This standard specifies the gas chromatography determination method for the residual 2,4-D butyl ester in grains. This standard is applicable to the determination of the residual 2,4-D butyl ester in grains. The minimum detection amount of this standard is 0.01ng; the linear range is 0.01ng～10ng. GB/T 5009.165-2003 Determination of the residual 2,4-D butyl ester in grains GB/T5009.165-2003 Standard download decompression password: www.bzxz.net

ICS67.040
National Standard of the People's Republic of China
GB/T5009.165—2003
Determination of 2,4-D butylate residues in grains2003-08-11Issued
Ministry of Health of the People's Republic of China
National Standardization Administration of China
2004-01-01Implementation
This standard is proposed and managed by the Ministry of Health of the People's Republic of China.
The responsible drafting units of this standard are: Beijing Municipal Health and Epidemic Prevention Station and Food Hygiene Supervision and Inspection Institute of the Ministry of Health. The main drafters of this standard are: Zhao Liwen, Kang Junxing, Zhang Ying. This is the first time the original standard is released.
GB/T5009.165-2003bzxZ.net
GB/T5009.165—2003
2,4-D butylate is a hydroxyethyl amine hormone-type selective herbicide and plant growth regulator. According to my country's pesticide toxicity classification standard, it is a low-toxic pesticide and has been registered on my country's grain crops. my country has established a residue limit of 0.25mg/kg for 2,4-D butylate in grain. This standard provides a method for determining the residue of 24-D butylate in grain.
1 Range
Determination of 2,4-D butylate residue in grain
This standard specifies the gas chromatography determination method for the residue of 2,4-D butylate in grain. This standard is applicable to the determination of the residue of 2,4-D butylate in grain. The minimum detection amount of this standard is 0.01ng and the linear range is 0.01ng～10ng. 2 Principle
GB/T5009.165—2003
2,4-D butyl ester in the sample is extracted with an organic solvent, and the interfering substances are removed by liquid-liquid distribution and column purification. The gas chromatography electron capture detector is used for determination. The qualitative analysis is based on the retention time of the chromatographic peak and the quantitative analysis is based on the peak area of ​​the external standard method. 3 Reagents
Unless otherwise specified, only reagents determined to be analytically pure and distilled water or water of equivalent purity are used in the analysis. 3.1 Petroleum aldehyde: 30℃60℃, re-distilled filling. 3.2 Acetone.
Sodium chloride.
Anhydrous sodium sulfate, calcined at 650℃ for 4h, stored in a desiccator. 3.5
Eluent: petroleum ether + acetone (95+5). 3.6 2,4-D butylate standard solution: Prepare 2,4-D butylate (2,4-Dbutylate 99.9%) with petroleum ether to a 1.00 mg/mL solution. Instruments
Gas chromatograph with electron capture detector. 4.2
Chromatographic column: 1.7% ov-17 and 2% QF-1 mixed stationary phase. Carrier: chromorsorb, 2m×3.2mm(id). 4.3
Oscillator.
Stopped Erlenmeyer flask: 100ml.
Filter: Glass sand core funnel (G3, 25mL). 4.5
Separating slide: 150mL.
Glass syringe: 10mL.
Pulverizer.
4.9pt-Silica-magnesium adsorbent chromatography pretreatment column, filled with 0.4g 60-80 mesh silica-magnesium adsorbent. 5 Analysis steps
5.1 Extraction
Crush the sample through a 20-mesh sieve and mix well. Weigh 20g of the sample, place it in a conical flask, add 50mL of petroleum ether, oscillate on an oscillator for 20 minutes, let it stand and separate, take the upper layer of solution and filter it with a glass sand core funnel. 5.2 Purification
Put the extract in a funnel containing 50mL of 50g/L sodium nitride (NaCl) aqueous solution, add 30mL of petroleum ether and shake for 2 minutes, let it stand and separate, and extract the water layer with 20ml of petroleum ether once and combine the extracts. Dehydrate with anhydrous sodium sulfate and blow the petroleum ether with nitrogen to evaporate. Wash the residue with 5mL petroleum ether for 3 times, transfer to the purification column, elute the purification column with 10mL petroleum ether, discard the eluent: elute with 20mlL petroleum ether + acetone, collect the eluent in a 25mL colorimetric tube, blow nitrogen and concentrate to 5mL for chromatographic analysis. 371
GB/T5009.165—2003
5.3 Gas chromatography reference conditions
Chromatographic column: 1.7% OV-17 and 2% QF-1 mixed stationary phase. Carrier: chromorsorb (HP), 2mX3.2mmid), column temperature 180℃, flow rate 50mL/min, injector: temperature 250℃, detector temperature 250℃. 5.4 Chromatographic analysis
Use external standard method for qualitative and quantitative analysis. Take 1μL of 2,4-D butyl ester standard solution and sample solution and inject them into gas chromatograph. Repeat the injection 3 times. The error each time shall not be greater than 5%. Determine 2,4-D butyl ester by retention time and quantify by external standard method of chromatographic peak area. Under the above conditions, the retention time of 2,4-D butyl ester is 3.9min.
6 Results
6.1 Calculation
Calculate according to the following formula:
Where:
AX PX V. × V
-2,4-D butyl ester content in sample, in milligrams per kilogram (mg/kg); -2,4-D butyl ester standard concentration, in micrograms per milliliter (μg/mL); -standard solution injection volume, in microliter (μL): V.
- Sample fixed volume, in mL;- Sample injection volume, in μL; V.
A. Standard color peak area;
Ax- Sample chromatographic peak area;
- Sample mass, in g (g).
6.2 Technical parameters of this section
Method recovery rate: 88.0%~98.2%;
Relative standard deviation: RSD<10%:
Minimum detection amount: MDQ0.01ng;
Minimum detection concentration: When the sampling volume is 20g, the method detection limit is 0.025mg/kg. ECD linear range: 0.01ng~10ng.
7 Gas chromatogram reference diagram
The gas chromatogram is shown in Figure 1.
a) Standard chromatogram of 2,4-D butyl ester
b) Chromatographic diagram of 2,4-D butyl ester sample
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