阅读说明：本技术 一种基于便携式差分拉曼技术快速鉴别真假农药的方法 (method for rapidly identifying true and false pesticides based on portable differential Raman technology ) 是由 夏婧竹 刘峰 于爽 张苗苗 于 2019-10-14 设计创作，主要内容包括：本发明涉及一种基于便携式差分拉曼技术快速鉴别真假农药的方法,采用便携式差分拉曼系统,使用两种波长光源对样品进行检测,首先采集具有稳定微小波长差的双光源拉曼光谱仪检测到的两张市售农药拉曼光谱图数据,通过将两张拉曼光谱进行差分,并针对由于差分产生的拉曼特征信号进行特殊算法滤波,分离差分信号和基线偏差,得到消除了荧光等干扰的农药样品差分特征；最后,通过与农药标准样品谱图特征峰进行比对,可实现市售农药成分真假的鉴别。本发明采用双光源激发的差分技术,消除样品背景干扰,并通过对差分谱图进行特征滤波实现,准确提取样品更多细节拉曼特征。并针对这些差分拉曼特征建立市售农药的特征数据库和分类鉴别。由于使用了差分技术,大大提高了检测的准确性和灵敏度,实现了针对市售农药检测的便携拉曼系统,无需任何前处理过程即可完成,操作简单、检测速度快、准确度高,对农药质量安全的控制具有重大意义。(The invention relates to methods for rapidly identifying true and false pesticides based on portable differential Raman technology, which adopts a portable differential Raman system, uses two wavelength light sources to detect samples, firstly collects two pieces of Raman spectrogram data of commercially available pesticides detected by a double-light source Raman spectrometer with stable and tiny wavelength difference, differentiates the two Raman spectra, and filters the Raman characteristic signals generated by the difference by a special algorithm to separate the difference signals from baseline deviation to obtain the differential characteristics of the pesticide samples with eliminated interference of fluorescence and the like, and finally compares the differential characteristics with the spectrogram characteristic peaks of pesticide standard samples to realize the identification of true and false of commercially available pesticide components.)

1, method for rapidly identifying true and false pesticides based on portable differential Raman technology, which is characterized by comprising the following steps:

(1) establishing a Raman spectrum database of a pesticide standard substance: selecting various pesticide solid standard products, detecting by using a portable double-light-source Raman spectrometer to obtain two Raman spectrum characteristic parameters of each pesticide standard product, differentiating the two Raman spectra, filtering Raman characteristic signals generated by the difference, separating the differential signals from baseline deviation to obtain the Raman spectrum differential characteristics of the pesticide standard products, and establishing a Raman spectrum database of various pesticides;

(2) the pesticide sample to be detected does not need to be pretreated, and is directly detected according to the same detection system and spectrogram analysis algorithm in the step (1), so that a Raman spectrum difference data spectrogram of the commercially available pesticide sample with fluorescence interference eliminated is obtained;

(3) and comparing the Raman spectrum characteristic peak parameters after differential processing of the commercially available pesticide sample with a pesticide standard product Raman database established in software, and automatically identifying the authenticity of the commercially available pesticide components according to a matching rule built in instrument software.

2. The method for rapidly identifying true and false pesticides based on portable differential Raman technology as claimed in claim 1, wherein the portable dual light source Raman spectrometer can use light source with any wavelength, preferably 785nm, with wavelength difference range of 0.4-10 nm, preferably 1nm, single frequency output power less than or equal to 450mw, line width less than or equal to 0.06nm, spectrum range of 180-2800cm^-1And the Raman spectrum scanning time for collecting the sample is 3-50 seconds.

3. The differential filtering algorithm of claim 1, wherein the difference, alignment and baseline correction are performed simultaneously by means of iterative optimal solution based on the principle that an arbitrary function can be approximated to with arbitrary accuracy by a network of tri-level cells, and the algorithm separates the difference signal and the baseline deviation over tens of iterations (0.2 s in time).

4. The method for rapidly identifying true and false pesticides based on portable differential Raman technology, according to claim 1, wherein said pesticide standard can be kinds of herbicide, pesticide and bactericide.

5. The method for rapidly identifying true and false pesticides based on portable differential Raman technology, according to claim 1, wherein the formulation of the commercial pesticide sample can be water aqua, missible oil, soluble granules and wettable powder.

6. The method for rapidly identifying true and false pesticides of species based on portable differential Raman technology as claimed in claim 1, wherein in the method for processing the commercial pesticide sample of step (2), the pesticide with transparent and semitransparent outer package can be directly detected through a packaging bottle or a packaging bag without taking out the sample, and when the sample is opaque, part of the sample is taken out and directly measured.

7. The method for rapidly identifying true and false pesticides based on portable differential Raman technology according to claim 1, wherein the built-in matching rule in step (3) is that a Raman spectrogram library containing pesticide standard product characteristic peaks is placed in Raman spectrometer software, whether Raman signals match with standard product characteristic peaks in a Raman spectrogram of a commercially available pesticide sample is automatically identified, whether the commercially available pesticide contains pesticide components in the database is judged, the judgment rule is that the Raman shift deviation range of the characteristic peak signals compared with the standard product is less than or equal to +/-8 nm, and the matching proportion of the number of the characteristic peaks is greater than or equal to 40%.

Technical Field

The invention belongs to the field of analysis and detection of substances, and particularly relates to the technical field of rapid detection of product quality safety.

Background

In recent years, with the rapid development of social economy, people have higher and higher requirements on agricultural products, and in order to improve the output value of the agricultural products, high-toxicity pesticides are often used in agricultural production. However, the pesticide has great toxicity, so the use of the pesticide not only brings harm to soil, but also brings potential safety hazard to human health. In order to reduce the harm of highly toxic pesticides, the government of China increases the management of the use of the highly toxic pesticides, and part of the governments of pesticides forbid use, but part of manufacturers pursue profit and effect, add the highly toxic pesticides which are not marked on marks or are doped with 'recessive' components into the pesticides, and according to the regulation of the existing 'pesticide management regulations', the addition of other pesticide components without authorization is regarded as fake pesticides.

At present, the pesticide recessive component identification is realized by large-scale instruments, such as gas chromatography, liquid chromatography, mass spectrometry, infrared spectrometry and the like are common, although the methods have high accuracy and sensitivity, the detection time is long, the detection cost is high, a complex pretreatment process is required, only professional experiment technicians can operate the methods, the screening of a large number of samples cannot be realized, and the counterfeit requirement of the government supervision part cannot be met.

In recent years, the raman spectroscopy technology has been widely applied to in various industries such as food safety, biomedicine, molecular structure research, biochemistry, archaeology and cultural relic identification, public security and legal sample analysis, anti-terrorism technology and the like, and the raman spectroscopy technology called molecular fingerprint has been greatly advocated in the field of optical rapid inspection due to its excellent characteristics of no damage, convenience, high speed and high stability.

The method includes collecting two different spectra in two slightly shifted excitation wavelengths, exciting light (fluorescence or phosphorescence) from the lowest state of multiple states of , so that background (stimulated emission spectrum) is not affected by small shift of the excitation light, and noise and environmental interference light are not related to incident wavelength of a light source, wherein the position of a Raman spectrum appearing as a characteristic peak of a scattering spectrum is in a fixed relation with the position of an excitation light source spectrum, and the Raman characteristic peak moves when the excitation light frequency moves.

At present, a method for restoring a differential spectrum by using a deconvolution algorithm is used, but the algorithm is time-consuming, introduces a plurality of hypotheses, has a good spectrogram restoring effect only on pure substances (approximate standard substances), has poor restoring accuracy on samples which actually have matrix interference, and is difficult to be applied to accurate determination of complex matrix samples.

Disclosure of Invention

In order to solve the technical problems, the invention provides methods for rapidly identifying true and false pesticides based on a portable differential Raman technology, and the method can be used for identifying recessive components of pesticides.

The invention relates to a method for rapidly identifying true and false pesticides based on a portable differential Raman technology, which comprises the following steps of (1) establishing a Raman spectrum database of pesticide standard products, selecting various types of pesticide solid standard products, detecting by using a portable dual-light-source Raman spectrometer to obtain two Raman spectrum characteristic parameters of each pesticide standard product, differentiating the two Raman spectra, filtering Raman characteristic signals generated by the difference, separating the differential signals from a base line to obtain Raman spectrum differential characteristics of the pesticide standard products, establishing a Raman spectrum database of various pesticides, and (2) directly detecting the pesticide sample to be detected without pretreatment according to the same detection system and spectrum analysis algorithm in the step (1) to obtain a Raman spectrum differential data spectrum of the commercially available pesticide sample without fluorescence interference, and (3) comparing the Raman spectrum characteristic peak parameters after differential processing of the commercially available pesticide sample with the established Raman spectrum database of the pesticide standard products in software, and automatically identifying the commercially available pesticide components based on matching rules built in the software.

, the portable double-light-source Raman spectrometer can adopt a light source with any wavelength, preferably 785nm, with a wavelength difference range of 0.4-10 nm, preferably 1nm, a single-frequency output power of less than or equal to 450mw, a line width of less than or equal to 0.06nm, and a spectrum range of 180-^-1And the Raman spectrum scanning time for collecting the sample is 3-50 seconds.

, the difference filtering algorithm is based on the principle that any function can be approximated to by a network with three-layer units with any precision, and the difference, alignment and baseline correction are completed simultaneously in an iterative optimal solution mode, and the algorithm can accurately separate difference signals and baseline deviation after dozens of iterations (time spent 0.2 s) to obtain accurately restored difference spectrogram data.

, the pesticide standard can be kinds of herbicide, pesticide and bactericide.

Further , the formulation of the commercial pesticide sample can be water solution, emulsifiable solution, soluble granules and wettable powder.

, in the method for processing the pesticide sample on the market in the step (2), the pesticide with transparent and semitransparent outer package can be directly detected through a packaging bottle or a packaging bag without taking out the sample, and when the sample is opaque, part of the sample is taken out and directly measured.

, the built-in matching rule in the step (3) is that a Raman spectrogram library containing characteristic peaks of pesticide standard samples is placed in Raman spectrometer software, whether Raman signals in the Raman spectrogram of a commercially available pesticide sample are matched with the characteristic peaks of the standard samples or not is automatically identified, whether the commercially available pesticide contains pesticide components in the database or not is judged, and the judgment rule is that the Raman shift deviation range of the characteristic peak signals is less than or equal to +/-8 nm compared with the standard samples, and the quantity matching proportion of the characteristic peaks is more than or equal to 40%.

The invention has the beneficial effects that: (1) the displacement differential Raman spectrometer has the advantages that the displacement differential Raman is miniaturized and portable, the accuracy and the sensitivity of a portable differential system are greatly improved through a differential and signal filtering technology, the direct detection of high-fluorescence and complex-matrix commercially available pesticides can be realized, the problem that Raman is difficult to detect high-fluorescence samples and complex-matrix samples is solved, meanwhile, the automatic discrimination of Raman differential characteristic signals is realized, the problems of commercially available pesticide matrix impurities, environmental light peaks and PL peak interference peaks are effectively filtered, and an innovative nondestructive detection means is provided for the rapid detection of commercially available pesticides.

(2) The method has the advantages of no need of pretreatment, avoidance of harm and pollution of pesticides and pretreatment reagents, simplicity, easiness in operation and suitability for field detection of no professional background personnel.

(3) The method has the advantages of low detection limit, high accuracy, good universality, suitability for detection of most types of pesticide commodities on the market and strong practicability.

(4) The detection time is less than 30 seconds, the detection is convenient and quick, other reagent consumables are not needed, and the cost is saved.

Drawings

FIG. 1: raman spectrogram of brand A diquat pesticide and paraquat standard product.

FIG. 2: and a Raman spectrogram of brand B of the diquat pesticide and a diquat standard product.

FIG. 3: and (3) a Raman spectrogram obtained by different differential algorithms of brand A diquat pesticide.

FIG. 4: raman spectra of a commercial pesticide triadimefon and a standard triadimefon.

FIG. 5: raman spectra of commercially available pesticides with different amounts of diquat.

Detailed Description

The present invention is further illustrated in the following detailed description of specific examples.