An integrated microfluidic chip organic solvent raman spectrum detection system

Abstract

The application provides an integrated microfluidic chip organic solvent Raman spectrum detection system and relates to the technical field of spectrum, which comprises a Raman spectrum excitation detection light path, a microfluidic chip, a positioning table, a peristaltic pump, a power supply, an instrument shell and spectrum analysis software; under the driving of the peristaltic pump, the organic solvent enters the channel of the microfluidic chip from a sample inlet; under the control of the positioning table, the laser emitted by the laser can be accurately focused on the organic solvent in the microfluidic chip after passing through the light path, the Raman signal of the organic solvent is collected through the detection light path and transmitted to the spectrum analysis software in the host computer for processing, so that the Raman spectrum detection of the organic solvent is realized; through the optical fiber coupler, the external Raman reflection signal can also be introduced into the detection light path in the instrument, and then the detection of the sample outside the instrument is completed; the application has the characteristics of low sample consumption and portability, and can meet the demand of in-situ detection.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of spectral analysis, in particular to an organic solvent Raman spectrum detection system integrated with a microfluidic chip. BACKGROUND

[0002] In the past few decades, microfluidic technology and Raman spectrum technology have made great progress. Raman spectrum technology is a spectrum technology based on Raman scattering principle, which obtains the structure and composition information of a substance by measuring the frequency shift of scattered light of the sample. Compared with traditional spectrum technology, Raman spectrum technology has the advantages of non-destructive, high sensitivity and rapidity. In the field of liquid composition detection, Raman spectrum technology is widely used in food safety, drug analysis, environmental monitoring. By analyzing the Raman spectrum of the sample, the composition and concentration of different compounds can be accurately identified, which provides an important analysis means for the research in the fields of chemistry and biology. Microfluidic technology is a method of using micro fluid control technology for experiment and analysis, which has the advantages of less reagent consumption, fast reaction speed and simple operation, and is usually used to realize miniaturization, high efficiency of chemical analysis, biological analysis and experimental platform. Microfluidic technology combined with Raman spectrum technology not only can accurately control and analyze the sample, but also has very high resolution and sensitivity to realize the high sensitivity and high selectivity detection of heavy metal ions in trace samples.

[0003] However, in the existing Raman spectrum detection equipment, it is not convenient to sample the sample to be detected during spectrum detection, and there are problems such as complex assembly of spectrum projection mechanism and cumbersome maintenance. Because the size and shape of the microfluidic chip are special, when the fluid in it is used as the sample to be detected, the general Raman spectrometer is difficult to analyze it conveniently and effectively. In addition, due to the large volume and inconvenient movement of the large Raman spectrometer, it is often impossible to carry out on-site detection, and such instrument is highly professional and difficult to operate, which limits its application in more fields. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides an organic solvent Raman spectrum detection system integrated with a microfluidic chip.

[0005] The technical scheme of the present application is as follows:

[0006] An organic solvent Raman spectrum detection system integrated with a microfluidic chip, comprising a Raman spectrum excitation detection light path, a microfluidic chip, a positioning table, a peristaltic pump, a power supply, an instrument shell and spectrum analysis software.

[0007] The microfluidic chip is bonded by polydimethylsiloxane and glass slides after plasma treatment;

[0008] The spectral analysis software comprises Raman spectrum data preprocessing, feature extraction and classification identification; the Raman spectrum data preprocessing specifically comprises: applying an adaptive iterative reweighted penalized least squares method to deduct the obtained Raman spectrum from a spectrum baseline, remove noise and retain effective information of the Raman spectrum; the feature extraction specifically comprises: using a peak searching algorithm to screen feature peaks at specific wave number positions from the preprocessed spectrum data; the classification identification specifically comprises: matching the spectrum data to a database for identification through a search algorithm, and then performing qualitative or quantitative analysis on unknown organic solvent samples; the database comprises spectrum characteristics and physical and chemical property information of known compounds;

[0009] The instrument shell comprises an aluminum alloy plate, a cover plate, a surrounding plate and a partition plate, the surrounding plate, the partition plate and the cover plate are all made of acrylic material; the surrounding plate is fixed to the bottom aluminum alloy plate by screws, the partition plate is vertically arranged in the middle of the surrounding plate and has the same distance from the two surrounding plates and is fixed to the surrounding plate by a sliding rail; the upper end of the surrounding plate is provided with a sliding rail, and the cover plate is covered on the surrounding plate by the sliding rail;

[0010] A light transmission hole is arranged on the partition plate; a sample inlet, a sample outlet and a fiber coupler opening are arranged on the surrounding plate;

[0011] Pull handles are arranged on both sides of the aluminum alloy plate and are fixed to the aluminum alloy plate by screws;

[0012] The Raman spectrum excitation detection light path comprises a laser, an objective lens, a converging lens, a light splitting prism, a filter, an optical microhole, a first reflector, a second reflector, a grating, a CCD module and a fiber coupler; the fiber coupler is fixed in the fiber coupler opening of the surrounding plate, the base of the laser, the objective lens, the converging lens, the light splitting prism, the filter, the optical microhole, the first reflector, the second reflector and the grating are fixed to the aluminum alloy plate by screws; the fiber coupler, the light splitting prism and the laser are sequentially arranged on the same straight line, the microfluidic chip, the objective lens, the light splitting prism, the light transmission hole on the partition plate, the filter, the converging lens, the optical microhole and the first reflector are sequentially arranged on the same straight line, the first reflector, the second reflector and the grating are arranged at an angle of 45° with respect to incident light, and the CCD module is arranged at an angle of 90° with respect to incident light;

[0013] The laser has a power of 100 mW and is used to generate 532 nm green laser; the CCD module is connected to an upper computer through a data line by being fixed to a USB interface of the instrument shell;

[0014] The peristaltic pump is connected to two hoses, one of which is connected to the microfluidic chip, and the other of which is arranged outside the instrument through the sample inlet and is used to contain an organic solvent in a sampling test tube; the adjusting button of the peristaltic pump is fixed to the instrument shell and is used to adjust the flux of the sample during detection;

[0015] The positioning table is composed of a manually adjusted XY two-dimensional micro displacement platform and a chip clamp, and is fixed by a screw;

[0016] The power supply is a peristaltic pump and a laser power supply, and the power supply switch of the power supply is fixed at the bottom of the instrument shell.

[0017] The beneficial effects generated by the above technical scheme are:

[0018] The application provides an organic solvent Raman spectrum detection system integrated with a microfluidic chip, and specifically has the following beneficial effects:

[0019] (1) The external sample is driven by the peristaltic pump to enter the microfluidic chip from the sample inlet, and the real-time sample feeding of the to-be-detected object is facilitated during spectrum detection.

[0020] (2) The microfluidic chip is detected from the bottom surface, the pipeline for conveying the sample does not contact the detection light path, the detection effect is not affected, and the design of the inlet and outlet of the channel in the microfluidic chip is not limited.

[0021] (3) The design of the pull-out cover plate facilitates the replacement of different types of microfluidic chips, and facilitates assembly, use and equipment maintenance.

[0022] (4) The positioning table for fixing the microfluidic chip is designed, which can be suitable for various microfluidic chips, and is beneficial to adjusting the position of the microfluidic chip in the XY plane, facilitating accurate focusing of the laser detection light source on the sample in the microfluidic chip.

[0023] (5) In addition, the portable design and the existence of the power supply make the instrument can be used for sampling detection in the field environment, such as monitoring tap water, surface water, industrial wastewater and various water quality samples, to realize real-time monitoring and analysis. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 FIG. 1 is a schematic structural diagram of an instrument shell in an organic solvent Raman spectrum detection system integrated with a microfluidic chip according to the application;

[0025] In the figure, 1 is an aluminum alloy plate, 2 is a coaming, 3 is a partition plate, 17 is a cover plate, 19 is a pull handle, 20 is a sample inlet, 21 is a sample outlet, 22 is a light transmission hole, 23 is a power switch, 24 is an adjusting knob, 25 is a USB interface, and 26 is a fiber coupler.

[0026] Figure 2 FIG. 2 is a top view of the inside of the organic solvent Raman spectrum detection system integrated with the microfluidic chip according to the application;

[0027] In the figure, 4-peristaltic pump, 5-positioning table, 6-microfluidic chip, 7-laser, 8-spectroscopic prism, 9-objective lens, 10-filter, 11-converging lens, 12-optical micro-hole, 13-first mirror, 14-second mirror, 15-grating, 16-CCD module, 18-power supply;

[0028] Figure 3 Raman detection spectrum of different organic solvents;

[0029] Figure 4 Raman detection spectrum of the same organic solvent with different concentrations;

[0030] Figure 5 Linear curve between ethanol concentration and actual concentration in Raman spectrum detection. DETAILED DESCRIPTION

[0031] The specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate the present application, but are not used to limit the scope of the present application.

[0032] An integrated microfluidic chip organic solvent Raman spectrum detection system, comprising a Raman spectrum excitation detection light path, a microfluidic chip, a positioning table, a peristaltic pump, a power supply, an instrument shell and spectrum analysis software;

[0033] The microfluidic chip 6 is bonded by polydimethylsiloxane and glass slides after plasma treatment;

[0034] The spectrum analysis software includes Raman spectrum data preprocessing, feature extraction and classification identification; the Raman spectrum data preprocessing specifically is: applying adaptive iterative reweighted penalized least squares method, deducting the obtained Raman spectrum from the spectrum baseline, removing noise and retaining effective information of the Raman spectrum; the feature extraction specifically is: using peak searching algorithm to screen out characteristic peaks at specific wave number positions from the preprocessed spectrum data; the classification identification specifically is: matching the spectrum data to the database for identification through a search algorithm, and then qualitatively or quantitatively analyzing unknown organic solvent samples; the database contains spectral characteristics and physical and chemical property information of known compounds;

[0035] The instrument shell comprises an aluminum alloy plate 1, a cover plate 17, a surrounding plate 2 and a partition plate 3, all of which are made of acrylic material; the surrounding plate 2 is fixed to the bottom aluminum alloy plate 1 by screws, the partition plate 3 is vertically arranged in the middle of the surrounding plate 2, and the distance from the two sides of the surrounding plate 2 is the same, which is 18 cm, and the partition plate 3 is fixed to the surrounding plate 2 by a slide rail; the upper end of the surrounding plate 2 is provided with a slide rail, and the cover plate 17 is covered on the surrounding plate 2 through the slide rail; the cover plate 17 is moved along the slide rail to open and close the instrument shell, which is convenient for replacing and maintaining the internal devices. In the embodiment, the aluminum alloy plate is 45 cm x 30 cm, the cover plate is 36 cm x 25 cm, and the surrounding plate and the partition plate are 25 cm x 10 cm;

[0036] A light transmission hole 22 with a diameter of 1 cm is arranged on the partition plate 3; the Raman reflection signal is conveniently transmitted from the left side of the partition plate to the right side of the light path, and stray light refracted in the instrument can be filtered out. The surrounding plate 2 is provided with a sample inlet 20, a sample outlet 21 and an optical fiber coupler opening;

[0037] Pulling handles 19 are arranged on both sides of the aluminum alloy plate 1 and are fixed to the aluminum alloy plate 1 by screws;

[0038] The Raman spectrum excitation detection light path comprises a laser 7, an objective lens 9, a converging lens 11, a light splitting prism 8, a filter 10, an optical micro-hole 12, a first mirror 13, a second mirror 14, a grating 15, a CCD module 16 and an optical fiber coupler 26; wherein the optical fiber coupler 26 is fixed in the optical fiber coupler opening of the surrounding plate, the bases of the laser 7, the objective lens 9, the converging lens 11, the light splitting prism 8, the filter 10, the optical micro-hole 12, the first mirror 13, the second mirror 14, the grating 15 and the CCD module 16 are fixed to the aluminum alloy plate 1 by screws; the optical fiber coupler 26, the light splitting prism 8 and the laser 7 are sequentially arranged on the same straight line, the microfluidic chip 6, the objective lens 9, the light splitting prism 8, the light transmission hole 22 on the partition plate, the filter 10, the converging lens 11, the optical micro-hole 12 and the first mirror 13 are sequentially arranged on the same straight line, the first mirror 13, the second mirror 14 and the grating 15 are arranged at an angle of 45° with the incident light, and the CCD module 16 is arranged at an angle of 90° with the incident light;

[0039] The laser 7 has a power of 100 mW and is used to generate 532 nm green laser; the CCD module 16 adopts Sony ILX511, and is connected to an upper computer through a data line through a USB interface 25 fixed to the instrument shell, so as to not only supply power for the CCD module, but also transmit the received spectrum signal to the spectrum analysis software in the upper computer for processing.

[0040] The peristaltic pump 4 is connected to two flexible tubes, one of which is connected to the microfluidic chip, and the other passes through the sample inlet and is placed outside the instrument in a sampling tube containing organic solvent; the adjustment knob 24 of the peristaltic pump is fixed to the instrument housing and is used to adjust the sample throughput during detection.

[0041] The positioning stage 5 consists of a manually adjustable XY two-dimensional micro-displacement platform and a chip fixture, which are fixed by screws; the chip fixture is suitable for microfluidic chips with a size not exceeding 25mm×75mm.

[0042] The power supply 18 supplies power to the peristaltic pump and the laser, and the power switch 23 of the power supply is fixed to the bottom of the instrument housing.

[0043] Example 1: As per the instruction manual Figure 1 , Figure 2 As shown, an organic solvent Raman spectroscopy detection system with integrated microfluidic chip includes a Raman spectroscopy excitation-detection optical path, a positioning stage 5, a peristaltic pump 4, a mobile power supply 18, an instrument housing, and spectral analysis software. During Raman spectroscopy detection, a laser is generated by laser 7 and focused into a channel in microfluidic chip 6 by beam splitter prism 8 and objective lens 9. The organic solvent to be detected enters the microfluidic chip through inlet 20 driven by a peristaltic pump. By pre-adjusting the positioning stage of the microfluidic chip, the excitation light emitted by the laser is accurately focused onto the sample in the microfluidic chip after passing through the optical prism and objective lens. The Raman signal generated by the excitation of the organic solvent is collected by objective lens 9, passes through beam splitter prism 8, and enters the filter 10 on the right side through the light-passing hole 22 reserved in partition 3 to filter out Rayleigh scattering light. Then, it passes through converging lens 11 and optical micro-aperture 12 and illuminates the first reflecting mirror 13. The reflected light is dispersed into a series of beams of different wavelengths after passing through grating 15, forming a spectrum. The spectrum is received by CCD detection module 16 after passing through second reflecting mirror 14 and transmitted to the spectral analysis software in the host computer for processing, thereby realizing the Raman spectral detection of organic solvent.

[0044] Example 2: Compared with the organic solvent Raman spectroscopy detection system with integrated microfluidic chip described in Example 1, Example 2 differs in that it provides a method for detecting external Raman reflection signals.

[0045] As per the instruction manual Figure 2 As shown, the external Raman reflection signal can be introduced into the beam splitter 8 inside the instrument through the fiber optic coupler 26. After passing through the beam splitter 8, the Raman signal enters the right detection optical path through the light-passing hole 22 reserved in the partition 3. The subsequent propagation optical path is consistent with the right optical path of the partition 3 in Example 1. Finally, the spectral signal is received by the CCD module 16 and transmitted to the host computer for processing and analysis, thereby completing the detection of the external sample of the instrument and greatly expanding the application range of the system.

[0046] Example 3: As per the instruction manual Figure 3 As shown, solutions of methanol, ethanol, toluene, and acetone were passed into a microfluidic chip for Raman spectroscopy detection. After data processing, the spectral signals were compared with spectra in a database to analyze the type of unknown organic solvent. (See attached instruction manual.) Figure 4 The image shows the spectral signals obtained by Raman spectroscopy detection when ethanol solutions of different concentrations are passed through a microfluidic chip; as per the instruction manual. Figure 5 As shown, the linear relationship between the ethanol concentration detected by Raman spectroscopy and the actual concentration is as high as 96.3%. These data indicate that this system can effectively perform qualitative and quantitative analysis of organic solvent samples, and has high resolution and sensitivity.

[0047] The above description is merely a preferred embodiment of this disclosure and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in the embodiments of this disclosure is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in the embodiments of this disclosure.

Claims

1. An integrated microfluidic chip-based organic solvent Raman spectroscopy detection system, characterized in that, It comprises a Raman spectrum excitation detection light path, a microfluidic chip, a positioning table, a peristaltic pump, a power supply, an instrument shell and spectrum analysis software. The microfluidic chip is bonded by polydimethylsiloxane and a glass slide after plasma treatment. The instrument shell comprises an aluminum alloy plate, a cover plate, a surrounding plate and a partition plate, the surrounding plate, the partition plate and the cover plate are made of acrylic material, the surrounding plate at the periphery is fixed to the aluminum alloy plate at the bottom through screws, the partition plate is vertically arranged in the middle of the surrounding plate and has the same distance from the surrounding plates at both sides and is fixed to the surrounding plate through a sliding rail, the upper end of the surrounding plate is provided with a sliding rail and the cover plate is covered on the surrounding plate through the sliding rail. A light passing hole is arranged on the partition plate and sample inlet and outlet and an optical fiber coupler opening are arranged on the surrounding plate. Pulling handles are arranged on the two sides of the aluminum alloy plate and are fixed to the aluminum alloy plate through screws. The laser power is 100 mW and is used for generating 532 nm green laser, and the CCD module is connected to the upper computer through a data line through a USB interface fixed to the instrument shell. The peristaltic pump is connected to two hoses, one of which is connected to the microfluidic chip and the other of which is arranged in a sampling test tube containing an organic solvent outside the instrument through the sample inlet, and the adjusting button of the peristaltic pump is fixed to the instrument shell and is used for adjusting the flux of the sample during detection. 2.The integrated microfluidic chip-based organic solvent Raman spectrum detection system of claim 1, wherein, The Raman spectrum excitation detection light path comprises a laser, an objective lens, a converging lens, a light splitting prism, a filter, an optical microhole, a first reflector, a second reflector, a grating, a CCD module and an optical fiber coupler, the optical fiber coupler is fixed in the optical fiber coupler opening of the surrounding plate, the base of the laser, the objective lens, the converging lens, the light splitting prism, the filter, the optical microhole, the first reflector, the second reflector and the grating are fixed to the aluminum alloy plate through screws, the optical fiber coupler, the light splitting prism and the laser are sequentially arranged on the same straight line, the microfluidic chip, the objective lens, the light splitting prism, the light passing hole on the partition plate, the filter, the converging lens, the optical microhole and the first reflector are sequentially arranged on the same straight line, the first reflector, the second reflector and the grating are arranged at an angle of 45° with incident light, and the CCD module is arranged at an angle of 90° with incident light. 3.The integrated microfluidic chip-based organic solvent Raman spectroscopy detection system of claim 1, wherein, The positioning table is composed of a manually adjusted XY two-dimensional micro displacement platform and a chip clamp and is fixed through screws. 4.The integrated microfluidic chip-based organic solvent Raman spectrum detection system of claim 1, wherein, The power supply is used for supplying power to the peristaltic pump and the laser, and the power supply switch is fixed to the bottom of the instrument shell.

5. The integrated microfluidic chip-based organic solvent Raman spectroscopic detection system according to claim 1, wherein, The spectrum analysis software comprises Raman spectrum data preprocessing, feature extraction and classification identification, the Raman spectrum data preprocessing specifically comprises: applying an adaptive iterative reweighted penalized least squares method to deduct the obtained Raman spectrum from a spectrum baseline, remove noise and retain effective information of the Raman spectrum, the feature extraction specifically comprises: using a peak searching algorithm to screen feature peaks at specific wave number positions from the preprocessed spectrum data, and the classification identification specifically comprises: matching the spectrum data to a database through a search algorithm for identification, thereby performing qualitative or quantitative analysis on unknown organic solvent samples, and the database contains spectral characteristics and physical and chemical property information of known compounds.

Images