This standard specifies the method for determining the amount of diazinon residues in cereals, vegetables and fruits. This standard is applicable to the determination of residues in cereals, vegetables, fruits and other plant foods that have been treated with diazinon pesticide formulations. The detection limit of this standard is 0.01 mg/kg. GB/T 5009.107-2003 Determination of diazinon residues in plant foods GB/T5009.107-2003 Standard download decompression password: www.bzxz.net

ICS67.040
National Standard of the People's Republic of China
GB/T5009.107—2003
Replaces GB/T14929.1-1994
Determination of diazinon residues in vegetable foodsPromulgated on August 11, 2003
Ministry of Health of the People's Republic of China
Standardization Administration of the People's Republic of China
Implementation on January 1, 2004
GB/T5009.107-2003
This standard replaces GB/T14929.1—1994 "Method for determination of diazinon residues in foods". Compared with GB/T14929.1-1994, this standard has been modified as follows: The Chinese name of the standard has been modified, and the Chinese name of the standard has been changed to "Determination of Diazinon Residues in Plant Foods": - The structure of the original standard has been modified according to GB/T20001.4-2001 "Standard Preparation Rules Part 4: Chemical Analysis Methods".
This standard is proposed and managed by the Ministry of Health of the People's Republic of China. The drafting units of this standard are: Analysis and Testing Center of Chinese Academy of Agricultural Sciences, Institute of Plant Protection of Guangdong Academy of Agricultural Sciences, Shenyang Chemical Research Institute, and Food Hygiene Supervision and Inspection Institute of the Ministry of Health. The main drafters of this standard are: Zhang Qiao, Zhang Yousong, Gao Chengren, and Zhang Linzhi. The original standard was first issued in 1994, and this is the first revision. 32bzxz.net
1 Scope
Determination of Diazinon Residues in Plant Foods This standard specifies the method for determining the diazinon residues in cereals, vegetables and fruits. GB/T5009.107—2003
This standard is applicable to the determination of residues in cereals, vegetables, fruits and other plant foods that have been treated with diazinon pesticides. The detection limit of this standard is 0.01tng/kg. 2 Principle
The sample containing organic phosphorus burns on a hydrogen-rich flame and emits characteristic light with a wavelength of 526nm in the form of hydrogen, phosphorus and oxygen fragments. This characteristic light is selected by a filter, received by a photomultiplier tube, converted into an electrical signal, amplified by a micro-current amplifier, and recorded. The peak height of the sample is compared with the peak height of the standard to calculate the equivalent content of the sample. 3 Reagents
3.1 Acetone.
3.2 Anhydrous sodium sulfate.
3.3 Dichloromethane.
3.4 ​​Sodium chloride.
3.5 Diazinon standard. 3.6 Preparation of diazinon standard solution: Prepare a 1 mg/mL standard stock solution with hexane and store it in a 4°C refrigerator. When using, dilute it with hexane to a 1 pg/mL standard working solution.
4 Instruments
4.1 Pulverizer.
4.2 Tissue crusher.
4.3 Rotary evaporator.
4.4 Gas chromatograph with FPD.
5 Analysis steps
5.1 Sample extraction
5.1.1 Cereals
5.1.1.1 Rice: Weigh 5g (accurate to 0.001g) of brown rice that has been crushed through a 40-mesh sieve into a 50mL stoppered conical flask, add 10mL of acetone, shake for 30rmin, and place overnight. No purification is required for testing. 5.t.1.2 Wheat and corn: Weigh 10g (accurate to 0.001g) of wheat and corn that has been crushed through a 40-mesh sieve into a 100mL stoppered conical flask, add 30mL of acetone, shake for 30min, place overnight, filter through filter paper containing anhydrous sodium sulfate, take 15mL of the filtrate (about 5g of sample) and concentrate to 2mL. Make up to volume for testing.
5.1.2 Fruits and vegetables: Weigh 50g (edible part) of the sample (accurate to 0.001g), place in a tissue crusher, add 100mL acetone, crush and extract for 1min~2min, filter, wash with acetone, combine the filtrate and washing liquid and transfer to a 500mL separatory funnel. 5.2 Purification
Add sodium azide to the filtrate in 5.1.2 to make it supersaturated, shake vigorously for 2min~3min, and let it stand for 10min to allow acetone to salt out from the aqueous phase. The aqueous phase was then shaken and extracted with 50 mL of dichloromethane for 2 min, and the layers were allowed to stand for separation. The acetone and difluoromethane extracts were combined, dehydrated through a 20g~30g anhydrous sodium sulfate glass funnel and filtered into a 250 mL round-bottom flask. The container and anhydrous sodium sulfate were then washed with about 40 mL of dichloromethane, and the washings were combined with the extracts, concentrated under reduced pressure to 2 mL, and fixed to volume for testing. 5.3 Gas chromatography determination
5.3.1 Chromatographic conditions
5.3.1.1 Chromatographic column 1.3 mm (inner diameter) × 1.5 m glass column, filled with 2.3% 0V-17 + 3% 0V-210/Chromosorb W (AW-DMCS) 80100 mesh.
Temperature: column temperature 200°C, injection port and detector 230°C. Flow rate: carrier gas (nitrogen) 100mL/min, air 50mL/min, hydrogen 100mL/min. Retention time 2min16s.
5.3.1.2 Chromatographic column 2: 3mm (inner diameter) × 1.5m glass column, filled with 5% SE-30/ChromosorhW ​​(AW-DWCS). 80 days to 100 days.
Temperature: column temperature 200℃, injection port 220℃, detector 265℃. Flow rate: carrier gas (nitrogen) 60mL/min, air 50mL/min, hydrogen 80mL/min. Retention time 2min5s.
6 Determination
Pipette 2~5μL of standard solutions of various concentrations and inject them into the gas chromatograph respectively. The peak heights of diazinon of different concentrations can be measured and a diazinon standard curve can be drawn. At the same time, take 2μL~5μL of the sample solution and inject it into the gas chromatograph. The measured peak heights can be used to find the corresponding content from the standard curve.
7 Result calculation
Calculate according to the following formula:
Where:
X-the content of diazinon in the sample, in milligrams per kilogram (mg/kg); A-the content of diazinon in the injection volume (checked from the standard curve), in nanograms (ng); V-the volume of the sample extract concentrated to a fixed volume, in milliliters (mL); V,-the sample injection volume, in microliters (μL); m
The mass of the sample, in grams (g).
The calculation result retains two significant figures.
8 Precision
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 20% of the arithmetic mean34
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