WO2012006826A1

WO2012006826A1 - Combined detection device for underwater raman-fluorescence spectrum

Info

Publication number: WO2012006826A1
Application number: PCT/CN2010/077805
Authority: WO
Inventors: 郭金家; 刘智深
Original assignee: 中国海洋大学
Priority date: 2010-07-16
Filing date: 2010-10-16
Publication date: 2012-01-19
Also published as: CN101915755A; CN101915755B

Abstract

A combined detection device for underwater Raman-fluorescence spectrum includes a housing (1) used as a sealed cabin, an optical window (3) and a cable joint (9) provided on the housing (1), a spectrograph in the housing (1) consisting of a laser (2), a pre-positive optical path (4), an optical fiber (5), a grating (6) and a detector (7), and an electronic control module (8). The grating (6) is a composite grating, which includes an upper grating (10) with high resolution and a lower grating (11) with low resolution. An angle between the upper grating (10) and the lower grating (11) is θ. The laser (2) is used as the exciting source for Raman spectrum and fluorescence spectrum simultaneously, and the Raman spectrum and fluorescence spectrum of underwater substance can be acquired simultaneously.

Description

Water Pullman - Fluorescence Spectroscopy Detection 3⁄4g

Technical field

The invention belongs to a marine chemical spectrum detecting device, and particularly relates to a water pullman-fluorescence spectrum combined detecting device.

Background technique

At present, most marine chemical detection needs to collect samples and send them back to the water for analysis.

The chemical transmission of on-site detection under 7j, the existing on-site detection chemical transmission is mostly for the real-time and in-situ analysis of specific components, and the lack of multi-parameter simultaneous analysis of on-site detection chemical transmission.

In recent years, some multi-parameter ocean chemistry detection techniques using laser spectroscopy, such as Raman spectroscopy and fluorescence spectroscopy, have been developed, but they are all applications of single spectral detection technology. For the usual underwater in-situ detection, for example, in the case of near-shore seawater, due to the presence of a large amount of fluorescent substances, Raman is excited by ultraviolet and visible light bands, and the interference of fluorescence is very serious, and even the Raman signal is completely concealed, and the near-infrared wavelength is adopted. Excitation, the tree can inhibit fluorescence, but the excitation efficiency is low. Fluorescence spectroscopy can only detect some major organic components such as colored organic matter in seawater. For some low-content but highly harmful substances, such as polycyclic aromatic hydrocarbons, the fluorescence signal is completely annihilated in the fluorescent spectrum of colored Mm. in.

In view of the complexity and diversity of the composition of seawater, the detection of the chemical composition of marine materials requires a comprehensive range of information, and due to the limitations of marine operating conditions, it is hoped that the measuring instrument will be deployed once more to obtain as many turns as possible. Instrumentation with integrated measurement or detection capability is required for ifcm cutting.

Summary of the invention

The object of the present invention is to provide a water pullman-fluorescence spectrum! ^Detection device can simultaneously realize the Raman spectrum and fluorescence spectrum detection of seawater components to compensate for the shortcomings of the prior art in real-time detection of marine chemistry.

The invention combines Raman spectroscopy fluorescence spectroscopy techniques. Raman spectroscopy is excited by deep ultraviolet wavelength (220~270nm). Since the Raman spectral signal is inversely proportional to the fourth power of the excitation wavelength, the signal intensity will be several times or even higher than that of the normal visible and near-infrared wavelength excitation. Hundreds of times of improvement, that is, «high efficiency, and because the fluorescence of the material in seawater is often greater than 300nm, it is excited by a deep ultraviolet wavelength laser source, the Raman spectrum is less than 300nm, and there is no β with the fluorescence inch spectrum, and the ideal pull can be obtained. Mann spectrum. In addition, since the photon energy of the ultraviolet light is equivalent to the energy difference between the electrons, the deep ultraviolet wavelength excitation is easy to obtain the resonance Raman spectrum, which can enhance the signal. For fluorescence spectroscopy, many organic substances dissolved in seawater have an absorption wavelength concentrated at 220-270 nm, and a higher fiber efficiency with deep ultraviolet wavelength.

As mentioned above, excitation with deep ultraviolet wavelengths has higher excitation efficiency for both Raman and fluorescence spectroscopy, and the excitation wavelength range of these two spectra has consistency, ranging from 220 to 270 nm. The Raman spectrum and the fluorescence spectrum of the excitation are different in the spectral range, that is, the Raman spectrum is <300 nm, the fluorescence spectrum is >300 nm, and the separation is easy. 3⁄4!3⁄4 is the basis of the present invention. The technical solution of the present invention comprises an outer casing as a sealed compartment, an optical window and a cable joint on the outer casing, and a spectrometer composed of a laser, a front optical path, an optical fiber, a grating, a detector, and an electronic control module, and characterized in that The grating is a combined grating: a high-grating upper grating, a low-contention lower grating, and an S±3⁄4 upper grating and a lower grating have a certain angle θ.

The upper grating has a power rate of 3600 grooves / mm and a size of 32 X 16 mm.

The lower grating is 300 grooves/mm and the size is 32 X 16mm.

The laser is also used as a laser source for Raman spectroscopy and fluorescence spectroscopy, and its wavelength is 220-270 nm. The photodetector is an ultraviolet enhanced area array CCD or EMCCD.

A key part of the technique of the present invention is a combined grating as a spectroscopic device in a spectrometer, which simultaneously performs separation and detection of Raman and fluorescence spectra. The combined grating consists of two upper and lower gratings with different angles and a certain angle. The Raman and fluorescence hybrid spectra generated by the laser irradiation target are irradiated to the combined grating. Since the upper and lower gratings have different content rates and different incident angles, Therefore, the Raman spectrum and the fluorescence spectrum can be separated from each other in space, and the Raman spectrum and the fluorescence spectrum are respectively obtained, and then the spectral shipfront array photoelectric detection requirements are separated, and the spectral signal is converted into an electrical signal input calculation «t line processing . Since the Raman and fluorescence spectra have the same excitation wavelength, the same laser can be used as the fiber source, which is small in volume and high in excitation efficiency.

DRAWINGS

Figure 1 is a schematic view of the overall structure of the present invention.

2 is a schematic perspective view showing the combined grating of the spectroscopic device of the spectrometer of the present invention.

Among them, 1. outer casing, 2. laser, 3. optical window, 4. front optical path, 5. optical fiber, 6. grating, 7. detector,

8. Electronic control module, 9. Cable connector, 10. Upper grating, 11. Lower grating.

Specific 3⁄4»

As shown in Fig. 1, the invention comprises a casing 1 of a sealed compartment, an optical window 3 and a cable joint 9 on the casing 1, and a laser 2, a front optical path 4, an optical fiber 5, a grating 6, and a detector 7 in the casing 1. The spectrometer, and the corresponding electronic control module 8, characterized in that the grating ό is a combined grating: a high-content upper grating 10, a low-resolution lower grating 11, and an angle between the upper and lower gratings 10, 11. For θ, Θ is determined by the formula 0=|((3⁄4-(3⁄4 (β!-β ₂ )|/2).

Wherein, ^ is the incident angle and the exit angle of the upper grating (10), respectively, and β ₂ is the incident angle and the exit angle of the lower grating (11), respectively.

Usually the angle of the grating is determined by the grating equation, which is obtained according to the existing grating equation:

(m I ά)λ = α -\- sin β

In the above formula, it is the diffraction order, which is the distance between the grating marks, that is, the reciprocal of the number of marks per mm (line pair) of the grating, λ is the center wavelength of the diffracted light, and α and β are the incident angles of the grating, respectively. Exit angle. For the upper grating 10, the incident angle and the exit angle are set to (3⁄4 and for the lower grating 11 the incident angle and the exit angle are α ₂ and β ₂ , then the above angle 0 = |( -(3⁄4 1-32)|/ 2. For example, using a 248 nm laser as the excitation light source, the angle Θ between the upper grating 10 and the lower grating 11 is 26.04°.

The upper grating 10 described above is 3600 grooves/mm (line pair/mm), and the size is 32X 16 mm. The angle of the grating is changed by the laser wavelength selected by the kit, and the angle of the grating is determined by the grating equation. For example, a 248 nm laser is used as the excitation source, and the grating incident angle is 6.75°.

The ±3⁄4 lower grating 11 is 300 grooves/mm, the size is 32X 16mm, the center wavelength is 565nm, and the grating angle is fixed at an incident angle of 19.31°.

The laser 2 is simultaneously used as a laser source for Raman spectroscopy and fluorescence spectroscopy, and is difficult to be 220 to 270 nm. Detector 7 is UV-enhanced area CCD or EMCCD. In order to obtain the ship's contention rate, the pixel of the area array is 2048 X 2048. For example, PKIS: 2048BUV CCD of Princeton Instruments can be used, and its Raman and fluorescence spectra are used. The Raman spectrum and the fluorescence spectrum signal can be obtained by respectively reading the values of different detectors at different positions of the area array detector.

The invention uses a 248 nm laser, a 150 mm focal length spectrometer and a 2048 X 2048 pixel CCD as an example. The upper grating corresponds to a spectral range of 29 nm (248.5 to 277.5 nm) and a spectral resolution of 0.035 nm. The lower grating corresponds to a spectral range of 531 nm (299.5~830.5 nm) with a spectral resolution of 0.65 nm. The requirements for spectral detection range and spectral rate of Raman and fluorescence spectra can be met simultaneously.

In the specific implementation of the present invention, taking the excitation light source to select a 248 nm laser as an example, a part of the polycyclic aromatic hydrocarbons will resonate at this wavelength, greatly enhancing the detection spirit, thereby realizing the detection of polycyclic aromatic hydrocarbons by resonance Raman spectroscopy, and adopting deep ultraviolet rays. Excitation, not only can obtain the usual seawater colored ffi signal, but also can obtain the fluorescence signal of organic matter of proteins such as tryptophan. This uses the deep-UV wavelength as the excitation source for underwater Raman-fluorescence spectroscopy! ^The detection device enhances the detection of low-level components on the one hand, and broadens the scope of the object « to obtain more comprehensive information.

l k practicality

Obviously, the invention can simultaneously obtain the Raman spectrum and the fluorescence spectrum of the substance in water, that is, realize the water drop spectrum and the fluorescence spectrum! ^Probing, wide adaptability, can be applied to offshore environmental pollution monitoring and deep sea oil and gas resource exploration, etc., to provide a more comprehensive information detection means for marine chemical detection.

Claims

Claim

1. A water pull-mantle-fluorescence spectroscopy combined detection device comprising a sealed capsule housing (1 housing (1) on the optical window (3) and cable connector (9), and housing (1) inside the laser (2 front) a spectrometer comprising a light path (4), an optical fiber (5), a grating (6), a detector (7), and an electronic control module (8), characterized in that the grating (6) is a combined grating: high resolution Upper grating (10), low resolution lower grating (11), and the angle between the upper and lower gratings (10, 11) is θ, by the formula

determine,

Where ^ and are respectively the incident angle and the exit angle of the upper grating (10), α ₂ and β ₂ are the incident angle and the exit angle of the lower grating (11), respectively; the incident angle and the exit angle of the grating are generally according to the existing grating equation determine:

Where is the diffraction order, 6 is the distance between the grating marks, that is, the reciprocal of the number of marks per mm of the grating, λ is the center wavelength of the diffracted light, and α and β are the incident and exit angles of the grating, respectively.

2. The water pullman-fluorescence spectroscopy combined detecting apparatus according to claim 1, wherein said laser (2) simultaneously serves as a laser light source for Raman spectroscopy and fluorescence spectroscopy, and has a wavelength of 220 to 270.

A water-drawing-fluorescence spectroscopy combined detecting apparatus according to claim 1, wherein said upper grating (10) is 3600 grooves/mm.

A water-drawing-fluorescence spectroscopy combined detecting apparatus according to claim 1, wherein said lower grating (11) is 300 grooves/mm and a center wavelength is 565 nm.

The water drop-fluorescence spectroscopy combined detecting apparatus according to claim 1, wherein said detector (7) is an area array CCD or EMCCD.