A portable raman spectrum-based cerebrospinal fluid chloride quantitative detection method

Abstract

The present application relates to a kind of portable raman spectrum-based cerebrospinal fluid chloride quantitative detection method, comprising the following steps: S1: preparation silver nano colloidal solution A;S2: preparation titanium dioxide super-hydrophobic support substrate;S3: silver nano colloidal solution A is mixed with potassium iodide aqueous solution, obtain mixed solution D;S4: sodium chloride blank sample is mixed with mixed solution D to obtain mixed solution E, mixed solution E is added on titanium dioxide super-hydrophobic support substrate, the surface-enhanced raman spectroscopy of mixed solution E is detected, the relationship curve of raman characteristic peak intensity and sodium chloride concentration is established;S5: the cerebrospinal fluid to be measured is mixed with mixed solution D to obtain mixed solution F, mixed solution F is added on titanium dioxide super-hydrophobic support substrate, the surface-enhanced raman spectroscopy of mixed solution F is detected, and the concentration of sodium chloride in the cerebrospinal fluid to be measured is calculated.The method is simple in operation, low in cost, short in time consumption, and can be used for the rapid detection of the concentration of chloride in cerebrospinal fluid.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of clinical application of Raman spectroscopy, and particularly relates to a cerebrospinal fluid chloride quantitative detection method based on a portable Raman spectrum. BACKGROUND

[0002] Cerebrospinal fluid is a colorless and transparent liquid existing in the ventricle and subarachnoid space. When the content of chemical components in the cerebrospinal fluid changes, it may indicate the occurrence of certain diseases. For example, the increase of the content of chloride in the cerebrospinal fluid may indicate chronic renal insufficiency, nephritis, uremia, etc., and the decrease of the content may indicate bacterial meningitis.

[0003] The commonly used chloride detection methods, such as ion electrode method, have high detection precision, but the operation is complicated, and the detection time is generally more than 30 minutes, so the detection time is relatively long.

[0004] Raman spectroscopy is a simple, rapid and non-destructive detection technology, which has been widely used in the field of life science. Most commonly used Raman spectrometers are large Raman spectrometers with high detection precision and high price, which are difficult to carry and are not suitable for on-site detection. The portable Raman spectrometer is small in size and can well adapt to different detection environments, and is more suitable for on-site rapid detection. However, the sensitivity of the portable Raman spectrometer is relatively low, which cannot meet the detection requirements. Combined with surface-enhanced Raman spectroscopy technology, the detection sensitivity and signal-to-noise ratio can be improved. SUMMARY

[0005] In order to solve the above problems in the prior art, the application provides a cerebrospinal fluid chloride quantitative detection method based on a portable Raman spectrum. The technical problems to be solved by the application are solved by the following technical scheme:

[0006] The application provides a cerebrospinal fluid chloride quantitative detection method based on a portable Raman spectrum, which comprises the following steps:

[0007] S1: preparing a silver nanocolloid solution A;

[0008] S2: preparing a titanium dioxide super-hydrophobic support substrate;

[0009] S3: mixing the silver nanocolloid solution A with a potassium iodide aqueous solution to obtain a mixed solution D;

[0010] S4: mixing a sodium chloride blank sample with the mixed solution D to obtain a mixed solution E, dropping the mixed solution E on the titanium dioxide super-hydrophobic support substrate, detecting the surface-enhanced Raman spectrum of the mixed solution E on the titanium dioxide super-hydrophobic support substrate, and establishing a relationship curve between the Raman characteristic peak intensity and the sodium chloride concentration;

[0011] S5: mixing the cerebrospinal fluid sample to be tested with the mixed solution D to obtain a mixed solution F, dropping the mixed solution F on the titanium dioxide super-hydrophobic support substrate, detecting the surface-enhanced Raman spectrum of the mixed solution F on the titanium dioxide super-hydrophobic support substrate, and calculating the concentration of sodium chloride in the cerebrospinal fluid sample to be tested according to the surface-enhanced Raman spectrum of the mixed solution F and the relationship curve.

[0012] In one specific embodiment, step S4 comprises:

[0013] S401: preparing sodium chloride aqueous solutions with different concentrations respectively to obtain a plurality of sodium chloride solution blank samples with different concentrations;

[0014] S402: mixing the mixed solution D with the plurality of sodium chloride solution blank samples with different concentrations respectively according to a volume ratio of 1:1-4 to obtain a plurality of mixed solutions E with different concentrations;

[0015] S403: dropping the plurality of mixed solutions E with different concentrations on a plurality of titanium dioxide super-hydrophobic support substrates respectively, and detecting the plurality of drops of the plurality of mixed solutions E with different concentrations on the plurality of titanium dioxide super-hydrophobic support substrates using a portable Raman spectrometer to obtain the surface-enhanced Raman spectrum of the plurality of mixed solutions E with different concentrations;

[0016] S404: calculating the Raman characteristic peak intensity of the surface-enhanced Raman spectrum of the plurality of mixed solutions E with different concentrations according to the surface-enhanced Raman spectrum of the plurality of mixed solutions E with different concentrations, and determining the relationship curve of the Raman characteristic peak intensity and the concentration of sodium chloride.

[0017] In one specific embodiment, step S5 comprises:

[0018] S501: mixing the mixed solution D with the cerebrospinal fluid sample to be tested according to a volume ratio of 1:1-4 to obtain a mixed solution F;

[0019] S502: dropping the mixed solution F on the titanium dioxide super-hydrophobic support substrate, and detecting the drop of the mixed solution F on the titanium dioxide super-hydrophobic support substrate using a portable Raman spectrometer to obtain the surface-enhanced Raman spectrum of the mixed solution F;

[0020] S503: determining the Raman characteristic peak intensity of the surface-enhanced Raman spectrum of the mixed solution F according to the surface-enhanced Raman spectrum of the mixed solution F;

[0021] S504: determining the concentration of sodium chloride in the cerebrospinal fluid sample to be tested according to the Raman characteristic peak intensity of the surface-enhanced Raman spectrum of the mixed solution F and the relationship curve.

[0022] In one specific embodiment, step S1 comprises:

[0023] The silver nitrate aqueous solution is mixed with deionized water and added to the container, stirred and continuously heated to boiling, then the sodium citrate aqueous solution is added and stirred, the heating is stopped after the reaction is completed, the stirring is stopped after cooling to room temperature, and the silver nanocolloid solution A is obtained; the volume ratio of the silver nitrate aqueous solution, the deionized water and the sodium citrate aqueous solution is 1:9:0.1-1.

[0024] In one specific embodiment, the diameter of the silver nanoparticles in the silver nanocolloid solution A is 30-100 nm.

[0025] In one specific embodiment, step S2 comprises:

[0026] S201: 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane is added to anhydrous ethanol to prepare a mixed solution B;

[0027] S202: two different sizes of titanium dioxide nanoparticles are mixed in a mass ratio of 1:1 and then added to the mixed solution B to prepare a titanium dioxide super-hydrophobic reagent C;

[0028] S203: the titanium dioxide super-hydrophobic reagent C is coated on a substrate and dried to obtain a titanium dioxide super-hydrophobic support substrate.

[0029] In one specific embodiment, the volume ratio of 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane to anhydrous ethanol in the mixed solution B is 1:50-200.

[0030] In one specific embodiment, the diameter of the titanium dioxide nanoparticles is 10-150 nm.

[0031] In one specific embodiment, step S3 comprises:

[0032] S301: the silver nanocolloid solution A is centrifuged and concentrated by 5-20 times to obtain a concentrated silver nanocolloid solution;

[0033] S302: the concentrated silver nanocolloid solution and a potassium iodide aqueous solution are mixed, and after standing at room temperature, a mixed solution D is obtained.

[0034] In one specific embodiment, in steps S4 and S5, the detection conditions of the surface-enhanced Raman spectrum are as follows: the laser wavelength is 785 nm, the power is 10%-50% of the maximum power of a portable Raman spectrometer, and the integration time is 1-3 s.

[0035] Compared with the prior art, the present application has the following beneficial effects:

[0036] The application provides a portable Raman spectrum-based cerebrospinal fluid chloride quantitative detection method, which quantitatively detects chloride by using a portable Raman spectrometer and a surface enhanced Raman spectrum technology, utilizes the color change of droplets caused by the aggregation effect of silver nanocolloid solution A mixed with different concentrations of chloride to affect the laser transmittance, causes the change of the intensity of the corresponding characteristic peak of the titanium dioxide support substrate, establishes a chloride concentration detection model in combination with the portable Raman spectrometer and the change of the SERS spectrum peak intensity, and realizes the rapid quantitative detection of the chloride component in the cerebrospinal fluid. The method is simple in operation, low in cost and short in time consumption, and can be used for the rapid detection of the chloride concentration of the cerebrospinal fluid sample. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 is a step schematic diagram of a portable Raman spectrum-based cerebrospinal fluid chloride quantitative detection method provided by an embodiment of the application;

[0038] Figure 2 is a color comparison diagram of droplets after silver nanocolloid is mixed with different concentrations of sodium chloride in the portable Raman spectrum-based cerebrospinal fluid chloride quantitative detection method provided by the embodiment of the application;

[0039] Figure 3 is a color comparison diagram of droplets before and after silver nanocolloid is mixed with cerebrospinal fluid in the portable Raman spectrum-based cerebrospinal fluid chloride quantitative detection method provided by the embodiment of the application;

[0040] Figure 4 is a Raman spectrum diagram of the titanium dioxide super-hydrophobic support substrate provided by the embodiment of the application;

[0041] Figure 5 is a Raman spectrum diagram of the mixed solution E provided by the embodiment of the application;

[0042] Figure 6 is a Raman spectrum diagram of the mixed solution E provided by the embodiment of the application;

[0043] Figure 7 is a relationship curve diagram of the Raman characteristic peak intensity and the sodium chloride concentration provided by the embodiment of the application;

[0044] Figure 8 is a surface enhanced Raman spectrum diagram of the mixed solution F provided by the embodiment of the application;

[0045] Figure 9 is a Raman spectrum diagram of the mixed solution F provided by the embodiment of the application. DETAILED DESCRIPTION

[0046] The application will be further described in detail below in combination with specific embodiments, but the embodiments of the application are not limited thereto.

[0047] Embodiment one

[0048] See Figure 1 A portable Raman spectrum-based cerebrospinal fluid chloride quantitative detection method, comprising the following steps:

[0049] S1: preparing a silver nanocolloid solution A. Specifically, a silver nitrate aqueous solution is mixed with deionized water and added to a container, stirring and continuously heating to boiling, then adding a sodium citrate aqueous solution to continue stirring, stopping heating after complete reaction, stopping stirring after cooling to room temperature to obtain the silver nanocolloid solution A. The volume ratio of the silver nitrate aqueous solution, the deionized water and the sodium citrate aqueous solution is 1:9:0.1-1. The diameter of the silver nanoparticles in the silver nanocolloid solution A is 30-100 nm.

[0050] Preferably, the concentration of the silver nitrate aqueous solution is 10×10 -3 mol / L, the concentration of the sodium citrate aqueous solution is 1%wt, and the silver nanocolloid solution A is stored at 4°C under low-temperature conditions.

[0051] S2: preparing a titanium dioxide super-hydrophobic support substrate. Specifically, step S2 comprises S201-S203:

[0052] S201: adding 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane to anhydrous ethanol to prepare a mixed solution B;

[0053] S202: mixing two different sizes of titanium dioxide nanoparticles in a mass ratio of 1:1 and adding to the mixed solution B to prepare a titanium dioxide super-hydrophobic reagent C. Specifically, 5-20 g of the mixed titanium dioxide nanoparticles are added to the mixed solution B and magnetically stirred until complete reaction to obtain the titanium dioxide super-hydrophobic reagent C;

[0054] S203: coating the titanium dioxide super-hydrophobic reagent C on a substrate, drying to obtain the titanium dioxide super-hydrophobic support substrate.

[0055] The volume ratio of 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane and anhydrous ethanol in the mixed solution B is 1:50-200. The diameter of the titanium dioxide nanoparticles is 10-150 nm.

[0056] S3: mixing the silver nanocolloid solution A with a potassium iodide aqueous solution to obtain a mixed solution D. Specifically, step S3 comprises S301-S302:

[0057] S301: centrifuging the silver nanocolloid solution A to concentrate 5-20 times to obtain a concentrated silver nanocolloid solution;

[0058] S302: mixing the concentrated silver nanocolloid solution and the potassium iodide aqueous solution, and obtaining a mixed solution D after standing at room temperature. Preferably, the concentration of the potassium iodide aqueous solution is 1 x 10 -3 mol / L.

[0059] S4: mixing the sodium chloride blank sample with the mixed solution D to obtain a mixed solution E, dropping the mixed solution E on the titanium dioxide super-hydrophobic support substrate, detecting the surface-enhanced Raman spectrum of the mixed solution E on the titanium dioxide super-hydrophobic support substrate, and establishing a relationship curve (standard curve) of the Raman characteristic peak intensity and the sodium chloride concentration.

[0060] Specifically, step S4 includes S401-S404:

[0061] S401: preparing sodium chloride aqueous solutions with different concentrations respectively to obtain a plurality of sodium chloride solution blank samples with different concentrations;

[0062] S402: mixing the mixed solution D with the plurality of sodium chloride solution blank samples with different concentrations respectively according to a volume ratio of 1:1-4 to obtain a plurality of mixed solutions E with different concentrations;

[0063] S403: dropping the plurality of mixed solutions E with different concentrations on a plurality of titanium dioxide super-hydrophobic support substrates respectively, and detecting the droplets of the plurality of mixed solutions E with different concentrations on the plurality of titanium dioxide super-hydrophobic support substrates using a portable Raman spectrometer to obtain the surface-enhanced Raman spectra of the plurality of mixed solutions E with different concentrations;

[0064] S404: calculating the Raman characteristic peak intensity of the surface-enhanced Raman spectra of the plurality of mixed solutions E with different concentrations according to the surface-enhanced Raman spectra of the plurality of mixed solutions E with different concentrations, and determining the relationship curve (standard curve) of the Raman characteristic peak intensity and the sodium chloride concentration.

[0065] Specifically, the aggregation effect of the silver nanocolloid solution A mixed with different concentrations of chlorides will cause the color change of the solution, which will lead to the change of the laser transmittance of the droplets, and further cause the change of the corresponding characteristic peak intensity of the titanium dioxide support substrate. The intensity of the corresponding Raman characteristic peak of the titanium dioxide support substrate obtained by detecting the sodium chloride blank solution with different concentrations decreases with the increase of the sodium chloride concentration, and the standard curve of the sodium chloride concentration and the characteristic peak intensity can be established.

[0066] S5: mixing the cerebrospinal fluid sample to be tested with the mixed solution D to obtain a mixed solution F, dropping the mixed solution F on the titanium dioxide super-hydrophobic support substrate, detecting the surface-enhanced Raman spectrum of the mixed solution F on the titanium dioxide super-hydrophobic support substrate, and calculating the concentration of sodium chloride in the cerebrospinal fluid sample to be tested according to the surface-enhanced Raman spectrum of the mixed solution F and the relationship curve between the Raman characteristic peak intensity and the concentration of sodium chloride. Specifically, step S5 includes S501-S504:

[0067] S501: mixing the mixed solution D with the cerebrospinal fluid sample to be tested at a volume ratio of 1:1-4 to obtain a mixed solution F;

[0068] S502: dropping the mixed solution F on the titanium dioxide super-hydrophobic support substrate, and detecting the droplet of the mixed solution F on the titanium dioxide super-hydrophobic support substrate using a portable Raman spectrometer to obtain the surface-enhanced Raman spectrum of the mixed solution F;

[0069] S503: determining the Raman characteristic peak intensity of the surface-enhanced Raman spectrum of the mixed solution F according to the surface-enhanced Raman spectrum of the mixed solution F;

[0070] S504: determining the concentration of sodium chloride in the cerebrospinal fluid sample to be tested according to the Raman characteristic peak intensity of the surface-enhanced Raman spectrum of the mixed solution F and the standard curve.

[0071] Specifically, the aggregation effect of the silver nanocolloid solution A mixed with different concentrations of chloride will cause a change in the color of the solution, which will lead to a change in the laser transmittance of the droplet, and then cause a change in the corresponding characteristic peak intensity of the titanium dioxide support substrate. By detecting different concentrations of sodium chloride blank solution, the intensity of the corresponding Raman characteristic peak of the titanium dioxide support substrate decreases with the increase of the concentration of sodium chloride, and a standard curve of the concentration of sodium chloride and the characteristic peak intensity can be established. When detecting the cerebrospinal fluid of a clinical patient, the same detection method and detection conditions as when detecting the sodium chloride blank solution are used, and the Raman spectrometer is used to detect the Raman spectrum of the clinical cerebrospinal fluid to be tested. After processing the Raman spectrum, the intensity of the Raman characteristic peak of the clinical cerebrospinal fluid to be tested is calculated, and the intensity of the Raman characteristic peak of the clinical cerebrospinal fluid to be tested is substituted into the above standard curve to obtain the concentration of sodium chloride in the cerebrospinal fluid to be tested, thereby realizing the rapid quantitative detection of the chloride component in the cerebrospinal fluid.

[0072] Further, in steps S4 and S5, the detection conditions of the surface-enhanced Raman spectrum are as follows: the laser wavelength is 785 nm, the power is 10%-50% of the maximum power of the portable Raman spectrometer, and the integration time is 1-3 s.

[0073] The embodiment provides a portable Raman spectrum-based cerebrospinal fluid chloride quantitative detection method, which quantitatively detects chloride by using a portable Raman spectrometer and a surface enhanced Raman spectrum technology, utilizes the droplet color change caused by the aggregation effect of silver nano colloidal solution A mixed with different concentrations of chloride to affect the laser transmittance, causes the intensity change of a corresponding characteristic peak of a titanium dioxide support substrate, establishes a chloride concentration detection model by combining the portable Raman spectrometer and the SERS spectrum peak intensity change, and realizes rapid quantitative detection of the chloride component in the cerebrospinal fluid. The mixed solution D and the titanium dioxide super-hydrophobic support substrate can be prepared in advance, and during clinical detection, only 10-30 μL of a mixed solution F of the clinical cerebrospinal fluid sample to be detected and the mixed solution D needs to be added dropwise on the titanium dioxide super-hydrophobic support substrate, so that the whole test process can be completed, and the detection time is only 1-5 min. Different concentrations of sodium chloride blank solutions are detected by the method, the intensity of the corresponding Raman characteristic peak of the titanium dioxide support substrate decreases with the increase of the concentration of the sodium chloride, and a standard curve of the concentration of the sodium chloride and the characteristic peak intensity can be established. When the cerebrospinal fluid of a clinical patient is detected, the rapid quantitative detection of the chloride component in the cerebrospinal fluid can be realized by using the above standard curve. In addition, the color of the droplet changes after the sodium chloride solution with different concentrations is mixed with the concentrated silver nano colloidal solution modified by potassium iodide, and the higher the concentration of the sodium chloride is, the deeper the color is. Therefore, the content of the chloride in the cerebrospinal fluid can be preliminarily judged according to the color change, and the quantitative analysis is further carried out by the portable SERS detection. The method is simple in operation, low in cost and short in time consumption, and can be used for rapid detection of the chloride concentration of the cerebrospinal fluid sample.

[0074] Embodiment two

[0075] The embodiment provides a portable Raman spectrum-based cerebrospinal fluid chloride quantitative detection method based on the embodiment one, and the method comprises the following steps.

[0076] S1: 10*10 -3 mol / L of silver nitrate aqueous solution is mixed with deionized water and added into a conical flask, heated to boiling under vigorous stirring, then 1%wt of sodium citrate aqueous solution is injected to continue stirring until complete reaction, and the stirring is stopped after cooling to room temperature to obtain silver nano colloidal solution A. The silver nano colloidal solution A is stored under 4 DEG C low-temperature condition in a sealed state. The volume ratio of the silver nitrate aqueous solution, the deionized water and the sodium citrate aqueous solution in the silver nano colloidal solution A is 1:9:0.3.

[0077] S2: 1H,1H,2H,2H-perfluorooctyltriethoxysilane is added to anhydrous ethanol to prepare a solution. The solution is magnetically stirred at room temperature until the reaction is complete, yielding 100 mL of mixed solution B. Two types of titanium dioxide nanoparticles of different sizes are mixed at a 1:1 mass ratio. 12 g of this mixture is added to mixed solution B and magnetically stirred until the reaction is complete, yielding titanium dioxide superhydrophobic reagent C. An appropriate amount of titanium dioxide superhydrophobic reagent C is drop-coated or spray-coated onto a substrate. The substrate is placed horizontally until the titanium dioxide superhydrophobic reagent C air-dries naturally, resulting in a titanium dioxide superhydrophobic support substrate with superhydrophobic properties. The substrate can be a glass sheet, stainless steel plate, silicon wafer, aluminum sheet, copper sheet, or a 3D-printed bowl-shaped array, etc. The volume ratio of 1H,1H,2H,2H-perfluorooctyltriethoxysilane to anhydrous ethanol in mixed solution B is 1:99.

[0078] Following the method in step S2, titanium dioxide nanoparticles of 10–25 nm, 60 nm, 100 nm, and 150 nm were mixed in pairs to obtain six different titanium dioxide superhydrophobic support substrates. The Raman spectra of these six different titanium dioxide superhydrophobic support substrates were directly detected using a portable Raman spectrometer. The original Raman spectra were then processed to obtain the following results: Figure 4 The Raman spectrum shown indicates that the C of the titanium dioxide superhydrophobic reagent prepared by mixing titanium dioxide particles of different sizes has a value of 396 cm⁻¹. -1 514cm -1 637cm -1 The three common Raman characteristic peaks are observed at [location missing]. However, when titanium dioxide particles with a size of 100 nm are mixed with titanium dioxide particles of other sizes, an additional Raman characteristic peak will be added at 449 cm⁻¹. -1 The Raman characteristic peaks were observed. Therefore, in this embodiment, titanium dioxide nanoparticles with a size of 60 nm and titanium dioxide nanoparticles with a size of 150 nm were mixed at a mass ratio of 1:1.

[0079] S3: After centrifuging and concentrating the silver nanocolloid solution A by 10 times, mix it with 1×10 -3 A mixture of mol / L potassium iodide aqueous solution and a solution of iodide aqueous solution was mixed and allowed to stand at room temperature for 20 min to obtain mixed solution D. The volume ratio of silver nanoparticle colloidal solution to potassium iodide aqueous solution in mixed solution D was 1:1.

[0080] S4: Prepare sodium chloride blank samples with concentrations of 10mM, 20mM, 30mM, 40mM, 50mM, 60mM, 70mM, 80mM, 90mM, 100mM, 110mM, and 120mM. Mix these sodium chloride blank samples with concentrations of 10mM, 20mM, 30mM, 40mM, 50mM, 60mM, 70mM, 80mM, 90mM, 100mM, 110mM, and 120mM respectively with mixed solution D at a volume ratio of 1:1 to obtain mixed solution E. Take 20μL of mixed solution E and drop it onto a titanium dioxide superhydrophobic support substrate and let it stand for 2 min. After standing, observe the color of the droplet of mixed solution E on the titanium dioxide superhydrophobic support substrate and record it with a camera. The color of the droplet of mixed solution E on the titanium dioxide superhydrophobic support substrate is as follows: Figure 2 As shown, a droplet of mixed solution E on a titanium dioxide superhydrophobic support substrate was detected using a portable Raman spectrometer, and the surface-enhanced Raman spectrum of mixed solution E was obtained. The surface-enhanced Raman spectrum of mixed solution E is shown in the figure. Figure 5 As shown.

[0081] Specifically, because the aggregation effect of silver nanoparticle colloidal solution A mixed with chloride of different concentrations causes changes in solution color, when observing and recording droplets on the titanium dioxide superhydrophobic support substrate, droplets containing different concentrations of sodium chloride will show different colors. This color change caused by the aggregation effect leads to changes in the laser transmittance of the droplets, which in turn causes changes in the intensity of the corresponding characteristic peaks on the titanium dioxide support substrate.

[0082] observe Figure 2 The color of droplets in mixed solution E on the titanium dioxide superhydrophobic support substrate is as follows: the droplets without sodium chloride are lighter in color, while the color of silver nanocolloids deepens after the addition of sodium chloride. Furthermore, the color of the droplets gradually deepens as the concentration of sodium chloride increases. Therefore, the concentration of sodium chloride in the solution can be preliminarily determined based on the color of the droplets on the titanium dioxide superhydrophobic support substrate.

[0083] right Figure 5 After baseline correction, the surface-enhanced Raman spectrum of the mixed solution E shown is obtained. Figure 6 The Raman spectrum shown is from Figure 6 It can be observed that as the sodium chloride concentration increases, 637 cm⁻¹ -1 The intensity of the characteristic peak at 396 cm⁻¹ gradually decreases, respectively. -1 514cm -1 and 637cm -1 The peak intensity of the Raman characteristic peak was fitted to the sodium chloride concentration to obtain the following results: Figure 7 The curve showing the relationship between the Raman characteristic peak intensity and sodium chloride concentration (standard curve) is shown. Figure 7The R value of the curve showing the relationship between the intensity of the three Raman characteristic peaks and the sodium chloride concentration. 2 All exceeded 0.98.

[0084] S5: Multiple clinical cerebrospinal fluid samples (CSF1, CSF2, CSF3, CSF4, and CSF5) were mixed with mixed solution D at a volume ratio of 1:1 to obtain multiple mixed solutions F. 20 μL of each mixed solution F was dropped onto multiple titanium dioxide superhydrophobic support substrates and allowed to stand for 2 min. After standing, the color of the droplets of mixed solution F on the multiple titanium dioxide superhydrophobic support substrates was observed and recorded with a camera. The colors of the droplets of mixed solution F on the multiple titanium dioxide superhydrophobic support substrates are as follows: Figure 3 As shown, droplets of mixed solution F on multiple titanium dioxide superhydrophobic support substrates were detected using a portable Raman spectrometer, and surface-enhanced Raman spectra of multiple mixed solutions F were obtained. The surface-enhanced Raman spectra of multiple mixed solutions F are shown below. Figure 8 As shown.

[0085] observe Figure 3 The color of droplets of mixed solution F on a titanium dioxide superhydrophobic support substrate is shown. Before the addition of cerebrospinal fluid, the droplets are lighter in color, while after the addition of cerebrospinal fluid sample, the color of the droplets darkens. The normal chloride content in cerebrospinal fluid is 120-130 mM. If there is a disease, the chloride content in cerebrospinal fluid can change. Therefore, the chloride content in cerebrospinal fluid can be roughly predicted by the color change after cerebrospinal fluid is mixed with nano-silver colloid, so as to make a preliminary judgment on the patient's disease status.

[0086] from Figure 8 637cm can be observed -1 The intensity of the characteristic peak varies considerably at this location, affecting... Figure 8 After baseline correction of the surface-enhanced Raman spectra of the multiple mixed solutions F shown, and according to 637 cm⁻¹, the results were analyzed. -1 The Raman characteristic peak intensities at each location are sorted from smallest to largest to obtain... Figure 9 The Raman spectrum shown will Figure 9 637cm -1 Substituting the Raman characteristic peak intensity at that location into... Figure 7 637cm -1 The concentration of sodium chloride in the clinical cerebrospinal fluid sample can be obtained by calculating the relationship between the Raman characteristic peak intensity and the sodium chloride concentration. After obtaining the clinical cerebrospinal fluid sample, it can be tested quickly and promptly, or stored in a sterile container and kept at -80°C. Before testing, it needs to be thawed at room temperature to prevent changes in the composition of the cerebrospinal fluid sample. In this embodiment, a 396 cm⁻¹ chromatogram was established in step S4. -1 514cm -1 and 637cm -1The relationship curve between the intensity of the three Raman characteristic peaks and the concentration of sodium chloride, in the detection of the clinical cerebrospinal fluid sample, can flexibly select any one of the characteristic peaks of 396cm -1 , 514cm -1 and 637cm -1 to substitute into the relationship curve between the intensity of the Raman characteristic peak and the concentration of sodium chloride for calculation.

[0087] The method provided by the embodiment can quantitatively detect the chloride in the cerebrospinal fluid by using the portable Raman spectrometer and the surface-enhanced Raman spectroscopy technology, and by using the color change of the droplet caused by the aggregation effect of the silver nanocolloid solution A mixed with the chloride of different concentrations to affect the laser transmittance, causing the change of the intensity of the corresponding characteristic peak of the titanium dioxide support substrate. The chloride concentration detection model is established by combining the portable Raman spectrometer and the change of the intensity of the SERS spectrum peak, and the rapid quantitative detection of the chloride component in the cerebrospinal fluid is realized. The mixed solution D and the titanium dioxide super-hydrophobic support substrate can be prepared in advance. During the clinical detection, only 10-30 μL of the mixed solution F of the mixed solution D and the clinical cerebrospinal fluid sample to be detected needs to be added on the titanium dioxide super-hydrophobic support substrate, and the whole test process can be completed, and the detection time is only 1-5 min. By detecting the sodium chloride blank solution of different concentrations by using the method, the intensity of the corresponding Raman characteristic peak of the titanium dioxide support substrate decreases with the increase of the concentration of the sodium chloride, and the standard curve of the concentration of the sodium chloride and the intensity of the characteristic peak can be established. When the cerebrospinal fluid of the clinical patient is detected, the rapid quantitative detection of the chloride component in the cerebrospinal fluid can be realized by using the above standard curve. In addition, the color of the droplet will change after the sodium chloride solution of different concentrations is mixed with the concentrated silver nanocolloid modified by potassium iodide. The higher the concentration of the sodium chloride is, the deeper the color is. Therefore, the content of the chloride in the cerebrospinal fluid can be preliminarily judged by the color change, and the quantitative analysis is further carried out by the portable SERS detection. The method is simple in operation, low in cost and short in time consumption, and can be used for the rapid detection of the chloride concentration of the cerebrospinal fluid sample.

[0088] The above content is a further detailed description of the present application in combination with the specific preferred embodiments, and cannot be regarded as the limitation of the specific implementation of the present application. For ordinary skilled persons in the technical field to which the present application belongs, some simple deductions or substitutions can be made without departing from the concept of the present application, and all of them shall be regarded as the protection scope of the present application.

Claims

1. A portable Raman spectroscopy-based method for quantifying chloride in cerebrospinal fluid, comprising: The method comprises the following steps: S1: preparing a silver nanocolloid solution A; S2: preparing a titanium dioxide super-hydrophobic support substrate; S3: mixing the silver nanocolloid solution A with a potassium iodide aqueous solution to obtain a mixed solution D; S4: mixing a sodium chloride blank sample with the mixed solution D to obtain a mixed solution E, dropping the mixed solution E on the titanium dioxide super-hydrophobic support substrate, detecting the surface-enhanced Raman spectrum of the mixed solution E on the titanium dioxide super-hydrophobic support substrate, and establishing a relationship curve between the Raman characteristic peak intensity and the concentration of sodium chloride; S5: mixing the to-be-tested cerebrospinal fluid sample with the mixed solution D to obtain a mixed solution F, dropping the mixed solution F on the titanium dioxide super-hydrophobic support substrate, detecting the surface-enhanced Raman spectrum of the mixed solution F on the titanium dioxide super-hydrophobic support substrate, and calculating the concentration of sodium chloride in the to-be-tested cerebrospinal fluid sample according to the surface-enhanced Raman spectrum of the mixed solution F and the relationship curve.

2. The method for quantitative detection of chloride in cerebrospinal fluid based on portable Raman spectroscopy according to claim 1, characterized in that, Step S4 comprises: S401: preparing sodium chloride aqueous solutions with different concentrations respectively to obtain a plurality of sodium chloride solution blank samples with different concentrations; S402: mixing the mixed solution D with the plurality of sodium chloride solution blank samples with different concentrations respectively according to a volume ratio of 1:1-4 to obtain a plurality of mixed solutions E with different concentrations; S403: dropping the plurality of mixed solutions E with different concentrations on a plurality of titanium dioxide super-hydrophobic support substrates respectively, and detecting the droplets of the plurality of mixed solutions E with different concentrations on the plurality of titanium dioxide super-hydrophobic support substrates using a portable Raman spectrometer to obtain the surface-enhanced Raman spectra of the plurality of mixed solutions E with different concentrations; S404: calculating the Raman characteristic peak intensity of the surface-enhanced Raman spectra of the plurality of mixed solutions E with different concentrations according to the surface-enhanced Raman spectra of the plurality of mixed solutions E with different concentrations, and determining the relationship curve between the Raman characteristic peak intensity and the concentration of sodium chloride.

3. The method of claim 2, wherein the method is a portable Raman spectroscopy-based method for quantitatively detecting chloride in cerebrospinal fluid. Step S5 comprises: S501: mixing the mixed solution D with the to-be-tested cerebrospinal fluid sample according to a volume ratio of 1:1-4 to obtain a mixed solution F; S502: dropping the mixed solution F on the titanium dioxide super-hydrophobic support substrate, and detecting the droplets of the mixed solution F on the titanium dioxide super-hydrophobic support substrate using a portable Raman spectrometer to obtain the surface-enhanced Raman spectrum of the mixed solution F; S503: determining the Raman characteristic peak intensity of the surface-enhanced Raman spectrum of the mixed solution F according to the surface-enhanced Raman spectrum of the mixed solution F; S504: determining the concentration of sodium chloride in the to-be-tested cerebrospinal fluid sample according to the Raman characteristic peak intensity of the surface-enhanced Raman spectrum of the mixed solution F and the relationship curve.

4. The method for quantitatively detecting chloride in cerebrospinal fluid based on portable Raman spectroscopy according to claim 1, characterized in that, Step S1 comprises: The silver nitrate aqueous solution, the deionized water and the sodium citrate aqueous solution are mixed in a container, stirred and heated to boiling, then the sodium citrate aqueous solution is added and stirred, the heating is stopped after the reaction is completed, the stirring is stopped after the solution is cooled to room temperature, and a silver nanocolloid solution A is obtained; the volume ratio of the silver nitrate aqueous solution, the deionized water and the sodium citrate aqueous solution is 1:9:0.1-1.

5. The method for quantitative detection of chloride in cerebrospinal fluid based on portable Raman spectroscopy according to claim 1, characterized in that, The diameter of the silver nanoparticles in the silver nanocolloid solution A is 30-100 nm.

6. The method for quantitative detection of chloride in cerebrospinal fluid based on portable Raman spectroscopy according to claim 1, characterized in that, The step S2 comprises: S201: 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane is added to anhydrous ethanol to prepare a mixed solution B; S202: two kinds of titanium dioxide nanoparticles with different sizes are mixed in a mass ratio of 1:1 and then added to the mixed solution B to prepare a titanium dioxide super-hydrophobic reagent C; S203: the titanium dioxide super-hydrophobic reagent C is coated on a substrate and dried to obtain a titanium dioxide super-hydrophobic support substrate.

7. The method according to claim 6, wherein, The volume ratio of 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane to anhydrous ethanol in the mixed solution B is 1:50-200.

8. The method of claim 6, wherein the method is a portable Raman spectroscopy-based method for quantitatively detecting chloride in cerebrospinal fluid. The diameter of the titanium dioxide nanoparticles is 10-150 nm.

9. The method of claim 1, wherein the method is a portable Raman spectroscopy-based method for quantitatively detecting chloride in cerebrospinal fluid. The step S3 comprises: S301: the silver nanocolloid solution A is centrifuged and concentrated by 5-20 times to obtain a concentrated silver nanocolloid solution; S302: the concentrated silver nanocolloid solution and a potassium iodide aqueous solution are mixed, and a mixed solution D is obtained after standing at room temperature.

10. The method of claim 1, wherein the method is a portable Raman spectroscopy-based method for quantitatively detecting chloride in cerebrospinal fluid. In the steps S4 and S5, the detection conditions of the surface-enhanced Raman spectrum are as follows: the laser wavelength is 785 nm, the power is 10%-50% of the maximum power of a portable Raman spectrometer, and the integration time is 1-3 s.

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