阅读说明：本技术 一种基于增强拉曼散射相对强度外标法的痕量物质定量分析方法 (Quantitative analysis method for trace substance based on enhanced Raman scattering relative intensity external standard method ) 是由 张政军 赵丰通 于 2019-11-26 设计创作，主要内容包括：本发明涉及一种基于表面增强拉曼散射技术的痕量物质定量分析方法,属于痕量有机物定量分析技术领域。所述方法采用混合物体系中表面增强拉曼谱线相对强度的外标方法来实现对液体环境中痕量有机物的定量分析；通过常规的贵金属基表面增强拉曼散射基片实现对混合物的图谱测量,并采用不同物质在谱线中的相对拉曼散射强度信息建立外标工作曲线,实现对痕量物质含量的定量分析和浓度的定量分析。本发明充分利用了表面增强拉曼散射技术对痕量物质检测的优势,便捷地实现对液体中痕量物质的定量分析,在水体痕量污染物检测、生物标志物检测、食品微量添加剂等物质的检测中有广阔的应用前景。(The invention relates to a trace substance quantitative analysis method based on a surface enhanced Raman scattering technology, and belongs to the technical field of trace organic matter quantitative analysis. The method adopts an external standard method of surface enhanced Raman spectrum relative intensity in a mixture system to realize quantitative analysis of trace organic matters in a liquid environment; the method realizes spectrum measurement of a mixture through a conventional noble metal-based surface enhanced Raman scattering substrate, and establishes an external standard working curve by adopting relative Raman scattering intensity information of different substances in a spectral line, thereby realizing quantitative analysis of the content and concentration of trace substances. The method fully utilizes the advantages of the surface enhanced Raman scattering technology for detecting the trace substances, conveniently realizes the quantitative analysis of the trace substances in the liquid, and has wide application prospect in the detection of the trace pollutants in the water body, the detection of the biomarkers, the detection of trace additives in food and other substances.)

1. A trace substance quantitative analysis method based on an enhanced Raman scattering relative intensity external standard method is characterized by comprising the following steps:

1) obtaining a surface enhanced Raman scattering spectrum for the object to be detected by using a surface enhanced Raman scattering effect substrate;

2) establishing an external standard working curve of relative content and relative Raman scattering intensity among different substances;

3) quantitative analysis of the relative content of each substance in the system to be detected is realized by utilizing an external standard working curve;

4) the quantitative analysis of the actual concentration of the substance to be detected is realized by adding a substance with a known concentration.

2. The analysis method according to claim 1, wherein the relative raman scattering intensity of different substances in the analyte is solved in step 1) by using a peak separation method or a regression method.

3. The analysis method according to claim 1, wherein the quantitative analysis of the content of each substance in the analyte is realized in step 3) by using the relative raman scattering intensity information of different substances in the surface enhanced raman scattering spectrum of the mixed system.

4. The analytical method according to claim 1, wherein the predicted value of the actual concentration of the analyte is obtained in step 4) by adding a substance with a known concentration and then directly calculating the content by combining with the quantitative analysis of the content performed in step 3).

5. The assay method according to claim 2, wherein S is used for the n-membered mixture system _tolObtaining the relative enhanced Raman scattering intensity information of each component by means of peak separation or regression and the like, wherein a is shown as a formula (1) _iIs the spectrum S of the ith element relative to the selected pure substance _iCoefficient (c):

then, an external standard working curve represented by the formula (2) is established for any two components, wherein x _iAnd x _jAre the contents corresponding to the i and j components.

The relative content of each substance in the substance to be detected can be analyzed through the relation, and the formula (3) is shown as follows:

for the detection of the concentration, if the known substance x is added _iHas a concentration of c _iThen pass throughAnd (4) obtaining the concentration of the substance to be detected as follows:

Technical Field

The invention belongs to the technical field of quantitative analysis of trace organic matters, and particularly relates to a method for realizing quantitative analysis of trace substances based on an external standard method for enhancing relative Raman scattering intensity of different substances in a Raman spectrum line.

Background

The Surface Enhanced Raman Scattering (SERS) spectrum becomes an important spectrum analysis method, plays an important role in various fields, can realize trace detection of substances such as environmental pollutants, biomarkers and food additives, and has the advantages of high sensitivity, rapidness, no damage, simple sample preparation and the like. At present, the surface enhanced Raman scattering substrate designed based on noble metals (silver, gold and copper) is successful, plays an important role in the field of trace substance detection, and particularly further expands the application range of the flexible substrate and the like. However, semi-quantitative and quantitative analysis of trace substances based on surface enhanced raman scattering spectroscopy still faces many problems, and working curves based on absolute raman scattering intensity and substance concentration often affect actual analysis due to uniformity of the substrate itself and batch-to-batch variability of the substrate. Principal Component Analysis (PCA), nonlinear clustering algorithm and the like are also required to be further promoted due to the complex data preprocessing, large model training data quantity, poor anti-interference and robustness of the model, insufficient intuition and the like.

As an inelastic scattering spectrum technology, the Raman scattering intensity of a substance is far smaller than that of elastic scattering, the application range of the surface enhanced Raman scattering technology is greatly expanded due to the development of the surface enhanced Raman scattering technology, but the application of an absolute Raman scattering intensity-concentration working curve is limited due to the factors such as the uniformity and the stability of a surface enhanced Raman scattering substrate. The relative intensity external standard method is successfully applied to diffraction analysis, and the relative intensity information of different phases can be used for quantitatively analyzing the phase content. Similarly, in the raman spectrum, the relative intensity information of different substances also includes the information of the relative content thereof, and the relative intensity information can effectively reduce the influence of absolute intensity change caused by the uniformity and stability of the substrate on quantitative analysis. The relative intensity external standard method can be used for accurately analyzing the content in the mixture, and substances with known concentrations can be added for quantitatively analyzing the concentration of the substance to be detected. In practical application, the method is very important for analyzing the relative content of substances, and the quantitative analysis method based on the enhanced Raman spectrum relative intensity external standard method has wide application prospects in the aspects of analysis of the content of environmental pollutants, biological metabolites, food additives and the like.

Disclosure of Invention

The invention aims to provide a method for realizing quantitative analysis of material content and concentration based on relative Raman scattering intensity information of different materials in a surface enhanced Raman spectrum, which mainly adopts an external standard method of relative intensity and relative content to realize the quantitative analysis of the material content and the concentration.

In order to achieve the purpose of the invention, the adopted technical scheme is as follows:

a trace substance quantitative analysis method based on an enhanced Raman scattering relative intensity external standard method is characterized by comprising the following steps:

1) obtaining a surface enhanced Raman scattering spectrum for the object to be detected by using a surface enhanced Raman scattering effect substrate;

2) establishing an external standard working curve of relative content and relative Raman scattering intensity among different substances;

3) quantitative analysis of the relative content of each substance in the object to be detected is realized by utilizing an external standard working curve;

4) the quantitative analysis of the actual concentration of the substance to be detected is realized by adding a substance with a known concentration.

Further, in the step 1), the relative Raman scattering intensity of different substances in the object to be detected is solved by adopting methods such as peak separation or regression and the like.

Further, in the step 3), the content of each substance in the object to be detected is quantitatively analyzed by using the relative Raman scattering intensity information of different substances in the surface enhanced Raman scattering spectrum of the mixed system.

Further, in the step 4), another substance with known concentration is added, and then the content quantitative analysis realized in the step 3) is combined for direct calculation, so that the predicted value of the actual concentration of the substance to be detected is obtained.

Specifically, the analysis method firstly uses a surface enhanced Raman scattering effect substrate to obtain a surface enhanced Raman scattering spectrum for a substance to be detected, secondly establishes an external standard working curve of relative content and relative Raman scattering intensity among different substances, realizes analysis of the relative content of the trace substance in the mixture based on the external standard working curve, and can obtain the actual concentration of the substance to be detected by adding the substance with known concentration for concentration analysis and then according to the external standard working curve. The quantitative analysis is carried out by utilizing the information of the relative intensity, so that the interference of the self uniformity and the batch-to-batch difference of the surface enhanced Raman scattering substrate on the quantitative analysis can be effectively avoided.

The relative Raman scattering intensity external standard working method is established based on the surface enhanced Raman scattering spectrum of the mixture, the relative Raman scattering intensity can be determined by adopting a data processing mode through methods such as peak separation or regression, and the actual concentration of the substance to be measured can be predicted according to an external standard working curve by adding another substance with known concentration.

The method does not limit the used surface-enhanced Raman scattering effect substrate, the surface-enhanced Raman scattering effect substrate aims to realize the acquisition of the Raman spectrum of the trace substance, an external standard method based on the relative intensity of the surface-enhanced Raman scattering does not depend on the type of the substrate, and meanwhile, the interference of the uniformity of the substrate and the difference among batches on the quantitative analysis result can be effectively avoided.

The trace substance quantitative analysis based on the surface enhanced Raman scattering relative intensity external standard method is implemented as follows: solving the relative Raman scattering intensity of different substances in the surface enhanced Raman scattering spectral line of the mixture system by means of peak separation or regression and the like, and then establishing an external standard working curve of the relative Raman scattering intensity and the relative content; further, quantitative analysis on the relative content of each substance component in the substance to be detected can be realized through an external standard working curve; furthermore, the quantitative analysis of the trace substances can be realized by adding the substances with known concentrations as the concomitants of the substances to be detected, determining the relative contents of the additives and the unknown substances in the mixture spectrum according to an external standard working curve, and then obtaining the concentration predicted value of the substances to be detected according to the known concentrations of the additives. The specific operation of data processing is as follows: for n-membered mixture systems S _tolThe relative surface Raman scattering intensity information of each member can be obtained by a method of peak separation or regression and the like, as shown in formula (1), wherein a _iIs the spectrum S of the ith element relative to the selected pure substance _iCoefficient (c):

then, for any two components, an external standard working curve represented by the formula (2) can be established, wherein x _iAnd x _jAre the contents corresponding to the i-th and j-th components.

The relative content of each substance of the system to be detected can be analyzed through the relation, and the formula (3) is as follows:

for the detection of the concentration, if the known substance x is added _iHas a concentration of c _iThen, the concentration of the substance to be measured can be obtained by the following formula (4):

the method has the advantages that the quantitative analysis of the content and concentration of the substances in the mixture system is carried out by a relative surface enhanced Raman scattering intensity external standard method, the interference of the self uniformity of the surface enhanced Raman scattering substrate and the difference among batches on the quantitative analysis can be effectively weakened, the surface enhanced Raman scattering technology can play a greater role in the quantitative analysis of the trace substances, and the advantages of convenience and rapidness, simple sample preparation, high detection sensitivity and the like of the surface enhanced Raman scattering technology can be fully played in the quantitative analysis. The method has wide application prospect in environmental pollutant detection, biomarker detection and food additive detection.

Drawings

Fig. 1(a) is a surface-enhanced raman scattering spectrogram of each of a pure substance, a known modeling mixed system, and a system to be quantitatively analyzed.

FIG. 1(b) is an external standard working curve established from the modeled mixed system versus Raman scattering intensity.

FIG. 2(a) is a plot of the relative surface enhanced Raman scattering intensity of the system 1 to be quantified in example 1 plotted in an external standard working curve.

FIG. 2(b) is a diagram showing the quantitative prediction of the 4-MPY content in the system to be quantitatively analyzed 1 in example 1.

FIG. 3(a) is a graph showing the position of the system to be quantitatively analyzed 2 in example 2 in an external standard working curve.

FIG. 3(b) is a graph showing the prediction of the 4-MPY content in the system to be quantitatively analyzed 2 in example 2.

FIG. 4 is a diagram illustrating the prediction of the 4-MPY in the system 2 in example 3.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings and examples. The following examples are illustrative and not intended to be limiting, and are not intended to limit the scope of the invention.

According to the invention, the surface enhanced Raman scattering substrate is adopted to obtain the surface enhanced Raman scattering spectrum of the mixture system, then the spectrum of the mixture system is subjected to peak separation or regression and other treatments, an external standard working curve of relative surface enhanced Raman scattering intensity and relative content among different substances is established, the actual content and concentration of the substance to be detected can be quantitatively analyzed according to the external standard working curve, the interference of factors such as substrate uniformity and the like on quantitative analysis can be effectively avoided, and the quantitative analysis of the substance to be detected can be conveniently realized.

FIG. 1(a) is a mixture system for carrying out an example comprising tetra-mercaptopyridine (4-MPY) and tetra-mercaptobenzoic acid (4-MBA) and a mixture system for establishing relative surface enhanced Raman scattering intensity versus relative content: a mixed system containing 20% 4-MPY and 80% 4-MBA and a system containing 67% 4-MPY and 33% 4-MBA. And two systems to be quantitatively analyzed, wherein the surface enhanced Raman scattering spectrograms of the systems are shown in FIG. 1 (a). FIG. 1(b) shows 4-MPY (1096 cm) in two known mixed samples ^-1) And 4-MBA (1074 cm) ^-1) And an external standard working curve established relative to the Raman scattering intensity, wherein the function curve is obtained by fitting a straight line passing through the origin.

Fig. 2(a) shows the position of the relative surface-enhanced raman scattering intensity of the quantitative analysis system 1 in example 1 in the external standard working curve, the actual solution relative content is 1:2, and corresponds to the position of 0.5 on the abscissa, and it can be seen in the figure that the experimental value is also substantially on the external standard working curve, thus it is illustrated that the external standard working curve can accurately predict the substance content thereof, and the relative content range of the substance in the mixture to be measured is directly calculated according to the external standard working curve, so as to obtain the predicted 4-MPY content in fig. 2(b), and in fig. 2(b), y ═ x is a theoretical curve in which the predicted 4-MPY content is completely consistent with the actual content, so that it can be seen that the predicted 4-MPY content is substantially consistent with the actual content.

FIG. 3(a) shows the position of the sample system 2 to be quantitatively analyzed in example 2 in the external standard working curve, and it can be seen that the data points are slightly shifted from the external standard working curve, the 4-MPY content predicted by the external standard working curve is shown in FIG. 3(b), and the predicted 4-MPY content value is slightly higher than the true value, but within the error tolerance range.

FIG. 4 is a result of predicting the actual concentration of 4-MPY in the system 2 to be quantitatively analyzed in example 3, in order to predict the concentration of 4-MPY in example 2, 4-MBA with a known concentration of 5 μ M is added, a relative content ratio range of the two is obtained according to the relative surface enhanced Raman scattering intensity prediction in example 2(a), a curve cluster of the concentrations of the two is drawn by using the ratio range as a slope, and the predicted concentration of 4-MPY is predicted to be 5.02 to 5.07 μ M, which is slightly higher than the true concentration of 4-MPY of 5 μ M but within an error allowable range according to the intersection range of the known concentration of 4-MBA and the curve bundle.

The feasibility and effectiveness of using external standard working curves of relative surface enhanced raman scattering intensity and relative content for quantitative analysis of actual substances is illustrated below in conjunction with three examples.