SERS detection method for organophosphorus compounds DMMP, DECMP and malathion

Abstract

The invention discloses an SERS detection method for organophosphorus compounds DMMP, DECMP and malathion, and relates to the field of surface enhanced Raman spectrum detection. The method comprises the following specific steps: preparing a metal 1 monatomic precursor solution; dropwise adding a metal 2 compound into the metal 1 monatomic precursor solution, uniformly stirring, diluting, adjusting the pH value, and putting a beaker containing the mixed solution into UV photocuring equipment for illumination, so as to synthesize metal 2 nano-particle sol; centrifugally cleaning with an acid solvent or an organic solvent, and concentrating; immersing a silicon wafer into the nanoparticle sol, continuously illuminating for several minutes, standing for a period of time, illuminating again, and repeating the steps to prepare the SERS substrate; a to-be-detected object is taken and dropwise added to the SERS substrate, and a Raman spectrometer is used for detection. The hot spot density and the hot spot utilization rate of the multilayer SERS substrate are improved, and SERS quantitative detection of dimethyl methylphosphate, diethyl chloromethylphosphate and malathion is realized.

Description

Technical Field

[0001] The invention relates to the technical field of surface enhanced Raman spectroscopy (SERS) detection, in particular to a SERS detection method for organophosphorus compounds DMMP, DECMP and malathion. Background Art

[0002] The chemical structure of organophosphorus compounds is a phosphorus-containing organic compound (CP bond, CNP bond, or COP bond, etc.), which belongs to organophosphorus or organophosphate compounds. Organophosphorus compounds are stable under acidic and neutral conditions, and are easily hydrolyzed and ineffective under alkaline conditions. If organophosphorus compounds exist in the environment, they can enter the human body through ingestion, breathing, skin, etc., which can inhibit the activity of acetylcholinesterase, leading to acetylcholine metabolic disorders and large accumulation in the nervous system, and have toxic nicotinic effects, nicotinic effects and central nervous system effects on cholinergic nerves, thereby causing a series of neurotoxic symptoms such as spasms, diarrhea, vomiting, convulsions, paralysis, and even death. Therefore, there is an urgent need for on-site rapid, trace sensitive, and portable detection methods.

[0003] At present, the main methods for detecting organophosphorus compounds are gas chromatography, high performance liquid chromatography, gas chromatography-mass spectrometry, and high performance liquid chromatography-mass spectrometry. However, surface-enhanced Raman scattering (SERS) technology is a new type of organophosphorus compound detection technology. The difference between this detection technology and other detection technologies is that it mainly uses Raman scattering to detect organophosphorus compounds.

[0004] SERS is not only a simple, fast, non-destructive (non-invasive), high-resolution (narrower fingerprint peak) detection technology capable of analyzing molecular content and types, but also capable of analyzing the structural details, chemical groups, and molecular orientation of substances. Therefore, SERS technology has a wide range of applications in the fields of pharmaceutical industry detection, toxic or explosive dangerous goods detection, in vitro physiological index detection, in situ reaction monitoring, etc. The detection method of organophosphorus compounds based on SERS technology has the advantages of rapidity, specificity, and high sensitivity, and is suitable for military, public safety, environmental monitoring and other fields. Summary of the invention

[0005] In view of this, the main purpose of the present invention is to provide a SERS detection method for organophosphorus compounds DMMP, DECMP and malathion, utilizing the high hotspot density and hotspot utilization rate of the multilayer SERS substrate to achieve SERS highly sensitive detection of organophosphorus compounds DMMP, DECMP and malathion.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The invention discloses a SERS detection method for organophosphorus compounds DMMP, DECMP and malathion, comprising the following steps:

[0008] S1, preparing a metal 1 single atom precursor solution, wherein the metal 1 single atom precursor solution contains an alcohol compound having reducing properties with metal 1;

[0009] S2, adding the metal 2 compound solution dropwise to the metal 1 single atom precursor solution obtained in step S1 and diluting after stirring at a certain speed, using an organic solvent as the diluent, and adjusting the pH to be acidic, placing a transparent container such as a beaker containing the mixed solution in a UV light curing device for several minutes, and photochemically synthesizing a sol containing metal 2 nanoparticles of different particle sizes;

[0010] S3, washing the metal 2 nanometer particle sol obtained in step S2 by centrifugation with an acidic solvent or an organic solvent, and concentrating the metal 2 nanometer particle sol after centrifugation washing.

[0011] S4, immersing the silicon wafer in the metal 2 nanoparticle sol obtained in step S3, irradiating for several minutes, then stopping the irradiation and letting it stand for a period of time, irradiating for several minutes again, then stopping the irradiation and letting it stand for a period of time, repeating the irradiation-stopping the irradiation and letting it stand for a period of time, and thus preparing a gold nanoparticle multilayer surface enhanced Raman spectroscopy (SERS) substrate;

[0012] S5. After the taken-out SERS substrate is dried, the solution of the substance to be tested is dripped onto the silicon wafer and detected by Raman spectroscopy.

[0013] As a further scheme of the present invention: in step S1, the metal 1 single atom precursor solution is one or more of a metal 1 single atom solution, a metal 1 oxide cluster solution, a single metal 1 atom oxide solution, a metal 1 sulfide cluster solution, and a metal 1 nitride solution, wherein the metal 1 element is selected from one or more of tungsten, molybdenum, iron, cobalt, and nickel.

[0014] As a further solution of the present invention: in step S2, the metal 2 compound is one of chloroauric acid, silver nitrate, and copper chloride;

[0015] As a further solution of the present invention: in step S2, the metal 2 and the metal 1 are mixed at a molar ratio of 45 to 182 (preferably 45.45 to 136.36);

[0016] As a further solution of the present invention: in step S2, the metal 1 single atom precursor solution and the metal 2 compound solution are mixed and then diluted so that the molar concentration of the metal 1 single atom precursor solution is 30 to 40 μM;

[0017] As a further solution of the present invention: in step S2, the pH is adjusted to 1.5-4.5 (preferably pH=2.5-4); the transparent container containing the mixed solution is placed in a UV light curing device for 5-10 minutes (preferably 5-8 minutes).

[0018] As a further scheme of the present invention: in step S3, the metal 2 nanoparticle sol is centrifugally cleaned with an acidic solvent with a pH of 2 to 5, preferably 3.5 to 4.5, or an organic solvent (one of anhydrous ethanol, isopropanol and ethylene glycol mixed with water in a certain ratio) (preferably isopropanol and water mixed in a ratio of 3:1 to 10:1).

[0019] As a further solution of the present invention: in step S3, the metal 2 nanoparticle sol after centrifugal washing is concentrated 10 to 100 times (preferably 80 to 90 times).

[0020] As a further solution of the present invention: in step S4, irradiating for several minutes is irradiating for 5 to 10 minutes, leaving it to stand for a period of time is leaving it to stand for 10 to 20 minutes (preferably 12 to 18 minutes), and repeating the irradiation cycle 0 to 6 times.

[0021] As a further solution of the present invention: in step S4, after the metal 2 nanoparticle multilayer surface enhanced Raman spectroscopy (SERS) substrate is prepared, it needs to be placed in an experimental environment with a relative humidity of 30% to 60% (preferably 40% to 50%) for self-assembly.

[0022] As a further solution of the present invention: in step S4, the solution of the substance to be tested can be dissolved or diluted with one or more of ethanol, ethylene glycol, isopropanol, and pure isopropanol.

[0023] As a further solution of the present invention: in step S5, the excitation wavelength of the Raman spectrum is 532-785nm (preferably 785nm), the laser power is 1-10mW (preferably 5-10mW), the integration time is 0.5-5s, and the spectral range is 450-1600cm -1 ; The Raman characteristic peak of the organic phosphorus compound dimethyl methyl phosphate (DMMP) has a Raman shift of 510 cm -1 and 710cm -1 (The main peak is 710cm -1 ), the Raman characteristic peak of diethyl chloromethyl phosphate (DECMP) is at a Raman shift of 660 cm -1 and 699cm -1 The Raman characteristic peak of malathion is at a Raman shift of 502 cm -1 and 821cm -1 Place.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention provides a SERS detection method for organophosphorus compounds DMMP, DECMP and malathion, which utilizes the high hot spot density and hot spot utilization rate of a multi-layer SERS substrate to achieve SERS quantitative detection of dimethyl methyl phosphate (DMMP), diethyl chloromethyl phosphate (DECMP) and malathion, with the detection limit and sensitivity both reaching 100 ppb (i.e. 0.1 ppm), and rapid detection can be completed within 5 minutes. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a SEM image of the gold nanoparticles photochemically synthesized in step (4) of Example 1.

[0027] Figure 2 is the SERS spectrum collected in step (10) of Example 1, from Figure 2 It can be seen that the SERS spectrum of the organophosphorus compound DMMP has a Raman shift of 510 cm -1 and 710cm -1 The peak is the characteristic peak of DMMP.

[0028] Figure 3 is the SERS spectrum collected in step (10) of Example 2, from Figure 3 It can be seen that the SERS spectra of DMMP with different concentrations of organophosphorus compounds have a Raman shift of 510 cm -1 and 710cm -1 The characteristic peak of DMMP is at Figure 3 It can be concluded that when the operating methods of Examples 2, 3, and 4 are the same, the minimum detection concentration of DMMP is 0.1 ppm.

[0029] Figure 4 is the SERS spectrum collected from step (10) of Example 1 and Comparative Examples 1, 2 and 3. Figure 4 It can be seen that the SERS spectra of the organophosphorus compound DMMP measured by different operation methods have a Raman shift of 510 cm -1 and 710cm -1 The characteristic peak of DMMP is at . Figure 4 It can be concluded that when the pH of the mixed solution is adjusted to 2.5, the Raman signal intensity of DMMP is the highest.

[0030] Figure 5 is the SERS spectrum collected in step (10) of Examples 1, 5, 6, 7 and 8, from Figure 5It can be seen that the SERS spectra of the organophosphorus compound DMMP measured by different operation methods have a Raman shift of 510 cm -1 and 710cm -1 The characteristic peak of DMMP is at Figure 5 It can be concluded that under the operating methods of Example 1 and Example 5, the Raman signal intensity of DMMP is the highest.

[0031] Figure 6 is the SERS spectrum collected in step (10) of Example 9, from Figure 6 It can be seen that the DECMP SERS spectra of organophosphorus compounds with different concentrations have a Raman shift of 660 cm -1 and 699cm -1 The peak at is the characteristic peak of DECMP. Figure 6 It can be concluded that when the operating methods of Examples 9 and 10 are the same, the minimum detection concentration of DECMP is 0.1 ppm.

[0032] Figure 7 is the SERS spectrum collected in step (10) of Example 11, from Figure 3 It can be seen that the SERS spectra of malathion with different concentrations of organophosphorus compounds, in which the Raman shift is at 502cm -1 and 821cm -1 The peak at is the characteristic peak of malathion. Figure 7 It can be concluded that when the operating methods of Examples 11 and 12 are the same, the minimum detection concentration of malathion is 0.1 ppm. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below in conjunction with specific implementation modes, but the protection scope of the present invention is not limited to the described contents.

[0034] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0035] Example 1

[0036] The SERS detection of DMMP with a concentration of 100 ppm was carried out, and the specific operation steps are as follows:

[0037] (1) Prepare and collect tungsten single atom precursor solution for later use.

[0038] (2) Take 0.5 mL of the above tungsten single atom precursor solution and add it to 15 mL of deionized water and continue stirring for 2 minutes, then add 90 μL of 25 mM chloroauric acid aqueous solution. Stir for 5 minutes under magnetic stirring at 800 r / min to fully mix the solution. At this time, the molar ratio of chloroauric acid aqueous solution to tungsten single atom precursor solution is 45.45.

[0039] (3) Adjust the pH of the mixed solution to 2.5.

[0040] (4) The beaker containing the mixed solution is placed in a UV light curing device for ultraviolet irradiation at a light intensity of 35% and a light irradiation time of 5 min to synthesize the gold nanoparticle sol.

[0041] (5) Mix isopropanol and water in a ratio of 3:1 and then centrifuge to clean the gold nanoparticle sol.

[0042] (6) The gold nanoparticle sol after centrifugal washing was concentrated 80 times.

[0043] (7) Soak the polished silicon wafer in a mixed solution of concentrated hydrochloric acid and concentrated nitric acid (aqua regia with a volume ratio of 3:1) for 30 minutes, and then rinse the silicon wafer with pure water.

[0044] (8) Place the silicon wafer with the polished surface facing up into a beaker containing the irradiated gold sol solution, and then place the beaker into a UV light curing device for 5 minutes. After the irradiation is completed, take out the beaker containing the gold sol and let it stand for 15 minutes. Then, place the beaker into the UV light curing device for 5 minutes again. After the irradiation is completed, take out the beaker containing the gold sol and let it stand for 20 minutes.

[0045] (9) After the silicon-based nanoparticle multilayer surface enhanced Raman spectroscopy (SERS) substrate is taken out, it needs to be placed in an experimental environment with a relative humidity of 45% for self-assembly.

[0046] (10) After the SERS substrate is dried, the solution of the substance to be tested is dripped onto the silicon wafer and detected by Raman spectroscopy. The excitation wavelength of the Raman spectrometer is 785 nm, the laser power is 10 mW, the integration time is 2 s, and the spectral range is 450-1600 cm -1 SERS spectra were collected under the conditions of .

[0047] The preparation method of tungsten single atom precursor is as follows:

[0048] The entire synthesis process was carried out in a 150 mL beaker with a dust cover and wrapped with tin foil to achieve light-proof conditions, and was always vigorously stirred with a magnetic stirring rotor. 3.0 g of sodium tungstate dihydrate powder was dissolved in 100 mL of deionized water, 20 mL of ethylene glycol was added thereto, and then 20% dilute sulfuric acid was added drop by drop to adjust the solution pH to 7. After the solution was fully stirred for 30 minutes, 10% dilute sulfuric acid was added drop by drop again, and ethylene glycol solution was added drop by drop at the same time, and the solution pH was slowly adjusted to 3.5. After the solution was fully stirred for 30 minutes, a tungsten single atom precursor solution was finally obtained.

[0049] Example 2

[0050] The SERS detection of DMMP with a concentration of 10 ppm was performed with the following specific steps:

[0051] (1) Prepare and collect tungsten single atom precursor solution for later use.

[0052] (2) Take 0.5 mL of the above tungsten single atom precursor solution and add it to 15 mL of deionized water and continue stirring for 2 min, then add 90 μL of 25 mM chloroauric acid aqueous solution. Stir for 5 min under magnetic stirring at 800 r / min to fully mix the solution. At this time, the molar ratio of chloroauric acid aqueous solution to tungsten single atom precursor solution is 45.45.

[0053] (3) Adjust the pH of the mixed solution to 2.5.

[0054] (4) The beaker containing the mixed solution was placed in a UV curing device for ultraviolet irradiation at a light intensity of 35% and a light irradiation time of 5 min.

[0055] (5) Mix isopropanol and water in a ratio of 3:1 and then centrifuge to clean the gold nanoparticle sol.

[0056] (6) The gold nanoparticle sol after centrifugal washing was concentrated 80 times.

[0057] (7) Soak the polished silicon wafer in a mixed solution of concentrated hydrochloric acid and concentrated nitric acid (aqua regia with a volume ratio of 3:1) for 30 minutes, and then rinse the silicon wafer with water.

[0058] (8) Place the silicon wafer with the polished surface facing up into a beaker containing the irradiated gold sol solution, and then place the beaker into a UV light curing device for 5 minutes. After the irradiation is completed, take out the beaker containing the gold sol and let it stand for 15 minutes. Then, place the beaker into the UV light curing device for 5 minutes again. After the irradiation is completed, take out the beaker containing the gold sol and let it stand for 20 minutes.

[0059] (9) After the silicon-based nanoparticle multilayer surface enhanced Raman spectroscopy (SERS) substrate is taken out, it needs to be placed in an experimental environment with a relative humidity of 45% for self-assembly.

[0060] (10) After the SERS substrate is dried, the solution of the substance to be tested is dripped onto the silicon wafer and detected by Raman spectroscopy. The excitation wavelength of the Raman spectrometer is 785 nm, the laser power is 10 mW, the integration time is 2 s, and the spectral range is 450-1600 cm -1 SERS spectra were collected under the conditions of .

[0061] Wherein, the method for preparing the tungsten single atom precursor solution in step (1) is the same as that in Example 1.

[0062] Example 3

[0063] The SERS detection of DMMP with a concentration of 1 ppm was performed with the following specific steps:

[0064] (1) Prepare and collect tungsten single atom precursor solution for later use.

[0065] (2) Take the above 0.5mL of tungsten single atom precursor solution and add it to 15mL of deionized water and continue stirring for 2min, then add 90μL of 25mM chloroauric acid aqueous solution. Stir for 5min under 800r / min magnetic stirring to fully mix the solution. At this time, the molar ratio of chloroauric acid aqueous solution to tungsten single atom precursor solution is 45.45. (3) Adjust the pH of the mixed solution to 2.5.

[0066] (4) The beaker containing the mixed solution was placed in a UV curing device for ultraviolet irradiation at a light intensity of 35% and a light irradiation time of 5 min.

[0067] (5) Mix isopropanol and water in a ratio of 3:1 and then centrifuge to clean the gold nanoparticle sol.

[0068] (6) The gold nanoparticle sol after centrifugal washing was concentrated 80 times.

[0069] (7) Soak the polished silicon wafer in a mixed solution of concentrated hydrochloric acid and concentrated nitric acid (aqua regia with a volume ratio of 3:1) for 30 minutes, and then rinse the silicon wafer with water.

[0070] (8) Place the silicon wafer with the polished surface facing up into a beaker containing the irradiated gold sol solution, and then place the beaker into a UV light curing device for 5 minutes. After the irradiation is completed, take out the beaker containing the gold sol and let it stand for 15 minutes. Then, place the beaker into the UV light curing device for 5 minutes again. After the irradiation is completed, take out the beaker containing the gold sol and let it stand for 20 minutes.

[0071] (9) After the silicon-based nanoparticle multilayer surface enhanced Raman spectroscopy (SERS) substrate is taken out, it needs to be placed in an experimental environment with a relative humidity of 45% for self-assembly.

[0072] (10) After the SERS substrate is dried, the solution of the substance to be tested is dripped onto the silicon wafer and detected by Raman spectroscopy. The excitation wavelength of the Raman spectrometer is 785 nm, the laser power is 10 mW, the integration time is 2 s, and the spectral range is 450-1600 cm -1 SERS spectra were collected under the conditions of .

[0073] Wherein, the method for preparing the tungsten single atom precursor solution in step (1) is the same as that in Example 1.

[0074] Example 4

[0075] The SERS detection of DMMP with a concentration of 0.1 ppm was performed with the following specific steps:

[0076] (1) Prepare and collect tungsten single atom precursor solution for later use.

[0077] (2) Take the above 0.5mL of tungsten single atom precursor solution and add it to 15mL of deionized water and continue stirring for 2min, then add 90μL of 25mM chloroauric acid aqueous solution. Stir for 5min under 800r / min magnetic stirring to fully mix the solution. At this time, the molar ratio of chloroauric acid aqueous solution to tungsten single atom precursor solution is 45.45. (3) Adjust the pH of the mixed solution to 2.5.

[0078] (4) The beaker containing the mixed solution was placed in a UV curing device for ultraviolet irradiation at a light intensity of 35% and a light irradiation time of 5 min.

[0079] (5) Mix isopropanol and water in a ratio of 3:1 and then centrifuge to clean the gold nanoparticle sol.

[0080] (6) The gold nanoparticle sol after centrifugal washing was concentrated 80 times.

[0081] (7) Soak the polished silicon wafer in a mixed solution of concentrated hydrochloric acid and concentrated nitric acid (aqua regia with a volume ratio of 3:1) for 30 minutes, and then rinse the silicon wafer with water.

[0082] (8) Place the silicon wafer with the polished surface facing up into a beaker containing the irradiated gold sol solution, and then place the beaker into a UV light curing device for 5 minutes. After the irradiation is completed, take out the beaker containing the gold sol and let it stand for 15 minutes. Then, place the beaker into the UV light curing device for 5 minutes again. After the irradiation is completed, take out the beaker containing the gold sol and let it stand for 20 minutes.

[0083] (9) After the silicon-based nanoparticle multilayer surface enhanced Raman spectroscopy (SERS) substrate is taken out, it needs to be placed in an experimental environment with a relative humidity of 45% for self-assembly.

[0084] (10) After the SERS substrate is dried, the solution of the substance to be tested is dripped onto the silicon wafer and detected by Raman spectroscopy. The excitation wavelength of the Raman spectrometer is 785 nm, the laser power is 10 mW, the integration time is 2 s, and the spectral range is 450-1600 cm -1 SERS spectra were collected under the conditions of .

[0085] Wherein, the method for preparing the tungsten single atom precursor solution in step (1) is the same as that in Example 1.

[0086] Example 5

[0087] The SERS detection of DMMP with a concentration of 100 ppm was carried out, and the specific operation steps are as follows:

[0088] (1) Prepare and collect tungsten single atom precursor solution for later use.

[0089] (2) 0.5 mL of the above tungsten single atom precursor solution was added to 15 mL of deionized water and stirred for 2 min, and then 135 μL of 25 mM chloroauric acid aqueous solution was added. The solution was stirred for 5 min under magnetic stirring at 800 r / min to fully mix the solution. At this time, the molar ratio of the chloroauric acid aqueous solution to the tungsten single atom precursor solution was 68.18.

[0090] (3) Adjust the pH of the mixed solution to 1.5.

[0091] (4) The beaker containing the mixed solution was placed in a UV curing device for ultraviolet irradiation at a light intensity of 40% and a light irradiation time of 5 min.

[0092] (5) Mix isopropanol and water in a ratio of 3:1 and then centrifuge to clean the gold nanoparticle sol.

[0093] (6) The gold nanoparticle sol after centrifugal washing was concentrated 80 times.

[0094] (7) Soak the polished silicon wafer in a mixed solution of concentrated hydrochloric acid and concentrated nitric acid (aqua regia with a volume ratio of 3:1) for 30 minutes, and then rinse the silicon wafer with water.

[0095] (8) Place the silicon wafer with the polished surface facing upward into a beaker containing the irradiated gold sol solution, and then place the beaker in a UV light curing device for 10 minutes. After the irradiation is completed, take out the beaker containing the gold sol and let it stand for 13 minutes. Then, place the beaker in the UV light curing device again for 5 minutes. After the irradiation is completed, take out the beaker containing the gold sol and let it stand for 20 minutes.

[0096] (9) After the silicon-based nanoparticle multilayer surface enhanced Raman spectroscopy (SERS) substrate is taken out, it needs to be placed in an experimental environment with a relative humidity of 45% for self-assembly.

[0097] (10) After the SERS substrate is dried, the solution of the substance to be tested is dripped onto the silicon wafer and detected by Raman spectroscopy. The excitation wavelength of the Raman spectrometer is 785 nm, the laser power is 10 mW, the integration time is 2 s, and the spectral range is 450-1600 cm -1 SERS spectra were collected under the conditions of .

[0098] Wherein, the method for preparing the tungsten single atom precursor solution in step (1) is the same as that in Example 1.

[0099] Example 6

[0100] The SERS detection of DMMP with a concentration of 100 ppm was carried out, and the specific operation steps are as follows:

[0101] (1) Prepare and collect tungsten single atom precursor solution for later use.

[0102] (2) Take 0.5 mL of the above tungsten single atom precursor solution and add it to 15 mL of deionized water and continue stirring for 2 min, then add 180 μL of 25 mM chloroauric acid aqueous solution. Stir for 5 min under magnetic stirring at 800 r / min to fully mix the solution. At this time, the molar ratio of chloroauric acid aqueous solution to tungsten single atom precursor solution is 90.9.

[0103] (3) Adjust the pH of the mixed solution to 2.5.

[0104] (4) The beaker containing the mixed solution was placed in a UV curing device for ultraviolet irradiation at a light intensity of 50% and a light exposure time of 5 min.

[0105] (5) Mix isopropanol and water in a ratio of 3:1 and then centrifuge to clean the gold nanoparticle sol.

[0106] (6) The gold nanoparticle sol after centrifugal washing was concentrated 80 times.

[0107] (7) Soak the polished silicon wafer in a mixed solution of concentrated hydrochloric acid and concentrated nitric acid (aqua regia with a volume ratio of 3:1) for 30 minutes, and then rinse the silicon wafer with water.

[0108] (8) Place the silicon wafer with the polished surface facing upward into a beaker containing the irradiated gold sol solution, and then place the beaker in a UV light curing device for 15 minutes. After the irradiation is completed, take out the beaker containing the gold sol and let it stand for 15 minutes. Then, place the beaker in the UV light curing device again for 5 minutes. After the irradiation is completed, take out the beaker containing the gold sol and let it stand for 20 minutes.

[0109] (9) After the silicon-based nanoparticle multilayer surface enhanced Raman spectroscopy (SERS) substrate is taken out, it needs to be placed in an experimental environment with a relative humidity of 45% for self-assembly.

[0110] (10) After the SERS substrate is dried, the solution of the substance to be tested is dripped onto the silicon wafer and detected by Raman spectroscopy. The excitation wavelength of the Raman spectrometer is 785 nm, the laser power is 10 mW, the integration time is 2 s, and the spectral range is 450-1600 cm -1 SERS spectra were collected under the conditions of .

[0111] Wherein, the method for preparing the tungsten single atom precursor solution in step (1) is the same as that in Example 1.

[0112] Example 7

[0113] The SERS detection of DMMP with a concentration of 100 ppm was carried out, and the specific operation steps are as follows:

[0114] (1) Prepare and collect tungsten single atom precursor solution for later use.

[0115] (2) 0.5 mL of the above tungsten single atom precursor solution was added to 15 mL of deionized water and stirred for 2 min, and then 225 μL of 25 mM chloroauric acid aqueous solution was added. The solution was stirred for 5 min under magnetic stirring at 800 r / min to fully mix the solution. At this time, the molar ratio of the chloroauric acid aqueous solution to the tungsten single atom precursor solution was 113.63.

[0116] (3) Adjust the pH of the mixed solution to 3.5.

[0117] (4) The beaker containing the mixed solution was placed in a UV curing device for ultraviolet irradiation at a light intensity of 60% for 10 min.

[0118] (5) Mix isopropanol and water in a ratio of 5:1 and then centrifuge to clean the gold nanoparticle sol.

[0119] (6) The gold nanoparticle sol after centrifugal washing was concentrated 90 times.

[0120] (7) Soak the polished silicon wafer in a mixed solution of concentrated hydrochloric acid and concentrated nitric acid (aqua regia with a volume ratio of 3:1) for 30 minutes, and then rinse the silicon wafer with water.

[0121] (8) Place the silicon wafer with the polished surface facing upward into a beaker containing the irradiated gold sol solution, and then place the beaker in a UV light curing device for 10 minutes. After the irradiation is completed, take out the beaker containing the gold sol and let it stand for 18 minutes. Then, place the beaker in the UV light curing device again for 5 minutes. After the irradiation is completed, take out the beaker containing the gold sol and let it stand for 20 minutes.

[0122] (9) After the silicon-based nanoparticle multilayer surface enhanced Raman spectroscopy (SERS) substrate is taken out, it needs to be placed in an experimental environment with a relative humidity of 45% for self-assembly.

[0123] (10) After the SERS substrate is dried, the solution of the substance to be tested is dripped onto the silicon wafer and detected by Raman spectroscopy. The excitation wavelength of the Raman spectrometer is 785 nm, the laser power is 10 mW, the integration time is 2 s, and the spectral range is 450-1600 cm -1 SERS spectra were collected under the conditions of .

[0124] Wherein, the method for preparing the tungsten single atom precursor solution in step (1) is the same as that in Example 1.

[0125] Example 8

[0126] The SERS detection of DMMP with a concentration of 100 ppm was carried out, and the specific operation steps are as follows:

[0127] (1) Prepare and collect tungsten single atom precursor solution for later use.

[0128] (2) Take 0.5 mL of the above tungsten single atom precursor solution and add it to 15 mL of deionized water and continue stirring for 2 min, then add 270 μL of 25 mM chloroauric acid aqueous solution. Stir for 5 min under magnetic stirring at 800 r / min to fully mix the solution. At this time, the molar ratio of chloroauric acid aqueous solution to tungsten single atom precursor solution is 136.36.

[0129] (3) Adjust the pH of the mixed solution to 4.5.

[0130] (4) The beaker containing the mixed solution was placed in a UV curing device for ultraviolet irradiation at a light intensity of 70% for 15 minutes.

[0131] (5) Mix isopropanol and water in a ratio of 10:1 and then centrifuge to clean the gold nanoparticle sol.

[0132] (6) The gold nanoparticle sol after centrifugal washing was concentrated 85 times.

[0133] (7) Soak the polished silicon wafer in a mixed solution of concentrated hydrochloric acid and concentrated nitric acid (aqua regia with a volume ratio of 3:1) for 30 minutes, and then rinse the silicon wafer with water.

[0134] (8) Place the silicon wafer with the polished surface facing upward into a beaker containing the irradiated gold sol solution, and then place the beaker in a UV light curing device for 10 minutes. After the irradiation is completed, take out the beaker containing the gold sol and let it stand for 15 minutes. Then, place the beaker in the UV light curing device again for 5 minutes. After the irradiation is completed, take out the beaker containing the gold sol and let it stand for 20 minutes.

[0135] (9) After the silicon-based nanoparticle multilayer surface enhanced Raman spectroscopy (SERS) substrate is taken out, it needs to be placed in an experimental environment with a relative humidity of 45% for self-assembly.

[0136] (10) After the SERS substrate is dried, the solution of the substance to be tested is dripped onto the silicon wafer and detected by Raman spectroscopy. The excitation wavelength of the Raman spectrometer is 785 nm, the laser power is 10 mW, the integration time is 2 s, and the spectral range is 450-1600 cm -1 SERS spectra were collected under the conditions of .

[0137] Wherein, the method for preparing the tungsten single atom precursor solution in step (1) is the same as that in Example 1.

[0138] Example 9

[0139] The SERS detection of DECMP with a concentration of 1 ppm was performed with the following specific steps:

[0140] (1) Prepare and collect tungsten single atom precursor solution for later use.

[0141] (2) Take 0.5 mL of the above tungsten single atom precursor solution and add it to 15 mL of deionized water and continue stirring for 2 min, then add 270 μL of 25 mM chloroauric acid aqueous solution. Stir for 5 min under magnetic stirring at 800 r / min to fully mix the solution. At this time, the molar ratio of chloroauric acid aqueous solution to tungsten single atom precursor solution is 136.36.

[0142] (3) Adjust the pH of the mixed solution to 4.5.

[0143] (4) The beaker containing the mixed solution was placed in a UV curing device for ultraviolet irradiation at a light intensity of 70% for 15 minutes.

[0144] (5) Mix isopropanol and water in a ratio of 10:1 and then centrifuge to clean the gold nanoparticle sol.

[0145] (6) The gold nanoparticle sol after centrifugal washing was concentrated 90 times.

[0146] (7) Soak the polished silicon wafer in a mixed solution of concentrated hydrochloric acid and concentrated nitric acid (aqua regia with a volume ratio of 3:1) for 30 minutes, and then rinse the silicon wafer with water.

[0147] (8) Place the silicon wafer with the polished surface facing upward into a beaker containing the irradiated gold sol solution, and then place the beaker in a UV light curing device for 10 minutes. After the irradiation is completed, take out the beaker containing the gold sol and let it stand for 15 minutes. Then, place the beaker in the UV light curing device again for 5 minutes. After the irradiation is completed, take out the beaker containing the gold sol and let it stand for 20 minutes.

[0148] (9) After the silicon-based nanoparticle multilayer surface enhanced Raman spectroscopy (SERS) substrate is taken out, it needs to be placed in an experimental environment with a relative humidity of 45% for self-assembly.

[0149] (10) After the SERS substrate is dried, the solution of the substance to be tested is dripped onto the silicon wafer and detected by Raman spectroscopy. The excitation wavelength of the Raman spectrometer is 785 nm, the laser power is 10 mW, the integration time is 2 s, and the spectral range is 450-1600 cm -1 SERS spectra were collected under the conditions of .

[0150] Wherein, the method for preparing the tungsten single atom precursor solution in step (1) is the same as that in Example 1.

[0151] Example 10

[0152] The SERS detection of DECMP with a concentration of 0.1 ppm was performed. The specific operation steps are as follows:

[0153] (1) Prepare and collect tungsten single atom precursor solution for later use.

[0154] (2) Take 0.5 mL of the above tungsten single atom precursor solution and add it to 15 mL of deionized water and continue stirring for 2 min, then add 270 μL of 25 mM chloroauric acid aqueous solution. Stir for 5 min under magnetic stirring at 800 r / min to fully mix the solution. At this time, the molar ratio of chloroauric acid aqueous solution to tungsten single atom precursor solution is 136.36.

[0155] (3) Adjust the pH of the mixed solution to 4.5.

[0156] (4) The beaker containing the mixed solution was placed in a UV curing device for ultraviolet irradiation at a light intensity of 70% for 15 minutes.

[0157] (5) Mix isopropanol and water in a ratio of 10:1 and then centrifuge to clean the gold nanoparticle sol.

[0158] (6) The gold nanoparticle sol after centrifugal washing was concentrated 90 times.

[0159] (7) Soak the polished silicon wafer in a mixed solution of concentrated hydrochloric acid and concentrated nitric acid (aqua regia with a volume ratio of 3:1) for 30 minutes, and then rinse the silicon wafer with water.

[0160] (8) Place the silicon wafer with the polished surface facing upward into a beaker containing the irradiated gold sol solution, and then place the beaker in a UV light curing device for 10 minutes. After the irradiation is completed, take out the beaker containing the gold sol and let it stand for 15 minutes. Then, place the beaker in the UV light curing device again for 5 minutes. After the irradiation is completed, take out the beaker containing the gold sol and let it stand for 20 minutes.

[0161] (9) After the silicon-based nanoparticle multilayer surface enhanced Raman spectroscopy (SERS) substrate is taken out, it needs to be placed in an experimental environment with a relative humidity of 45% for self-assembly.

[0162] (10) After the SERS substrate is dried, the solution of the substance to be tested is dripped onto the silicon wafer and detected by Raman spectroscopy. The excitation wavelength of the Raman spectrometer is 785 nm, the laser power is 10 mW, the integration time is 2 s, and the spectral range is 450-1600 cm -1 SERS spectra were collected under the conditions of .

[0163] Wherein, the method for preparing the tungsten single atom precursor solution in step (1) is the same as that in Example 1.

[0164] Embodiment 11

[0165] The SERS detection of malathion at a concentration of 1 ppm was performed with the following specific steps:

[0166] (1) Prepare and collect tungsten single atom precursor solution for later use.

[0167] (2) Take 0.5 mL of the above tungsten single atom precursor solution and add it to 15 mL of deionized water and continue stirring for 2 min, then add 270 μL of 25 mM chloroauric acid aqueous solution. Stir for 5 min under magnetic stirring at 800 r / min to fully mix the solution. At this time, the molar ratio of chloroauric acid aqueous solution to tungsten single atom precursor solution is 136.36.

[0168] (3) Adjust the pH of the mixed solution to 4.5.

[0169] (4) The beaker containing the mixed solution was placed in a UV curing device for ultraviolet irradiation at a light intensity of 70% for 15 minutes.

[0170] (5) Mix isopropanol and water in a ratio of 3:1 and then centrifuge to clean the gold nanoparticle sol.

[0171] (6) The gold nanoparticle sol after centrifugal washing was concentrated 90 times.

[0172] (7) Soak the polished silicon wafer in a mixed solution of concentrated hydrochloric acid and concentrated nitric acid (aqua regia with a volume ratio of 3:1) for 30 minutes, and then rinse the silicon wafer with water.

[0173] (8) Place the silicon wafer with the polished surface facing upward into a beaker containing the irradiated gold sol solution, and then place the beaker in a UV light curing device for 10 minutes. After the irradiation is completed, take out the beaker containing the gold sol and let it stand for 15 minutes. Then, place the beaker in the UV light curing device again for 5 minutes. After the irradiation is completed, take out the beaker containing the gold sol and let it stand for 20 minutes.

[0174] (9) After the silicon-based nanoparticle multilayer surface enhanced Raman spectroscopy (SERS) substrate is taken out, it needs to be placed in an experimental environment with a relative humidity of 45% for self-assembly.

[0175] (10) After the SERS substrate is dried, the solution of the substance to be tested is dripped onto the silicon wafer and detected by Raman spectroscopy. The excitation wavelength of the Raman spectrometer is 785 nm, the laser power is 10 mW, the integration time is 2 s, and the spectral range is 450-1600 cm -1 SERS spectra were collected under the conditions of .

[0176] Wherein, the method for preparing the tungsten single atom precursor solution in step (1) is the same as that in Example 1.

[0177] Example 12

[0178] The SERS detection of malathion with a concentration of 0.1 ppm was performed, and the specific operation steps are as follows:

[0179] (1) Prepare and collect tungsten single atom precursor solution for later use.

[0180] (2) Take 0.5 mL of the above tungsten single atom precursor solution and add it to 15 mL of deionized water and continue stirring for 2 min, then add 270 μL of 25 mM chloroauric acid aqueous solution. Stir for 5 min under magnetic stirring at 800 r / min to fully mix the solution. At this time, the molar ratio of chloroauric acid aqueous solution to tungsten single atom precursor solution is 136.36.

[0181] (3) Adjust the pH of the mixed solution to 4.5.

[0182] (4) The beaker containing the mixed solution was placed in a UV curing device for ultraviolet irradiation at a light intensity of 70% for 15 minutes.

[0183] (5) Mix isopropanol and water in a ratio of 3:1 and then centrifuge to clean the gold nanoparticle sol.

[0184] (6) The gold nanoparticle sol after centrifugal washing was concentrated 90 times.

[0185] (7) Soak the polished silicon wafer in a mixed solution of concentrated hydrochloric acid and concentrated nitric acid (aqua regia with a volume ratio of 3:1) for 30 minutes, and then rinse the silicon wafer with water.

[0186] (8) Place the silicon wafer with the polished surface facing upward into a beaker containing the irradiated gold sol solution, and then place the beaker in a UV light curing device for 10 minutes. After the irradiation is completed, take out the beaker containing the gold sol and let it stand for 15 minutes. Then, place the beaker in the UV light curing device again for 5 minutes. After the irradiation is completed, take out the beaker containing the gold sol and let it stand for 20 minutes.

[0187] (9) After the silicon-based nanoparticle multilayer surface enhanced Raman spectroscopy (SERS) substrate is taken out, it needs to be placed in an experimental environment with a relative humidity of 45% for self-assembly.

[0188] (10) After the SERS substrate is dried, the solution of the substance to be tested is dripped onto the silicon wafer and detected by Raman spectroscopy. The excitation wavelength of the Raman spectrometer is 785 nm, the laser power is 10 mW, the integration time is 2 s, and the spectral range is 450-1600 cm -1 SERS spectra were collected under the conditions of .

[0189] Wherein, the method for preparing the tungsten single atom precursor solution in step (1) is the same as that in Example 1.

[0190] Comparative Example 1

[0191] Compared with Example 1, the only difference is that in step (3), the pH of the mixed solution is adjusted to 1.5.

[0192] Comparative Example 2

[0193] Compared with Example 1, the only difference is that in step (3), the pH of the mixed solution is adjusted to 3.5.

[0194] Comparative Example 3

[0195] Compared with Example 1, the only difference is that in step (3), the pH of the mixed solution is adjusted to 4.5.

Claims

1. A SERS detection method for organophosphorus compounds DMMP, DECMP and malathion, characterized in that: The following steps are involved: S1, preparing a metal 1 single atom precursor solution, wherein the metal 1 single atom precursor solution contains an alcohol compound having reducing properties with metal 1; S2, adding the metal 2 compound solution dropwise to the metal 1 single atom precursor solution obtained in step S1 and diluting after stirring at a certain speed, using an organic solvent as the diluent, and adjusting the pH to be acidic, placing a transparent container such as a beaker containing the mixed solution in a UV light curing device for several minutes, and photochemically synthesizing a sol containing metal 2 nanoparticles of different particle sizes; S3, washing the metal 2 nanometer particle sol obtained in step S2 by centrifugation with an acidic solvent or an organic solvent, and concentrating the metal 2 nanometer particle sol after centrifugation washing. S4, immersing the silicon wafer in the metal 2 nanoparticle sol obtained in step S3, irradiating for several minutes, then stopping the irradiation and letting it stand for a period of time, irradiating for several minutes again, then stopping the irradiation and letting it stand for a period of time, repeating the irradiation-stopping the irradiation and letting it stand for a period of time, and thus preparing a gold nanoparticle multilayer surface enhanced Raman spectroscopy (SERS) substrate; S5. After the taken-out SERS substrate is dried, the solution of the substance to be tested is dripped onto the silicon wafer and detected by Raman spectroscopy.

2. The method according to claim 1, characterized in that In step S1, the metal 1 single atom precursor solution is one or more of a metal 1 single atom solution, a metal 1 oxide cluster solution, a single metal 1 atom oxide solution, a metal 1 sulfide cluster solution, and a metal 1 nitride solution, wherein the metal 1 element is selected from one or more of tungsten, molybdenum, iron, cobalt, and nickel.

3. The method according to claim 1, characterized in that In step S2, the metal 1 single atom precursor solution and the metal 2 compound can be diluted 10 to 1000 times, and the metal 2 compound is one of chloroauric acid, silver nitrate, and copper chloride; In step S2, the molar ratio of metal 2 to metal 1 is 45 to 182 (preferably 45.45 to 136.36); In step S2, the metal 1 single atom precursor solution is mixed with the metal 2 compound and then diluted so that the molar concentration of the metal 1 single atom precursor solution is 30-40 μM. In step S2, the pH is adjusted to 1.5-4.5 (preferably pH=2.5-4); the transparent container containing the mixed solution is placed in a UV light curing device for 5-10 minutes (preferably 5-8 minutes).

4. The method according to claim 1, characterized in that In step S3, the metal 2 nanoparticle sol is centrifugally washed with an acidic solvent having a pH of 2 to 5 or an organic solvent (one of anhydrous ethanol, isopropanol and ethylene glycol mixed with water in a certain ratio); In step S3, the metal 2 nanoparticle sol after centrifugal washing is concentrated 10 to 100 times.

5. The method according to claim 1, characterized in that In step S4, irradiating with light for several minutes is irradiating with light for 5 to 10 minutes, leaving it to stand for a period of time is leaving it to stand for 10 to 20 minutes (preferably 12 to 18 minutes), and the irradiating with light is repeated 0 to 6 times.

6. The method according to claim 1, characterized in that In step S4, after the multilayer surface enhanced Raman spectroscopy (SERS) substrate containing metal 2 nanoparticles is prepared, it needs to be placed in an experimental environment with a relative humidity of 30% to 60% for self-assembly.

7. The method according to claim 1, characterized in that In step S5, the solution of the substance to be tested is diluted with an organic solvent selected from the group consisting of ethanol, ethylene glycol, and isopropanol, or pure water.

8. The method according to claim 1, characterized in that In step S5, the excitation wavelength of the Raman spectrum is 532-785 nm, the laser power is 1-10 mW, the integration time is 0.5-5 s, and the spectral range is 450-1600 cm -1 .

9. The method according to claim 1, characterized in that The Raman characteristic peak of the organic phosphorus compound dimethyl methyl phosphate (DMMP) is at a Raman shift of 510 cm -1 and 710cm -1 (The main peak is 710cm -1 ), the Raman characteristic peak of diethyl chloromethyl phosphate (DECMP) is at a Raman shift of 660 cm -1 and 699cm -1 The Raman characteristic peak of malathion is at a Raman shift of 502 cm -1 and 821cm -1 Place.

10. The method according to claim 1, characterized in that Both the detection limit and sensitivity can reach 100 ppb (i.e. 0.1 ppm), and rapid detection can be completed within 5 minutes.

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