CN112113950A

CN112113950A - Method for rapidly detecting sulfur dioxide residue in traditional Chinese medicine for sulfur fumigation

Info

Publication number: CN112113950A
Application number: CN202010940910.3A
Authority: CN
Inventors: 范骁辉; 程翼宇; 王毅
Original assignee: Zhejiang University ZJU
Current assignee: Zhejiang University ZJU
Priority date: 2020-09-09
Filing date: 2020-09-09
Publication date: 2020-12-22

Abstract

The invention discloses a method for rapidly detecting sulfur dioxide residue in a sulfitation traditional Chinese medicine, and belongs to the field of medicine analysis and traditional Chinese medicine quality evaluation methods. The method comprises the following steps: (1) preparing a Si @ Ag @ PEI composite membrane substrate; (2) adding a sample to be detected and an extracting solution into a headspace extracting device, taking a Si @ Ag @ PEI composite membrane substrate as a solid phase extracting material, and adsorbing a target object sulfur dioxide by adopting a headspace extracting method; (3) and detecting by adopting a surface enhanced Raman spectroscopy technology to obtain a Raman spectrogram of the sample to be detected, and calculating the sulfur dioxide residue in the sample to be detected by contrasting with a standard curve. The Si @ Ag @ PEI composite membrane substrate can adsorb SO₂Gas, and displays characteristic Raman peak, simultaneously enhances Raman signal intensity, and achieves detection limit of 1ppm, thereby realizing trace SO₂Specific detection of (3). The method is suitable for field detection environment, and can realize rapid evaluation of quality of raw materials and decoction pieces.

Description

Method for rapidly detecting sulfur dioxide residue in traditional Chinese medicine for sulfur fumigation

Technical Field

The invention belongs to the field of drug analysis and traditional Chinese medicine quality evaluation methods, and particularly relates to a method for detecting sulfur dioxide residue in a sulfitation traditional Chinese medicine based on an SERS (surface enhanced Raman scattering) technology.

Background

The Surface Enhanced Raman Spectroscopy (SERS) technology is developed on the Raman spectroscopy technology, and the Raman signal of the gold and silver nanoparticle is exponentially enhanced by adsorbing a molecule to be detected to the surface of the gold and silver nanoparticle, so that the Surface Enhanced Raman Spectroscopy (SERS) technology has wide application in the fields of chemistry, material analysis, environment and food safety, biological medicine and the like due to the advantages of high sensitivity, strong specificity, no fluorescence bleaching, no need of complex pretreatment and the like.

Patent document CN 104165878A discloses a method for detecting sulfur dioxide content in wine, which comprises preparing a macroscopic planar zinc oxide nano material as an adsorbing material for headspace solid phase extraction, enriching silica in wine, and detecting with surface enhanced raman spectroscopy.

Patent document CN 108444995 a discloses a method for rapidly detecting sulfur dioxide in wine on site, which comprises the following steps: (1) placing the reduced graphene solution, 4-mercaptopyridine and gold nanorods in a PBS (phosphate buffer solution) at room temperature, centrifuging and washing to obtain AuNRs/rGO-MPy; (2) AuNRs/rGO-MPy is filtered by an Anodisc filter membrane to obtain an AuNRs/rGO-MPy filter membrane, a headspace sampling-paper-based analysis device is constructed by combining a Karl Fischer reagent, and an ultraviolet spectrophotometer and a portable Raman spectrometer are used for detecting sulfur dioxide.

In recent years, the market scale of Chinese traditional medicine is continuously enlarged, the annual growth rate of the decoction piece market is higher than that of the medicine industry, but the problem of the quality safety of the Chinese traditional medicine is still serious. The main quality problems include inconsistent shape, low effective components, excessive sulfur dioxide residue, excessive heavy metals, dyeing, weight increment, adulteration and the like, wherein sulfur fumigation is more prominent. The traditional detection method for evaluating the quality of the traditional Chinese medicine mainly applies the technologies of chromatography, mass spectrum, atomic absorption spectrum and the like, has the advantages of sensitivity and accuracy, but has long pretreatment time of samples, mostly depends on large-scale instruments, and is not suitable for on-site rapid detection.

The Surface Enhanced Raman Spectroscopy (SERS) technology has the advantages of high sensitivity, real-time and rapid detection and the like, so that the SERS has the potential for rapid detection of the quality of traditional Chinese medicines. The Raman signal of the analyte depends on the stability of the enhanced substrate, and the development of a substrate material suitable for detecting complex matrix samples such as raw medicinal materials, decoction pieces and the like is a problem to be solved by the technical personnel in the field.

Disclosure of Invention

The invention aims to provide a substrate material suitable for detecting sulfur dioxide residue in traditional Chinese medicinal materials by an SERS (surface enhanced Raman scattering) technology so as to realize rapid evaluation of the quality of the raw medicinal materials and decoction pieces.

In order to achieve the aim, the invention provides a method for rapidly detecting sulfur dioxide residue in a sulfur-smoked traditional Chinese medicine, which comprises the following steps:

(1) preparing a Si @ Ag @ PEI composite membrane substrate: placing the clean silicon wafer in HF solution to remove silicon dioxide oxide layer to obtain hydrogenated silicon wafer, and placing the hydrogenated silicon wafer in a solution containing AgNO₃Reacting with a mixed solution of HF to obtain Si @ AgNPs, then dropwise adding a branched polyethyleneimine aqueous solution to enable the branched polyethyleneimine aqueous solution to be flatly paved on the surface of the Si @ AgNPs, and naturally airing to obtain a Si @ Ag @ PEI composite membrane substrate;

(2) adding a sample to be detected and an extracting solution into a headspace extracting device, taking a Si @ Ag @ PEI composite membrane substrate as a solid phase extracting material, and adsorbing a target object sulfur dioxide by adopting a headspace extracting method;

(3) and after extraction is finished, taking out the Si @ Ag @ PEI composite membrane substrate, detecting by adopting a surface enhanced Raman spectroscopy technology to obtain a Raman spectrogram of the sample to be detected, and calculating the sulfur dioxide residue in the sample to be detected by contrasting with a standard curve.

The traditional Chinese medicine comprises traditional Chinese medicine materials and traditional Chinese medicine decoction pieces.

In the step (1), a Si @ Ag @ PEI composite membrane substrate is prepared as a solid-phase extraction material. Branched Polyethyleneimine (PEI) has good acid gas (CO) due to rich amine groups₂，SO₂，NO₂) Adsorption capacity, and SO₂Characteristic Raman peak position (612 cm)^-1，910cm^-1) Can not be coated by CO₂(1285cm^-1，1388cm^-1) And NO₂(810cm^-1，1280cm^-1) Interference, can realize SO₂And (4) detecting the residual specificity.

The silicon wafer is a single-side polished silicon wafer of a crystal form 100, and is sequentially subjected to ultrasonic treatment in acetone, absolute ethyl alcohol and ultrapure water for 10min to remove organic matters, dust and the like on the surface of the silicon wafer, so that a clean silicon wafer is obtained.

The HF solution has a concentration of 5% by volume. The silicon chip is soaked in HF solution to remove the surface oxide layer and form Si-H bond.

The hydrogenated silicon wafer reacts with a soluble silver salt to deposit silver nanoparticles on the surface of the silicon wafer. Preferably, the mixed solution contains 2.5mM AgNO₃And 5% by volume of HF, and placing the hydrogenated silicon wafer in the mixed solution for oscillation reaction for 1.5-10 min. More preferably, the hydrogenated silicon wafer is placed in the mixed solution and reacted for 5min with shaking at 200 rpm.

The prepared Si @ AgNPs are stored in water, and are prevented from being oxidized after being stored in the air for a long time. When in use, the product is taken out and placed on filter paper to absorb moisture, and is used after the residual moisture is volatilized.

Preferably, the molecular weight of the branched polyethyleneimine is 600-70000. More preferably, branched polyethyleneimine with the molecular weight of 10000 is adopted, and a substrate synthesized by the material is used for SO₂Raman response is strongest.

The mass percentage concentration of the branched polyethyleneimine aqueous solution is 0.1-5%. Preferably, the branched polyethyleneimine aqueous solution is used at a concentration of 0.2 to 2, and more preferably, the branched polyethyleneimine aqueous solution has a concentration of 0.5%.

In the step (2), the Si @ Ag @ PEI composite membrane substrate is placed in a portable headspace extraction device, and the Si @ Ag @ PEI composite membrane substrate is used as an extraction material for SO in a sample to be detected₂And (5) carrying out adsorption enrichment.

Further, the extraction device is slightly modified so as to facilitate the placement of the substrate, specifically, a glass bottle with a screw cap is used as an extraction bottle, polylactic acid is used as a material to 3D print an -shaped hook-shaped extraction platform, and the extraction platform is vertically adhered to the inner side of the screw cap of the glass bottle and used for placing the Si @ Ag @ PEI composite film substrate.

The extracting solution is H with the volume percentage concentration of 0.1-20 percent₂SO₄The solution was prepared by adding 4mL of the extract to 1g of the sample.

Suspending the sealed extraction bottle in a water bath, and heating to extract SO₂. Preferably, the temperature of the headspace extraction is 30-90 ℃, and the extraction time is 5-30 min. More preferably, the headspace extraction conditions are: h with the volume percentage concentration of 5 percent is adopted₂SO₄The solution is used as extractive solution, and extracted at 75 deg.C for 15 min.

In the step (3), after extraction is finished, the Si @ Ag @ PEI composite membrane substrate is taken out, a handheld Raman instrument is used for detection, a Raman spectrogram of a sample to be detected is obtained, and SO is contrasted₂The detection limit can be used for judging whether the sample to be detected contains SO₂(ii) a Or calculating the sulfur dioxide content in the sample to be detected by contrasting the standard curve.

The standard curve drawing method comprises the following steps: na with a series of gradient concentrations₂SO₃Standard solution, SO according to the above procedure₂Headspace extraction and Raman detection at 612cm^-1To SO₂Characteristic Raman peak height and corresponding SO₂Linear regression of concentration values to obtain SO₂A standard curve.

The invention has the following beneficial effects:

(1)SO₂the content is an important index for evaluating the quality safety of the traditional Chinese medicine, and the Si @ Ag @ PEI composite membrane substrate provided by the invention can adsorb SO₂Gas at 612cm^-1The characteristic Raman peak is displayed, the Raman signal intensity is enhanced, the detection limit reaches 1ppm, and therefore trace SO is realized₂The method can be used for detecting the specificity of the Chinese medicine residue in the stoving and evaluating the quality.

(2) Aiming at the problem of sulfur dioxide residue in traditional Chinese medicines, the invention designs and prepares a functional material, combines a film microextraction technology, well separates components to be detected from complex traditional Chinese medicines, and improves the quantitative detection capability, and meanwhile, a handheld Raman spectrometer is adopted, so that the detection method is suitable for an on-site detection environment, thereby overcoming the defects of long time consumption and high instrument cost of the traditional detection method, and realizing the rapid evaluation of the quality of raw medicinal materials and decoction pieces.

Drawings

FIG. 1 shows the result of optimizing the synthesis time of Si @ AgNPs; wherein (a) is 10^-6M R6 solution 6G SERS patterns on Si @ AgNPs substrates at different synthesis durations, and (b) SERS patterns at 1510cm in different synthesis durations^-1Characteristic peak raman spectrum intensity at R6G. Raman shift denotes Raman shift (cm)^-1) Raman intensity (a.u.) chartThe Raman spectrum intensity is shown below.

FIG. 2-1 is a graph of the repeatability of a random point-picking survey of the surface of a Si @ AgNPs substrate; wherein (a) is 10^-6M R6 solution 6G random point-taking SERS graph on Si @ AgNPs substrate, and (b) graph is 1510cm in SERS graph^-1Characteristic peak raman spectrum intensity at R6G.

FIG. 2-2 is a graph of repeatability of the Si @ AgNPs substrate across batches; wherein (a) is 10^-6M R6G solution SERS patterns on different batches of Si @ AgNPs substrates, and (b) pattern is 1510cm in SERS pattern^-1Characteristic peak raman spectrum intensity at R6G.

FIG. 3 shows the result of Si @ AgNPs enhancement factor investigation.

FIG. 4 shows the results of stability studies of Si @ AgNPs; wherein (a) is 10^-6M R6G solution on a Si @ AgNPs substrate placed at different times, and (b) is 1510cm in the SERS diagram^-1Characteristic peak raman spectrum intensity at R6G.

FIG. 5 shows the optimization result of PEI concentration in the synthesis of the Si @ Ag @ PEI composite membrane substrate; wherein (a) is SO₂SERS plots on substrates synthesized with different concentrations of PEI, and (b) plot is 612cm in SERS plot^-1To SO₂Characteristic peak raman spectral intensity; concentration (PEI,%) represents the PEI Concentration (%).

FIG. 6 shows the optimization result of the molecular weight of PEI in the synthesis of the Si @ Ag @ PEI composite membrane substrate; wherein (a) is SO₂SERS patterns on substrates synthesized with PEI of different molecular weights, and (b) pattern is 612cm in SERS pattern^-1To SO₂Characteristic peak raman spectral intensity; (PEI) M.W. indicates PEI molecular weight.

FIG. 7-1 is a representation of a Si @ AgNPs scanning electron microscope; wherein, the figure (a) is an SEM figure under the magnification of 1000 times, and the figure (b) is an SEM figure under the magnification of 10000 times.

FIG. 7-2 is a representation of a scanning electron microscope of Si @ Ag @ PEI.

FIG. 8 is a headspace film adsorption method for SO detection₂Optimizing the content extraction condition; wherein (a) is SO extracted at different temperatures₂SERS plot on Si @ Ag @ PEI substrate, Temperature (deg.C) represents extraction Temperature (deg.C); (b) the SO at different extraction times is shown in the figure₂On a Si @ Ag @ PEI substrateTop SERS plot, time (min) denotes extraction time (min); (c) the graph shows different concentrations H₂SO₄Extracted SO₂SERS patterns on Si @ Ag @ PEI substrates, H₂SO₄The concentration (%) of the extract solution is shown.

FIG. 9 is a diagram of SO detection on a Si @ Ag @ PEI composite membrane substrate₂The detection limit and linear range of the content are inspected; wherein (a) is SO₂SERS graph of standard solution on Si @ Ag @ PEI substrate, and (b) graph of trace concentration SO₂SERS graph of standard solution on Si @ Ag @ PEI substrate, and (c) graph is 612cm in SERS graph^-1To SO₂Characteristic peak Raman spectrum intensity and SO₂Fitted curve of Concentration, Concentration (SO)₂Ppm) represents SO₂Concentration (ppm).

FIG. 10 is a diagram of SO detection on a Si @ Ag @ PEI composite membrane substrate₂The stability of the content is investigated; wherein (a) is SO₂SERS patterns of the solution on Si @ Ag @ PEI substrate placed for different days, and (b) pattern is 612cm in the SERS patterns^-1To SO₂Characteristic peak raman spectral intensity, time (day) denotes the time of placement (day).

FIG. 11 shows SO in Chinese medicinal materials such as Ginseng radix, Saviae Miltiorrhizae radix, semen Armeniacae amarum and rhizoma Dioscoreae tablet₂And (5) detecting the content.

FIG. 12-1 shows the herb of bitter apricot kernel SO₂Adding a mark and detecting a result; wherein, SO₂(mg/kg) represents SO₂Standard concentration (mg/kg) was added.

FIG. 12-2 shows Ginseng radix SO₂And adding a mark and detecting a result.

FIG. 12-3 shows the herb Salviae Miltiorrhizae SO₂And adding a mark and detecting a result.

Detailed Description

The present invention will be described in further detail with reference to specific examples, but the scope of the present invention is not limited thereto.

Example 1

Synthesizing Si @ AgNPs, comprising the following steps:

polishing a single-side polished silicon wafer of the crystal form 100, and sequentially performing ultrasonic treatment in acetone, absolute ethyl alcohol and ultrapure water for 10min to remove organic matters, dust and the like on the surface of the silicon wafer; soaking clean silicon wafer in 5% HF solution for 30min to remove the surface silicon dioxide oxide layer and form Si-H bond; hydrogenated silicon wafer was placed in a chamber containing 2.5mM AgNO₃Shaking at 200rpm in a small culture dish containing 5% HF mixed solution for 5min, replacing ultrapure water solution to terminate the reaction to obtain Si @ AgNPs, and storing in water to avoid oxidation after long-term storage in air; when in use, the product is taken out and placed on filter paper to absorb moisture, and is used after the residual moisture is volatilized.

Example 2

Investigating the influence of the reaction time on the synthesis effect of Si @ AgNPs:

the synthesis process of Si @ AgNPs in example 1 was repeated with shaking times of 1.5min, 3min, 5min, 10min, respectively. Soaking the Si @ AgNPs substrate in 10 at different reaction times^-6And (2) washing redundant R6G molecules on the surface by using clear water after the M rhodamine 6G (R6G) solution is taken out for 2 hours, scanning a Raman spectrum under a portable Raman spectrometer, judging the enhancement effect of the SERS of the substrate under different reaction time according to the characteristic peak height of R6G, and taking the enhancement effect as the selection basis of the reaction time. Raman spectrum parameter conditions are as follows: the power is 300mW, the integration time is 2s, and the integration times are 1.

The results of the examination are shown in FIG. 1. As can be seen from FIG. 1, the Raman enhancement performance is better when the reaction time of Si @ AgNPs is 5 min.

Example 3

And (3) inspecting the repeatability of the performance of the Si @ AgNPs:

the Si @ AgNPs substrate prepared in example 1 was immersed in 10^-6M R6G solution for 2h, and after being rinsed with clear water, the Raman spectrum is scanned by a portable Raman spectrometer. Randomly taking 10 points of the same substrate 1 to scan the spectrum to investigate the repeatability of randomly taking points of the substrate; spectra were scanned separately for 5 substrates in different batches, with 10 random points per 1 substrate and averaged to examine substrate batch-to-batch reproducibility.

The results of the examination are shown in FIGS. 2-1 and 2-2. As can be seen from FIG. 2-1, the random point taking repeatability of the Si @ AgNPs substrate is good; as can be seen in FIG. 2-2, the Si @ AgNPs substrate had good lot-to-lot reproducibility.

Example 4

Calculating the enhancement factor of the Si @ AgNPs:

preparation of the product in example 1Prepared Si @ AgNPs substrate is dripped with 10 mu L10^-6M R6 molecules (6G) and 10. mu.L of 0.1M R6 molecules (6G) are added dropwise to a blank silicon wafer, and after 2h, the Raman spectrum is measured under the same parameter conditions. According to the formula EF ═ I_SERS/N_SERS)/(I_bulk/N_bulk) At 1510cm^-1The raman peak intensity at (a) calculates the raman enhancement factor of the substrate.

The results are shown in FIG. 3. The enhancement factor of the Si @ AgNPs substrate, which can be calculated from FIG. 3, is 1.6X 10⁶。

Example 5

Investigating the stability of the performance of Si @ AgNPs:

batches of Si @ AgNPs substrates were prepared as in example 1, by first immersing 3 substrates in 10^-6M R6 Raman spectrum of 24h later scanned from 6G solution, which is marked as Day 1, and then every 3, 5 or 10 days, the Raman spectrum of the substrate is collected according to the above operation, and the stability of the Raman enhancement performance of the Si @ AgNPs substrate when the substrate is placed for 1, 3, 5, 10, 15, 20 or 30 days is respectively examined. Raman spectrum parameter conditions are as follows: the power is 150mW, the integration time is 1s, and the integration times are 1.

The results of the examination are shown in FIG. 4. As can be seen from fig. 4, the SERS detection performance of the Si @ AgNPs substrate remained stable for 30 days.

Example 6

A Si @ Ag @ PEI composite membrane substrate is synthesized, and the method comprises the following steps:

and dripping 10 mu L of 0.5% PEI aqueous solution to enable the surface of the Si @ AgNPs to be paved, and naturally airing to obtain the SERS-based Si @ Ag @ PEI composite membrane substrate.

Example 7

Detection of SO by headspace membrane adsorption method₂The method comprises the following steps:

a glass vial with a screw cap, having a volume of 20mL, was slightly modified to serve as a portable headspace extraction device: the method is characterized in that polylactic acid is used as a material of an -shaped hook-shaped extraction platform with the diameter of 1cm of a 3D printing platform, and the extraction platform is vertically adhered to the inner side of a glass bottle spiral cover and used for placing a Si @ Ag @ PEI substrate.

Adding 4mL of 5% H into the headspace extraction flask₂SO₄Adding 1mL of the prepared 100ppm Na₂SO₃And (3) standard solution, placing the Si @ Ag @ PEI substrate on an extraction table, screwing a bottle stopper, inserting the extraction bottle into a self-made perforated foam plate, suspending the foam plate in a water bath, and heating and extracting at the extraction temperature of 75 ℃ for 15 min.

And (3) taking out the Si @ Ag @ PEI substrate after headspace extraction, placing the substrate on a portable Raman detection table, scanning a Raman spectrum, randomly taking 3 points from each substrate, and carrying out parallel detection for 3 times. Raman spectral parameters: 150mW, integration time 2s and integration times 1.

Example 8

Investigating the influence of PEI concentration on the synthetic effect of the Si @ Ag @ PEI composite membrane substrate:

the synthesis of Si @ Ag @ PEI in example 6 was repeated, wherein PEI molecules were added dropwise at concentrations of 0, 0.1%, 0.2%, 0.5%, 1%, 2%, 3%, 5%, respectively. To SO₂And (5) headspace extraction adsorption, and selecting optimal conditions according to Raman detection.

The results of the examination are shown in FIG. 5. As can be seen in FIG. 5, the substrate pair SO synthesized at a PEI molecule concentration of 0.5% was₂The Raman response is strongest, SO PEI with the concentration diluted to 0.5% is selected as SO₂Adsorbing the material.

Example 9

Investigating the influence of the molecular weight of PEI on the synthesis effect of the Si @ Ag @ PEI composite membrane substrate:

the procedure of Si @ Ag @ PEI in example 6 was repeated, wherein the concentration of the dropwise added PEI molecule was 0.5% and the molecular weights of the PEI were changed to 600, 10k, 25k, 70k, respectively. To SO₂And (5) headspace extraction adsorption, and selecting optimal conditions according to Raman detection.

The results of the examination are shown in FIG. 6. As can be seen from FIG. 6, the substrate pair SO synthesized when the molecular weight of PEI is 10k₂The Raman response is strongest, SO PEI with the molecular weight of 10k is selected as SO₂Adsorbing the material.

Example 10

SEM characterization of Si @ AgNPs and Si @ Ag @ PEI substrates:

after the Si @ AgNPs and Si @ Ag @ PEI substrates optimized in reaction conditions are pretreated by drying and gold spraying, a double-sided adhesive tape is stuck on a sample table of a scanning electron microscope, and the appearance of the substrates is observed in the electron microscope. The electron microscope model is ZEISS GeminiSEM 300 field emission scanning electron microscope, the voltage is 3.00kV, and the magnification is 1k and 10k respectively.

The characterization results are shown in FIGS. 7-1 and 7-2. FIG. 7-1 is an SEM image of Si @ AgNPs, where the AgNPs can be seen to be uniformly distributed on the surface of the silicon wafer; FIG. 7-2 is an SEM image of Si @ Ag @ PEI.

Example 11

Optimizing SO₂Headspace extraction conditions:

example 7 was repeated for SO detection by headspace membrane adsorption₂The content method comprises the steps of extracting at 30 ℃, 45 ℃, 60 ℃, 75 ℃ and 90 ℃, and selecting the optimal conditions according to Raman detection.

Example 7 was repeated for SO detection by headspace membrane adsorption₂The content method comprises extracting for 5min, 10min, 15min, 20 min and 30min, and selecting optimal conditions according to Raman detection.

Example 7 was repeated for SO detection by headspace membrane adsorption₂Method of content, extraction of H added in a headspace extraction flask₂SO₄The concentrations of the solutions are 0.1%, 1%, 5%, 10% and 20%, respectively, and the optimal conditions are selected according to Raman detection.

The optimization results are shown in fig. 8. As can be seen from FIG. 8, the Raman signal is strongest at an extraction temperature of 75 ℃; when the extraction time is about 15min, the Raman amplification signal tends to be flat; h₂SO₄The raman signal is strongest at a solution concentration of 5%. The final extraction conditions were therefore 5% H₂SO₄Extracting at 75 deg.C for 15 min.

Example 12

Method linear range and detection limit investigation:

using optimised H₂SO₄Extracting with solution concentration, extraction time and temperature under the conditions of SO₂The detection linear range and detection limit were examined. Weighing Na₂SO₃0.2000g in 40mL of ultrapure water to give 500ppm of Na₂SO₃Stock solutions, and sequentially diluted to 100, 50, 10, 5, 1, 0.5 ppm. For a series of gradient concentrations of Na₂SO₃SO in solution₂Headspace extraction and Raman detectionAnd 3 parts are parallelly detected. Due to SO₂Molecular mass about Na₂SO₃1/2 of (1), SO₂Concentrations were approximately 250, 50, 25, 5, 2.5, 0.5, 0.25 ppm. At 612cm^-1To SO₂Characteristic Raman peak height and corresponding SO₂Linear regression of concentration values to obtain SO₂Detecting the linear range and simultaneously obtaining the slope k of the fitting curve; mixing Na₂SO₃The solution was changed to aqueous solution as a blank, and 9 Raman spectra were measured in parallel and calculated at 612cm^-1Standard deviation σ of the raman peak height; and calculating the detection limit LOD according to the formula LOD which is 3 sigma/k.

The results of the examination are shown in FIG. 9. According to different SO in FIGS. 9(a), (b)₂Concentration of Raman signal, the fitted curve of FIG. 9(c) was plotted to obtain SO₂The linear range of (A) is 2.5-250 ppm; the detection limit was 1 ppm.

Example 13

Investigating the stability of the Si @ Ag @ PEI substrate:

preparing batches of Si @ Ag @ PEI substrates, and performing SO on 3 sheets at 0, 7, 14 and 21 days respectively under the same conditions₂And (5) extracting and detecting.

The results of the examination are shown in FIG. 10. As can be seen from FIG. 10, the SERS detection performance of the Si @ Ag @ PEI substrate can be stably maintained for more than 20 days.

Example 14

SO in Chinese medicinal materials₂Detection of (2):

example 7 was repeated for SO detection by headspace membrane adsorption₂The content method comprises adding 1.0g rhizoma Dioscoreae tablet, semen Armeniacae amarum, and cut radix Ginseng or Saviae Miltiorrhizae radix into a headspace extraction bottle, respectively, without adding Na₂SO₃And (3) solution. Raman detection result and SO₂Comparing the detection limit to judge whether there is SO₂And (4) remaining.

The detection results are shown in fig. 11. Rhizoma Dioscoreae slice and Atractylodis rhizoma at 612cm^-1There is a distinct peak pattern, while American ginseng and bitter apricot seed have almost no peak at this position. The analytical results are shown in the following table.

TABLE 1 commercially available crude SO₂Residue detection

Example 15

Chinese herbal medicine SO₂Labeling and detecting:

example 7 was repeated for SO detection by headspace membrane adsorption₂The content method comprises adding semen Armeniacae amarum 1.0g, and Ginseng radix or Saviae Miltiorrhizae radix cut into short segments into a headspace extraction bottle, respectively, and uniformly adding 200 μ L Na with concentration of 1000, 250, 50ppm₂SO₃Standing the solution for 30min to obtain SO₂Adding medicinal material samples with standard concentration of 100 ppm, 25ppm and 5ppm respectively. Each medicinal material was added with standard concentration and operated in parallel for 3 portions, and the recovery rate was calculated.

The detection results are shown in FIG. 12-1, FIG. 12-2, and FIG. 12-3. The analysis results are shown in the following table, the standard recovery rate of the 3 medicinal materials is in the range of 81.2-110.5%, and the RSD is less than 20%.

TABLE 2 crude drug SO₂Sample adding recovery detection

It should be noted that variations and modifications can be made by those skilled in the art without departing from the principle of the present invention, and the protection scope of the present invention should be considered.

Claims

1. A method for rapidly detecting sulfur dioxide residue in a traditional Chinese medicine with sulfur fumigation is characterized by comprising the following steps:

2. The method for rapidly detecting sulfur dioxide residue in Chinese medicine fumigated with sulfur according to claim 1, wherein in step (1), the mixed solution contains 2.5mM AgNO₃And HF with the volume percentage concentration of 5%, and placing the hydrogenated silicon wafer in the mixed solution for oscillation reaction for 1.5-10 min.

3. The method of claim 2, wherein the hydrogenated silicon wafer is placed in the mixed solution at 200rpm for 5min of oscillating reaction.

4. The method for rapidly detecting the sulfur dioxide residue in the sulfur-fumigated traditional Chinese medicine as claimed in claim 1, wherein in the step (1), the molecular weight of the branched polyethyleneimine is 600-70000.

5. The method for rapidly detecting the sulfur dioxide residue in the sulfitation traditional Chinese medicine as claimed in claim 1, wherein in the step (1), the concentration of the branched polyethyleneimine water solution is 0.1-5% by mass.

6. The method for rapidly detecting the sulfur dioxide residue in the sulfitation traditional Chinese medicine as claimed in claim 5, wherein branched polyethyleneimine with molecular weight of 10000 is adopted, and the mass percentage concentration of the branched polyethyleneimine water solution is 0.5%.

7. The method for rapidly detecting sulfur dioxide residue in Chinese medicine for sulfur fumigation as claimed in claim 1, wherein in step (2), said extract is H with a volume percentage concentration of 0.1% -20%₂SO₄Solution per 1g of sample4mL of the extract was added.

8. The method for rapidly detecting the sulfur dioxide residue in the sulfitation traditional Chinese medicine as claimed in claim 1, wherein in the step (2), the temperature of the headspace extraction is 30-90 ℃ and the extraction time is 5-30 min.

9. The method for rapidly detecting sulfur dioxide residue in a sulfitation traditional Chinese medicine according to claim 8, wherein the headspace extraction conditions are as follows: h with the volume percentage concentration of 5 percent is adopted₂SO₄The solution is used as extractive solution, and extracted at 75 deg.C for 15 min.

10. The method for rapidly detecting sulfur dioxide residue in a sulfitation traditional Chinese medicine according to claim 1, wherein the standard curve is drawn by the following method: na with a series of gradient concentrations₂SO₃Standard solution, SO in the same manner₂Headspace extraction and Raman detection at 612cm^-1To SO₂Characteristic Raman peak height and corresponding SO₂Linear regression of concentration values was performed.