Surface enhanced Raman scattering rapid screening method for methamidophos in vegetable

A surface-enhanced Raman and methamidophos technology, which is applied in Raman scattering, material excitation analysis, etc., can solve problems such as undiscovered methamidophos Raman research reports, and achieve simple operation, low detection limit, fast and accurate qualitative Effect

Inactive Publication Date: 2012-01-11
JIANGNAN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

At present, no Raman research reports r

Method used

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  • Surface enhanced Raman scattering rapid screening method for methamidophos in vegetable
  • Surface enhanced Raman scattering rapid screening method for methamidophos in vegetable
  • Surface enhanced Raman scattering rapid screening method for methamidophos in vegetable

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Accurately weigh 50 mg of methamidophos, and dilute to 50 mL with acetone to prepare a standard stock solution with a concentration of 1000 μg / mL.

[0018] Dilute successively to standard solutions with concentrations of 500 μg / mL, 100 μg / mL, 10 μg / mL, 1 μg / mL, 0.1 μg / mL, 0.01 μg / mL, and 0.001 μg / mL. with HNO 3 Adjust the pH to 2.3, select a Raman spectrometer with a laser wavelength of 785nm, set the laser power to 250mw, and scan each sample for 10s to obtain the SERS spectra of different concentrations of methamidophos. Taking the concentration of methamidophos as the abscissa, 668cm in the SERS spectrum -1 The peak height of the vibration peak is drawn as the ordinate to draw the standard curve ( image 3 ), the standard curve function relationship is: y=59.552x+3856.3, correlation coefficient r=0.9852, good linearity, and can be used to determine the amount of analyte in the sample.

Embodiment 2

[0020] Take the experimental sample of Chinese cabbage, wash it, dry it, remove the non-edible part, chop it or mash it with a tissue masher to make a vegetable sample.

[0021] Weigh 10g of vegetable sample, accurate to 0.001g, grind it into dry powder with 60g of anhydrous sodium sulfate, pour it into a stoppered Erlenmeyer flask, add 0.3g of activated carbon and 80ml of acetone, shake for 0.5h, suction filter, and the filtrate Concentrate to 5mL, and pass through a 0.45μm filter membrane for Raman detection. Six parallel runs were made for each vegetable sample, and the analysis results are shown in Table 1.

[0022] Table 1 Determination results of methamidophos in Chinese cabbage

[0023]

Embodiment 3

[0025] Add different amounts of methamidophos standard solution in the hairy cabbage sample of known methamidophos content, operate by the step in example 2, each sample is repeatedly measured 6 times, measure the standard addition recovery rate and relative standard deviation simultaneously, The results are shown in Table 3. The recovery rate of the standard addition was between 86.73% and 96.61%, and the relative standard deviation was between 1.16% and 2.51%. The method was reliable.

[0026] Table 3SERS method detects the recovery rate of methamidophos

[0027]

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PUM

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Abstract

The invention belongs to the field of rapid screening method for methamidophos in vegetables. The method comprises steps of: crushing a vegetable sample, mixing and oscillating with a polar solvent, and carrying out pumping filtration to obtain a filtrate; concentrating to dry, carrying out a constant volume with ultrapure water, and filtering with a 0.045 mum membrane; preparing a nano silver solution by a citrate reduction method; mixing the vegetable extract and the nano silver solution, adjusting a pH to 1.0-5.0, and detecting methamidophos in the sample by a Raman spectrometer; selecting a Raman spectrometer with 785 nm laser wavelength, setting a laser power to 50-300 mw, a scan time of 2-20s, mixing the methamidophos ultrapure water solution and the prepared nano silver solution in a certain ration, and carrying out a laser scan detection; and drafting a standard curve with a methamidophos concentration as an abscissa and a characteristic peak height as an ordinate, so as to analyze methamidophos content in the sample. The invention provides a low detection limit and simply operated Raman detection method, which can rapidly and accurately carry out qualitative and quantitative detection of methamidophos in the vegetable sample and can be used for on-site large scale sample rapid screening.

Description

technical field [0001] The invention belongs to the field of rapid screening methods for methamidophos residues in vegetables, in particular to a surface-enhanced Raman spectrum rapid screening method for methamidophos. Background technique [0002] Methamidophos is a high-efficiency, broad-spectrum organophosphorus insecticide and acaricide. It used to be the largest pesticide produced and used in my country. Although the country banned its sale and use in 2007, the phenomenon of violations Repeated prohibition continues, methamidophos residues exceed the standard and food poisoning incidents occur from time to time, making the detection of methamidophos residues a focus of attention. [0003] The current detection methods mainly include gas chromatography (GC) or gas chromatography / mass spectrometry (GC / MS), liquid chromatography / mass spectrometry (HPLC / MS), enzyme-linked immunoassay, sensor detection and so on. The first two methods are time-consuming and costly, while th...

Claims

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Application Information

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IPC IPC(8): G01N21/65
Inventor 姚卫蓉季培周孙莹莹
Owner JIANGNAN UNIV
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