |
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| MKEX | Expiry |