GB/T 5009.184-2003 Determination of thiamethoxam residues in grains and vegetables

This standard specifies the method for determining the residues of thiothiazide in food. This standard is applicable to the determination of thiothiazide residues in grains and vegetables after spraying thiothiazide. GB/T 5009.184-2003 Determination of thiothiazide residues in grains and vegetables GB/T5009.184-2003 Standard download decompression password: www.bzxz.net

ICS67.040
National Standard of the People's Republic of China
GB/T5009.184—2003
Partially replaces GB14970--1994
Determination of buprofezin in cereals and vegetables2003-08-11Promulgated
Ministry of Health of the People's Republic of China
Standardization Administration of the People's Republic of China
2004-01-01Implementation
GB/T5009.184—2003
This standard replaces Chapter 3 to Chapter 5 of GB14970—1994 "Maximum Residue Limits of Buprofezin in Food". This standard is proposed and managed by the Ministry of Health of the People's Republic of China. This standard is drafted by Zhejiang Provincial Food Hygiene Supervision and Inspection Institute and Zhejiang Academy of Agricultural Sciences Plant Protection Institute. The main drafters of this standard are Wu Rong and Hu Lianying. 480
1 Scope
Determination of thiamethoxam residues in food and vegetables This standard specifies the method for determining thiamethoxam residues in food. This standard is applicable to the determination of thiamethoxam residues in food and vegetables after spraying thiamethoxam. 2 Reagents
The reagents used in this standard, if not specified, are of analytical grade (AR), and water is distilled water. 2.1 Acetone (re-distill before use).
2.2 n-Hexane (re-distill before use).
2.3 0.25 mol/L hydrochloric acid: Take 20.8 mL of hydrochloric acid and dilute to 1000 mL with water. GB/T5009.184—2003
2.4 1 mol/L sodium hydroxide solution: Weigh 40 g of sodium hydroxide, dissolve in water and dilute to 1000 mL. 2.5 Anhydrous sodium sulfate.
2.6 Buprofezin standard: purity ≥ 99.99%. 2.7 Buprofezin standard solution: accurately weigh 10 mg of buprofezin standard, dissolve it in 5 mL of acetone, and then dilute it to 100 mL with n-hexane to obtain a 1000 μg/mL standard stock solution. Dilute it with n-hexane to make a working solution before use. 3 Instruments
3.1 Gas chromatograph: with electron capture detector. 3.2 Electric oscillator.
3.3 Rotary evaporator.
4 Chromatographic analysis conditions
4.1 Chromatographic column: 5% 0V-17/Chromosorb W, 60 days and 80 months, column length 1 m, inner diameter 3 mm, glass column. 4.2 Temperature: column temperature 235°C; detector 270°C, vaporization chamber 270°C. 4.3 Carrier gas: high-purity nitrogen, 99.99% (1kg/cm2). 4.4 Reduction, 8.
5 Analysis steps
5.1 Weigh 20g of the crushed sample and place it in a 250mL stoppered conical flask, add 100mL of acetone, shake and extract on an electric shaker for 1h, and let it stand overnight.
5.2 Filter, put the filtrate into a round-bottom flask, rinse the residue with 60mL acetone and filter, combine the filtrates, concentrate on a rotary evaporator under reduced pressure to less than 5mL, then transfer the concentrate to a 250mL separatory funnel, wash the round-bottom flask twice with 10mL n-hexane, combine the washings into a separatory funnel, and then extract with 60mL 0.25mol/L hydrochloric acid three times, discard the n-hexane layer, add 16mL 1mol/L sodium hydroxide solution, and then extract with 60mL n-hexane three times, combine the extracts, dehydrate with 10g anhydrous sodium sulfate, and concentrate to dryness on a rotary evaporator at 40℃. Dissolve the residue with n-hexane and make up to 10mL5.3 Inject 1uL of the purified solution after making up to the volume according to the above-mentioned chromatographic conditions to obtain the peak height, check the value on the standard curve and calculate its content. 5.4 Drawing the standard curvebzxz.net
The standard stock solution was diluted with n-hexane to different concentrations of 0.10.5, 1.0, 1.5, 2.0, 2.5μg/mL standard working solution, 1μL was injected into the gas chromatograph, and the peak height was used as the ordinate and the standard amount was used as the abscissa to draw a graph to obtain the standard curve. 481
GB/T5009.184-2003
Result calculation
Where:
Ax1000
mx1000
-The content of thiazin in the sample, in milligrams per kilogram (mg/kg); X
A-The mass of thiazin in the injection volume, in micrograms (rg);-The injection volume (μL) is equivalent to the mass of the sample, in grams (g). m
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