GB/T 5009.103-2003 Determination of methamidophos and acephate pesticide residues in plant-derived foods

This standard specifies the method for the determination of methamidophos and acephate pesticide residues in cereals, vegetables and vegetable oils. This standard is applicable to the determination of methamidophos and acephate pesticide residues in cereals, vegetables and vegetable oils. GB/T 5009.103-2003 Determination of methamidophos and acephate pesticide residues in plant foods GB/T5009.103-2003 Standard download decompression password: www.bzxz.net

IS 67.040
National Standard of the People's Republic of China
GB/T 5009.103--2003
Replaces GB14876:1994
Determination of mctharnidophos and acephatepesticide residues in vegetable foods2003-08-11Published
Ministry of Health of the People's Republic of China
National Standardization Administration of China
Implemented on 2004-01-01
GB/T 5009.103—2003
This standard replaces CB14876—1504 Method for determination of methyl parathion and acetyl parathion pesticide residues in food>Compared with GR14875—1594, the main adjustments of this standard are as follows: The name of the standard has been changed, and the main name of the standard has been changed to Determination of methyl parathion and acetyl parathion pesticide residues in plant foods
According to GB/T2000L:4—2001 Standard Compilation Rules Part 4, Chemical Analysis Method 3, the conclusion of the original standard has been modified.
This standard was proposed by the Ministry of Health of the People's Republic of China and the units involved in this standard are: 1. Food Hygiene Supervision and Inspection Institute of the Ministry of Health, Jiangnan Agricultural University, and Shanghai Municipal Health Prevention and Control Station. The main drafters of this standard are Shen Zaihuan and Zhang Linxia. The original standard was first issued in 1994, and this standard is the first to be subscribed. 12
1 Specification
GB/15009.103—2003
Determination of the residual content of methylphosphonium and acetylmonophosphorus pesticides in plant foodsThis standard specifies the method for determining the residual content of methylphosphonium and acetylmonophosphorus pesticides in cereals, vegetables and plants. This standard is applicable to the residual content of methylphosphonium and acetylmonophosphorus in cereals, vegetables and plant oils. The test limits of this standard are 7.7910-\g and 2.79×10-g, 2 respectively. The sample containing organic phosphorus is burned in the presence of hydrogen and emits a characteristic light in the form of fragmentation: this characteristic light passes through the optical film, is collected by a photoelectric amplification tube, converted into an electrical signal, and recorded after being amplified by an electron microscope. The peak height of the test sample is compared with the peak height of the standard sample, and the corresponding content of the test sample is calculated. 3 Trial preparation
3. 1 Acetone,
3.2 Dioxane; weight.
3.3 Anhydrous acid.
3.4 ​​Activity; soak in 3mol/L sodium hydroxide overnight, wash with water until neutral, dry at 12 ℃ for use. 3.5 Methamidophus blue 9s%. 3.6 Micro-acetic acid (AE)
3.7 Medium-linked and acetic acid auxiliary standard: determine the amount of your home acetic acid standard, use two ketones to make 0.1mg/ml standard solution. When using, use acetone to prepare a single variety of standard solution according to the sensitivity of the instrument. Put it in a concentration box.
4 Receiver
4. Gas chromatograph, with flame photometer. 4.2 Electric alarm, etc.,
4.3 KE expansion device or rotary sensor,
4.4 Centrifuge
5 Preparation of test sample
Take the test grain and grind it into powder in a grinder. After passing through a 20-degree sieve, it is made into a content sample. Take the test sample and clean it economically, remove the inedible part and then put it into a crusher or a heat crusher to make the forbidden sample. 6 Analysis steps 6.1 Reagent and purification 8.1.1 Preparation: Take 10 g of the whole sample, accurately 100 μl, grind it into powder with anhydrous sodium thiourea (depending on the water content of vegetables), add 0.2 g-6.4 g of acetone (depending on the color content of vegetables) and 8 mL of acetone, filter for 0.1 h, and wait for gas analysis. 6.1.2 Weigh 10 g of the sample (except small amounts) accurately to 100 μl, put it into a stoppered bottle, add 40 μl of acetone, shake for 1 h, filter, concentrate and determine to 5 mL, and weigh for gas phase analysis. 13 GB/I 5009.103—2003
6.1.3 Wheat: Take a small amount of test sample 10 mL accurate to 0.001 g, add 0.2 g of charcoal and 4 mL of acetone in a cone, shake for 1 hour, filter, concentrate: make up to 5 mL, wait for gas chromatography analysis, 6.1.4 Vegetable oil: Mix the vegetable oil with 4 mL of acetone, add it several times into a 50 mL centrifuge tube, add 5ml water, centrifuge at 3000t/min for 5min. Collect the upper solution, add 10mL water and 10mL acetone to the lower oil chamber, centrifuge for 5min, absorb the upper solution, combine the two upper solutions, concentrate to near dryness with a K concentrator, add anhydrous sodium sulfate and water to grind into dry powder, put it into a cold conical flask, add 300mL activated carbon, 0mL dimethoate, add 0.51 pump: make up to 5ml 6.2 Chromatographic conditions 6.2.1 Chromatographic column: Inner diameter 3mm, diameter 0.5m, filled with 2%DEGS/Chromosorb WDMCS, 30-100cm 6.2.2 Gas washing gas, fresh air 7mL/min: air 1.7kg/cm2, fresh air 1.2kg/cm3 6.2.3 Temperature: Inlet 200℃, injection temperature 182℃ 6.3 Determination 6.3.1 Qualitative analysis: The retention time of the peak of methylamine and acetyl methylamine pesticide standard is called qualitative analysis. 6.3.2 Determination, external standard, standard samples of methyl methylamine and acetyl methylamine pesticide with known concentration are dissolved as external standards, and the temperature is controlled. 7 Calculation: According to the formula, the formula is: X -het.v.
h - V. n
X,——test sample concentration, in mg/kg (mg/kg) The content of organic matter in the component in the standard sample, in units of potential grams (E
,——test sample peak value, in millimeters (mm) Peak height of the component in the standard sample, in units of millimeters (mm); V——concentrated volume, in mL
V… The volume of the injected sample, in units of cut-off value (I).) The mass of the test sample, in grams (g)
8 PrecisionbzxZ.net
The absolute difference between the results of two independent determinations obtained under reproducible conditions shall not exceed 10% of the arithmetic mean, 1
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