Solid surface enhanced Raman scattering substrate and preparation method and application thereof

Abstract

The invention discloses a solid-state surface-enhanced Raman scattering substrate and a preparation method and application thereof, the solid-state surface-enhanced Raman scattering substrate comprises a cotton substrate, nano-silver particles and a zeolite imidazate framework material are sequentially loaded on the cotton substrate, and the zeolite imidazate framework material wraps nano-silver ions. According to the solid-state SERS substrate disclosed by the invention, under the synergistic effect of the nano-silver particles and the zeolite imidazate framework material, a relatively strong surface-enhanced Raman scattering effect can be generated, and the solid-state SERS substrate has relatively high sensitivity and relatively good repeatability and reproducibility when free sulfydryl is detected. In addition, the zeolite imidazate framework material on the SERS substrate wraps nano-silver ions, oxidation of silver nanoparticles can be avoided, and the stability of the SERS substrate is improved. The solid SERS substrate can be used for preparing a glucose recognition probe and a lactic acid recognition probe, and has the characteristics of high anti-interference capability, good reproducibility and the like in detection of glucose / lactic acid in human sweat.

Description

Technical Field

[0001] The invention belongs to the technical field of biological detection materials, and in particular relates to a solid surface enhanced Raman scattering substrate and a preparation method and application thereof. Background Art

[0002] Among common human biological fluids, human sweat shows unique advantages in non-invasive collection and is an ideal substitute for traditional blood samples. Glucose and lactate are two important biomarkers in sweat that are closely related to energy metabolism status and human health. The level of glucose in human sweat can provide sufficient information for diabetes diagnosis and athletic performance, but it is easily affected by factors such as daily diet and exercise. In addition, the lactate level in human sweat is closely related to the body's energy metabolism, so it is an important biomarker for evaluating stress-induced ischemia and physical fatigue. Therefore, a fast, accurate, stable and sensitive method for quantitative analysis of glucose and lactate in sweat was established.

[0003] At present, the detection methods of glucose and lactic acid in sweat at home and abroad are mainly electrochemical method, spectrophotometry and ion chromatography. The above methods have many inconveniences such as complex sample pretreatment process, time-consuming and insufficient accuracy, and thus cannot meet the needs of on-site rapid detection. Summary of the invention

[0004] In order to overcome the problems existing in the above-mentioned prior art, one of the objects of the present invention is to provide a solid surface enhanced Raman scattering substrate. The second object of the present invention is to provide a method for preparing the above-mentioned solid surface enhanced Raman scattering substrate. The third object of the present invention is to provide the application of the above-mentioned solid surface enhanced Raman scattering substrate. The fourth object of the present invention is to provide an identification probe. The fifth object of the invention is to provide the application of the above-mentioned identification probe. The sixth object of the present invention is to provide an identification probe. The seventh object of the invention is to provide the application of the above-mentioned identification probe.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] The first aspect of the present invention provides a solid-state surface enhanced Raman scattering substrate, comprising a substrate on which nano silver ions wrapped by a zeolite imidazolate framework material are loaded.

[0007] Preferably, the substrate is a cotton substrate.

[0008] More preferably, the solid-state surface enhanced Raman scattering substrate is composed of a sampling cotton swab, nano silver ions, and a zeolite imidazolate framework material; the head of the sampling cotton swab is loaded with nano silver ions wrapped in the zeolite imidazolate framework material.

[0009] The solid surface enhanced Raman scattering (SERS) substrate of the present invention uses a sampling cotton swab as a carrier to prepare a portable solid SERS substrate, which is low-cost, easy to carry, and suitable for integrated collection and detection of glucose and lactic acid in liquid samples such as sweat.

[0010] The second aspect of the present invention provides a method for preparing the solid-state surface enhanced Raman scattering substrate according to the first aspect, characterized in that it comprises the following steps:

[0011] S1, reacting the substrate with the silver ion solution attached thereto with a reducing agent to obtain a substrate loaded with nanosilver particles;

[0012] S2. The substrate loaded with nano-silver particles is reacted in a mixed solution containing 2-methylimidazole and a zinc source to obtain a substrate loaded with nano-silver ions wrapped with a zeolite imidazolate framework material, i.e., a solid-state surface enhanced Raman scattering substrate.

[0013] Preferably, the step S1 specifically comprises the following steps: immersing the substrate in a silver ion solution to attach silver ions, and immersing the substrate attached with the silver ion solution in a reducing agent solution for reaction.

[0014] More preferably, the silver ion solution is selected from silver ammonia solution or silver nitrate solution.

[0015] More preferably, the concentration of the silver ion solution is 40-60 mmol / L.

[0016] More preferably, the concentration of the reducing agent solution is 50-100 mmol / L.

[0017] More preferably, the step S1 further comprises the following step: reattaching the silver particles to the substrate loaded with nano-silver particles and immersing the substrate in a reducing agent solution for reaction, and the reaction is cycled for 3-10 times.

[0018] Further preferably, the step S1 further comprises the following step: reattaching the sampling cotton swab loaded with nano-silver particles to the silver particles and immersing the same in a reducing agent solution for reaction, and the reaction is cycled for 3-10 times.

[0019] More preferably, the reaction in step S1 is carried out under shaking conditions.

[0020] More preferably, the immersion time in the silver ion solution in step S1 is 2-5 minutes.

[0021] More preferably, the time of immersing in the reducing agent solution in step S1 is 2-5 minutes.

[0022] Preferably, the step S1 further comprises the following steps: washing the substrate loaded with the nanosilver particles with anhydrous ethanol, and then drying with nitrogen.

[0023] Preferably, the reducing agent is selected from at least one of formaldehyde, acetaldehyde, glucose, potassium sodium tartrate and ascorbic acid.

[0024] Preferably, the reaction time of the reaction in step S2 is 3-10 min, and the reaction temperature is 15-40°C.

[0025] Preferably, in the mixed solution containing 2-methylimidazole and a zinc source, the concentration of the zinc source is 10-100 mmol / L, the concentration of the 2-methylimidazole is 20-300 mmol / L, and the molar ratio of the zinc source to 2-methylimidazole is 1:(2-3).

[0026] Preferably, the zinc source is zinc nitrate.

[0027] Preferably, the solvent of the mixed solution containing 2-methylimidazole and the zinc source is an alcohol solvent.

[0028] Preferably, the step S2 further comprises the following steps: washing the substrate sequentially loaded with the nano-silver particles and the zeolite imidazolate framework material with anhydrous ethanol, and then drying with nitrogen.

[0029] The third aspect of the present invention provides the use of the solid-state surface enhanced Raman scattering substrate described in the first aspect in detecting free thiol groups.

[0030] Preferably, the solid-state surface enhanced Raman scattering substrate is used to detect 4-mercaptophenylboronic acid or 5,5'-dithiobis(2-nitrobenzoic acid).

[0031] The fourth aspect of the present invention provides an identification probe, comprising the solid-state surface enhanced Raman scattering substrate described in the first aspect, wherein the surface of the solid-state surface enhanced Raman scattering substrate is modified with 4-mercaptophenylboronic acid.

[0032] Preferably, the recognition probe is prepared by a preparation method comprising the following steps: immersing a solid-state surface enhanced Raman scatterer in a 4-mercaptophenylboric acid solution and allowing it to stand for modification to obtain the recognition probe.

[0033] More preferably, the concentration of the 4-mercaptophenylboronic acid solution is 10-50 μmol / L.

[0034] More preferably, the standing time is 0.5-3h.

[0035] The fifth aspect of the present invention provides use of the recognition probe described in the fourth aspect in detecting glucose or preparing a glucose sensor.

[0036] Preferably, the use of the recognition probe in detecting glucose in sweat

[0037] Preferably, the method for detecting glucose comprises the following steps:

[0038] Prepare glucose standard solutions of different concentrations, and use the recognition probe described in the fourth aspect for detection, and draw a standard curve based on the peak values ​​of the characteristic Raman shift of glucose of different concentrations and the concentration of the glucose standard solution; use the above-mentioned recognition probe to collect and detect the liquid to be tested, and compare the peak value of the characteristic Raman shift obtained with the standard curve to obtain the concentration of glucose in the liquid to be tested.

[0039] More preferably, the liquid to be tested is human sweat.

[0040] The sixth aspect of the present invention provides an identification probe, comprising the solid-state surface-enhanced Raman scattering substrate described in the first aspect, wherein the surface of the solid-state surface-enhanced Raman scattering substrate is modified with 5,5'-dithiobis(2-nitrobenzoic acid).

[0041] Preferably, the recognition probe is prepared by a preparation method comprising the following steps: immersing a solid-state surface enhanced Raman scattering in a 5,5'-dithiobis(2-nitrobenzoic acid) solution and allowing it to stand for modification to obtain the recognition probe.

[0042] More preferably, the concentration of the 5,5'-dithiobis(2-nitrobenzoic acid) solution is 10-50 μmol / L.

[0043] More preferably, the standing time is 0.5-3h.

[0044] The seventh aspect of the present invention provides use of the recognition probe described in the sixth aspect in detecting lactic acid or preparing a lactic acid sensor.

[0045] Preferably, the use of the recognition probe in detecting lactic acid in sweat

[0046] Preferably, the method for detecting lactic acid comprises the following steps:

[0047] Prepare lactic acid standard solutions of different concentrations, and use the recognition probe described in the sixth aspect for detection, and draw a standard curve based on the peak values ​​of the characteristic Raman shift of lactic acid of different concentrations and the concentration of the lactic acid standard solution; use the above-mentioned recognition probe to collect and detect the liquid to be tested, and compare the peak value of the characteristic Raman shift obtained with the standard curve to obtain the concentration of lactic acid in the liquid to be tested.

[0048] More preferably, the liquid to be tested is human sweat.

[0049] The beneficial effects of the present invention are:

[0050] The invention provides a solid surface enhanced Raman scattering (SERS) substrate. The composite material can produce a strong surface enhanced Raman scattering effect by synergistically acting with nano silver particles and zeolite imidazolate skeleton material (ZIF8). It has high sensitivity and good repeatability and reproducibility when detecting free thiol groups. When the concentration of 4-mercaptophenylboronic acid is reduced to 1.0 ng / L and the concentration of 5,5'-dithiobis(2-nitrobenzoic acid) is reduced to 10.0 ng / L, there is still a SERS signal, indicating that the portable solid SERS substrate of the invention can produce a strong SERS effect and has high sensitivity. In addition, the zeolite imidazolate skeleton material on the SERS substrate of the invention wraps nano silver ions, which can avoid oxidation of silver nano particles and improve the stability of the SERS substrate.

[0051] Specifically, compared with the prior art, the present invention also has the following advantages:

[0052] (1) The preparation method of the solid surface enhanced Raman scattering substrate of the present invention is simple, rapid, low-cost and easy to store. It can be further made into a cotton swab as a solid substrate to improve the portability of the product and realize the integration of sample collection and detection.

[0053] (2) The solid-state SERS substrate of the present invention can be used to prepare glucose recognition probes. Due to the high selectivity of 4-mercaptophenylboronic acid, the solid-state surface enhanced Raman scattering substrate has specific selectivity and high sensitivity to glucose within a certain range, and the detection limit can be as low as 0.04 μmol / L. It has the characteristics of high anti-interference ability and good reproducibility in the detection of glucose in human sweat.

[0054] (3) The solid-state SERS substrate of the present invention can be used to prepare lactic acid recognition probes. Due to the high selectivity of 5,5'-dithiobis(2-nitrobenzoic acid), the solid-state surface enhanced Raman scattering substrate has specific selectivity and high sensitivity to lactic acid within a certain range, and the detection limit can be as low as 0.03 mmol / L. It has the characteristics of high anti-interference ability and good reproducibility in the detection of lactic acid in human sweat. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is a scanning electron microscope photograph of the portable solid-state surface-enhanced Raman scattering substrate of Example 1;

[0056] Figure 2 The XPS peak separation results of Ag 3d, C 1s, N 1s, and Zn 2p of the portable solid-state surface enhanced Raman scattering substrate of Example 1;

[0057] Figure 3The SERS signal responses of the cotton swab (curve a), the substrate of comparative example 1 (curve b), the substrate of comparative example 2 (curve c) and the portable solid-state SERS substrate of Example 1 (curve d) to 4-mercaptophenylboronic acid are shown;

[0058] Figure 4 The SERS signal response diagrams of the cotton swab (curve a), the substrate of comparative example 1 (curve b), the substrate of comparative example 2 (curve c) and the portable solid-state SERS substrate of Example 1 (curve d) to 5,5'-dithiobis(2-nitrobenzoic acid);

[0059] Figure 5 The SERS spectra of the portable solid-state SERS substrate of Example 1 to different concentrations of 4-mercaptophenylboric acid;

[0060] Figure 6 The SERS spectra of the portable solid-state SERS substrate of Example 1 to different concentrations of 5,5'-dithiobis(2-nitrobenzoic acid);

[0061] Figure 7 a is the response diagram of the portable solid-state SERS substrate of Example 1 to 11 consecutive SERS tests of 4-mercaptophenylboronic acid, Figure 7 b is the random 11-point SERS test response diagram, Figure 7 c is the SERS test response diagram of 17 batches of portable solid-state surface enhanced Raman scattering substrates, Figure 7 d is the SERS test response graph of the portable solid-state surface enhanced Raman scattering substrate within 9 weeks;

[0062] Figure 8 a is the response diagram of the portable solid-state SERS substrate of Example 1 to 11 consecutive SERS tests of 5,5'-dithiobis(2-nitrobenzoic acid), Figure 8 b is the random 11-point SERS test response diagram, Figure 8 c is the SERS test response diagram of 17 batches of portable solid-state surface enhanced Raman scattering substrates, Figure 8 d is the SERS test response graph of the portable solid-state surface enhanced Raman scattering substrate within 9 weeks;

[0063] Fig. 9 This is the SERS response diagram for glucose analysis;

[0064] Fig.10 The concentration of glucose at 1069 cm -1 Standard curve of peak value and response concentration;

[0065] Fig.11 SERS spectrum of glucose test in the sweat of volunteers;

[0066] Fig.12a is the SERS response bar graph of different glucose analogs and glucose. Fig.12 b is the SERS response diagram of different glucose analogs coexisting with glucose;

[0067] Fig.13 This is the SERS response diagram for lactic acid analysis;

[0068] Fig.14 The concentration of lactic acid at 1330 cm -1 Standard curve of peak value and response concentration;

[0069] Fig.15 This is the SERS spectrum of lactic acid test in the sweat of volunteers. DETAILED DESCRIPTION

[0070] The present invention is further described in detail below through specific examples. The raw materials used in the following examples, unless otherwise specified, can be obtained from conventional commercial sources or prepared and separated by simple synthesis; the processes used, unless otherwise specified, are conventional processes in the art.

[0071] Example 1

[0072] This embodiment provides a portable solid-state surface-enhanced Raman scattering substrate, and the preparation process is as follows:

[0073] (1) Preparation of a cotton swab modified with nanosilver particles: soaking the cotton swab in a 50 mmol / L silver ammonia solution, shaking and reacting at 150 rpm / min for 2.5 min, then soaking the cotton swab in a 78 mmol / L glucose solution, shaking and reacting at 150 rpm / min for 2.5 min, repeating the reaction for 5 times, washing with anhydrous ethanol for 3 times, and drying with nitrogen to obtain a cotton swab modified with nanosilver particles;

[0074] (2) Preparation of a portable solid-state surface-enhanced Raman scattering substrate: Take the cotton swab modified with the nanosilver particles prepared in step (1), immerse it in a mixed solution of 1 mL 125 mmol / L zinc nitrate and 1 mL 250 mmol / L 2-methylimidazole methanol, let it react at 30° C. for 5 min, wash it with anhydrous ethanol three times, and dry it with nitrogen to obtain a portable solid-state surface-enhanced Raman scattering substrate.

[0075] Figure 1 This is a scanning electron microscope image of the prepared portable solid-state surface-enhanced Raman scattering substrate. Figure 1 It can be seen that ZIF-8 is wrapped on the cotton swab modified with nanosilver particles; Figure 2The XPS peak analysis results of Ag 3d, C 1s, N 1s, and Zn 2p of the portable solid-state surface enhanced Raman scattering substrate prepared in Example 1 are as follows: Figure 2 It can be seen that the portable solid-state surface enhanced Raman scattering substrate of the present invention has been successfully prepared.

[0076] Comparative Example 1

[0077] This comparative example prepares a substrate, which is different from Example 1 in that ZIF-8 is not added. The specific process is the cotton swab modified with nanosilver particles prepared in step (1) of Example 1.

[0078] Comparative Example 2

[0079] This comparative example prepares a substrate, which differs from Example 1 in that no nanosilver particles are added. The specific process is as follows:

[0080] The cotton swab was immersed in a mixed solution of 1 mL 125 mmol / L zinc nitrate and 1 mL 250 mmol / L 2-methylimidazole methanol, allowed to react at 30°C for 5 min, washed three times with anhydrous ethanol, and dried with nitrogen to obtain a ZIF8-modified cotton swab.

[0081] Performance Testing

[0082] The performance of the substrates prepared in Example 1 and Comparative Examples 1-2 was tested, and the specific test contents are as follows:

[0083] 1. The specific test method is as follows: the cotton swabs prepared in Example 1 and Comparative Examples 1-2 and the blank control are respectively immersed in 4-mercaptophenylboric acid and 5,5'-dithiobis(2-nitrobenzoic acid) solutions, and then the SERS response intensity is directly detected by a portable i-RamanPlus Raman instrument, the excitation intensity is 110 mV, the integration time is 10 s, each concentration is tested three times continuously, and these three data are used for statistics, and the intensity at 1069 cm -1 and 1330cm -1 The SERS response is investigated by measuring the peak intensity of the characteristic peak.

[0084] 2. Test results

[0085] Specific test results are as follows Figure 3 and Figure 4 As shown, in Figure 3 In the figure, curve a is a blank cotton swab, curve b and curve c are signal response diagrams of the substrates in comparative examples 1 to 2 for detecting 4-mercaptophenylboronic acid, respectively; curve d is the SERS signal response diagram of the portable solid-state SERS substrate of Example 1 for detecting 4-mercaptophenylboronic acid; in Figure 4In the figure, curve a is a cotton swab, curves b to c are the signal response diagrams of the substrates in comparative examples 1 to 2 to detect 5,5'-dithiobis(2-nitrobenzoic acid), respectively; curve d is the SERS signal response diagram of the portable solid-state SERS substrate of Example 1 to detect 5,5'-dithiobis(2-nitrobenzoic acid). Figure 3 and Figure 4 It can be clearly seen that the SERS signal response effect when using the portable solid-state SERS substrate of the present invention to detect 4-mercaptophenylboric acid and 5,5'-dithiobis(2-nitrobenzoic acid) is the best, and the synergistic effect of the nanosilver particles and the zeolite imidazolate framework material (ZIF8) can produce a strong surface enhanced Raman scattering effect, while the comparative example 1 with only nanosilver particles produces a weak Raman scattering effect, and the comparative example 2 with only ZIF8 does not produce a Raman scattering effect.

[0086] The portable solid-state SERS substrate prepared in Example 1 was used to perform SERS detection on 4-mercaptophenylboric acid and 5,5'-dithiobis(2-nitrobenzoic acid). The specific process was as follows: the portable solid-state SERS substrate prepared in Example 1 was immersed in 1 mL of 4-mercaptophenylboric acid solution with different concentrations (specific concentrations were 1.0 ng / L, 10.0 ng / L, 100.0 ng / L, 1.0 μg / L, 10.0 μg / L, 100.0 μg / L, and 1.0 mg / L), and then SERS detection was performed. The specific test results are shown in FIG. Figure 5 As shown, Figure 5 The curves in the figure are SERS test curves of 1.0 ng / L, 10.0 ng / L, 100.0 ng / L, 1.0 μg / L, 10.0 μg / L, 100.0 μg / L, and 1.0 mg / L respectively from bottom to top; the portable solid-state SERS substrate prepared in Example 1 is immersed in 1 mL of 5,5'-dithiobis(2-nitrobenzoic acid) solution of different concentrations (specific concentrations are 10.0 ng / L, 100.0 ng / L, 1.0 μg / L, 10.0 μg / L, and 0.1 mg / L), and then SERS detection is performed. The specific test results are shown in FIG. Figure 6 As shown, Figure 6 The curves in the figure are the SERS test curves of 10.0 ng / L, 100.0 ng / L, 1.0 μg / L, 10.0 μg / L, and 0.1 mg / L from bottom to top. Figure 5 and Figure 6It can be seen that when the portable solid-state SERS substrate in Example 1 is used to perform SERS detection on different concentrations of 4-mercaptophenylboric acid and 5,5'-dithiobis(2-nitrobenzoic acid), when the concentration of 4-mercaptophenylboric acid drops to 1.0 ng / L and the concentration of 5,5'-dithiobis(2-nitrobenzoic acid) drops to 10.0 ng / L, there is still a SERS signal, indicating that the portable solid-state SERS substrate in the present invention can produce a strong SERS effect and has a higher sensitivity.

[0087] The repeatability and reproducibility of the portable solid-state SERS substrate in Example 1 were tested. The specific test results are as follows: Figure 7 and Figure 8 As shown, Figure 7 a and Figure 8 a is a SERS test response diagram of the portable solid-state SERS substrate in Example 1 for 11 consecutive tests on 4-mercaptophenylboronic acid and 5,5'-dithiobis(2-nitrobenzoic acid) molecules, with relative standard deviations of 1.7% and 1.2%, respectively; Figure 7 b and Figure 8 b is a SERS test response diagram of 11 random points on the portable solid-state SERS substrate in Example 1, with relative standard deviations of 4.0% and 1.9% respectively; Figure 7 c and Figure 8 c is a SERS test response diagram of 17 batches of the portable solid-state SERS substrate in Example 1, with relative standard deviations of 3.5% and 2.0% respectively; Figure 7 d and Figure 8 d is the SERS test response diagram of the portable solid-state SERS substrate in Example 1 within 9 weeks, and the relative standard deviations are 3.3% and 2.1% respectively. Figure 7 and Figure 8 It can be seen that the portable solid-state SERS substrate test of the present invention has good repeatability and reproducibility for 4-mercaptophenylboronic acid and 5,5'-dithiobis(2-nitrobenzoic acid).

[0088] Example 2

[0089] Example 2 provides a glucose recognition probe, a preparation method thereof, and a method for quantitatively analyzing glucose in sweat, the specific steps of which are:

[0090] (1) Preparation of glucose recognition probe

[0091] The portable solid-state surface enhanced Raman scattering substrate of Example 1 was soaked in 1 mL of 20 μmol / L 4-mercaptophenylboric acid solution, allowed to stand for 1 h, washed with anhydrous ethanol 3 times, and dried with nitrogen to obtain a glucose recognition probe.

[0092] (2) Drawing of glucose standard curve:

[0093] Prepare glucose standard solutions with concentrations of 0.1μmol / L, 0.5μmol / L, 5μmol / L, 10μmol / L, 20μmol / L, 50μmol / L, and 100μmol / L, respectively. Immerse the glucose recognition probe in 1mL of glucose standard solution and incubate for 10 minutes. Use a portable i-Raman Plus Raman instrument for direct detection with an excitation intensity of 110mV and an integration time of 10s. Detect each concentration of solution three times in succession, take the average value and relative deviation, and plot the 1069cm -1 Raman shift peak-glucose concentration standard curve, see Fig. 9 and Fig.10 The detection limit was 0.04 μmol / L (S / N=3), with the lowest concentration that could detect a signal with a 3-fold signal-to-noise ratio. The linear range and detection limit of this method could meet the needs of actual sample analysis.

[0094] (3) Detection of glucose in sweat

[0095] The sweat samples of three volunteers were collected using a glucose recognition probe and then incubated for 10 minutes before SERS detection. The SERS signals were as follows: Fig.11 As shown, the test was repeated three times and the 1069cm of the three data points was calculated. -1 Substituting the peak value average value and relative standard deviation into the standard curve, it was shown that the glucose concentrations in the sweat of the three volunteers were 38.4 (± 0.15) μmol / L, 46.7 (± 0.89) μmol / L, and 32.9 (± 0.72) μmol / L, respectively. The relative deviation of the test results was 0.4% to 2.2%.

[0096] The accuracy of the quantitative analysis method of glucose in sweat in Example 2 was verified by a commercial glucose meter. Glucose in the sweat of three volunteers was detected according to the operating instructions of the glucose meter. After detection by the glucose meter, the glucose concentrations in the sweat of the three volunteers were 41.0 μmol / L, 45.0 μmol / L, and 32.0 μmol / L, respectively. The relative deviation from the detection result of the above-mentioned SERS analysis method was between -6.4% and 3.8%, which proved the reliability of the quantitative analysis method of glucose in sweat.

[0097] In order to verify that the quantitative analysis method for glucose in sweat has specific selection and anti-interference for glucose, the method of the present invention is used to detect substances with similar structures to glucose: ascorbic acid, dopamine, glycine, urea, citric acid, uric acid, and lactic acid. The SERS spectra are shown in the following figure. Fig.12 As shown in a. Fig.12It can be seen that when the glucose quantitative analysis method of the present invention is used to detect the above eight substances, the SERS responses of ascorbic acid, dopamine, glycine, urea, citric acid, uric acid, and lactic acid are all weak. In addition, Fig.12 b is the SERS response diagram of the above series of glucose structural analogs coexisting with glucose. Fig.12 b It can be seen that when glucose and the above-mentioned interferents exist at the same time, the SERS response hardly changes, which shows that the method of the present invention can accurately determine the content of glucose.

[0098] Example 3

[0099] Example 3 provides a lactic acid recognition probe, a preparation method thereof, and a quantitative analysis method of lactic acid in sweat, the specific steps are as follows:

[0100] (1) Preparation of lactate recognition probe

[0101] The portable solid-state surface enhanced Raman scattering substrate of Example 1 was soaked in 1 mL of 20 μmol / L 5,5'-dithiobis(2-nitrobenzoic acid) solution, allowed to stand for 1 h, washed with anhydrous ethanol three times, and dried with nitrogen to obtain a lactic acid recognition probe.

[0102] (2) Drawing of lactic acid standard curve:

[0103] Prepare the lactic acid standard solutions with concentrations of 0.1mmol / L, 0.5mmol / L, 1mmol / L, 2mmol / L, 5mmol / L, 10mmol / L, 20mmol / L, and 50mmol / L respectively. Immerse the lactic acid recognition probe in 1mL of lactic acid standard solution and incubate for 10 minutes. Use the portable i-Raman Plus Raman instrument for direct detection, with an excitation intensity of 110mV and an integration time of 10s. Detect the solution of each concentration three times in succession, take the average value and relative deviation, and plot the 1330cm -1 The standard curve of Raman shift peak value and lactic acid concentration is shown in Fig.13 and Fig.14 The detection limit was 0.03mmol / L (S / N=3), which was the lowest concentration that could detect a signal with a 3-fold signal-to-noise ratio. The linear range and detection limit of this method could meet the needs of actual sample analysis.

[0104] (3) Detection of lactic acid in sweat

[0105] The lactic acid recognition probe was used to collect sweat from the surface of three volunteers, and then incubated for 10 minutes before SERS detection. The measured SERS signal is as follows: Fig.15 As shown, the test was repeated three times and the 1330cm of the three data points was calculated. -1Substituting the peak value average and relative standard deviation into the standard curve, it was shown that the lactic acid concentrations in the sweat of the three volunteers were 9.3 (± 0.03) mmol / L, 9.1 (± 0.09) mmol / L, and 12.1 (± 0.29) mmol / L, respectively. The relative deviation of the test results was 0.3% to 2.4%.

[0106] The accuracy of the quantitative analysis method of lactic acid in sweat in Example 2 was verified by a commercial lactate meter. The lactic acid in the sweat of three volunteers was detected according to the operating instructions of the lactate meter. The lactic acid concentrations in the sweat of the three volunteers were 9.6mmol / L, 9.0mmol / L, and 11.4mmol / L, respectively, which were relatively different from the detection results of the above-mentioned SERS analysis method, and the reliability of the quantitative analysis method of lactic acid in sweat was verified.

[0107] In order to verify that the quantitative analysis method of lactic acid in sweat has specific selection and anti-interference for lactic acid, the method of the present invention is used to detect substances with similar structures to lactic acid: ascorbic acid, dopamine, glycine, urea, citric acid, uric acid, and glucose. The quantitative analysis method of lactic acid of the present invention is used to detect the above eight substances. The SERS responses of ascorbic acid, dopamine, glycine, urea, citric acid, uric acid, and glucose are all weak. In addition, when lactic acid and the above interfering substances exist at the same time, the SERS response is almost unchanged, which shows that the method of the present invention can accurately determine the content of lactic acid.

[0108] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A solid surface enhanced Raman scattering substrate, characterized in that: The invention comprises a substrate, on which nano silver ions wrapped by zeolite imidazolate framework materials are loaded.

2. The solid-state surface enhanced Raman scattering substrate according to claim 1, characterized in that: The substrate is a cotton substrate.

3. The method for preparing a solid-state surface enhanced Raman scattering substrate according to claim 1 or 2, characterized in that: The steps include: S1, reacting the substrate with the silver ion solution attached thereto with a reducing agent to obtain a substrate loaded with nanosilver particles; S2. The substrate loaded with nano-silver particles is reacted in a mixed solution containing 2-methylimidazole and a zinc source to obtain a substrate loaded with nano-silver ions wrapped with a zeolite imidazolate framework material, i.e., a solid-state surface enhanced Raman scattering substrate.

4. The method for preparing a solid-state surface enhanced Raman scattering substrate according to claim 3, characterized in that: The step S1 specifically comprises the following steps: immersing the substrate in a silver ion solution to attach silver ions, and immersing the cotton substrate attached with the silver ion solution in a reducing agent solution to react; And / or, the reducing agent is selected from at least one of formaldehyde, acetaldehyde, glucose, potassium sodium tartrate, and ascorbic acid.

5. The method for preparing a solid-state surface enhanced Raman scattering substrate according to claim 3, characterized in that: The reaction time of the reaction in step S2 is 3-10 min, and the reaction temperature is 15-40°C.

6. Use of the solid-state surface enhanced Raman scattering substrate according to any one of claims 1 to 2 in detecting free thiol groups.

7. A recognition probe, characterized in that The invention comprises the solid-state surface enhanced Raman scattering substrate according to any one of claims 1 to 2, wherein the surface of the solid-state surface enhanced Raman scattering substrate is modified with 4-mercaptophenylboronic acid.

8. Use of the recognition probe according to claim 7 in detecting glucose or preparing a glucose sensor.

9. A recognition probe, characterized in that The invention comprises the solid-state surface enhanced Raman scattering substrate according to any one of claims 1 to 2, wherein the surface of the solid-state surface enhanced Raman scattering substrate is modified with 5,5'-dithiobis(2-nitrobenzoic acid).

10. Use of the recognition probe according to claim 9 in detecting lactic acid or preparing a lactic acid sensor.

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