This standard specifies the method for determining the residues of seven pesticides in leeks. This standard is applicable to the residual analysis of methamidophos, phorate, monocrotophos, parathion, isofos-methyl, chlorpyrifos, and carbofuran in leeks. The minimum detection concentrations are (mg/kg): 0.01, 0.01, 0.03, 0.02, 0.01, 0.02, and 0.04. NY/T 447-2001 Method for determining the residues of seven pesticides including methamidophos in leeks NY/T447-2001 Standard download decompression password: www.bzxz.net

NY/T447--2001
Leek is one of the main vegetable varieties in my country. In the process of its growth, the phenomenon of unreasonable use of pesticides often occurs. In order to protect the interests of consumers and producers and provide scientific basis for management departments, this standard provides seven pesticide residue detection methods in leek, including methamidophos, phorate, monocrotophos, parathion, methyl isofenphos, chlorpyrifos, and furadan. This standard is proposed by the Crop Management Department of the Ministry of Agriculture. This standard is drafted by the Pesticide Testing Institute of the Ministry of Agriculture. The main drafters of this standard are: Liu Guangxue, Gong Yong, Qin Dongmei, Tao Chuanjiang, He Yibing, Ye Jiming, Zhu Guangyan, Gao Xiaohui, and Wu Yuhuan. This standard is interpreted by the Pesticide Testing Institute of the Ministry of Agriculture. 219
Agricultural Industry Standard of the People's Republic of China
Method for the determination of pesticide residues in leek
This standard specifies the method for the determination of seven pesticide residues in leek. NY/T 447—2001
This standard is applicable to the analysis of methamidophos, phorate, monocrotophos, parathion, methyl isofenphos, chlorpyrifos and furan in leek. The minimum detection concentrations are (mg/kg): 0.01, 0.01, 0.03, 0.02, 0.01, 0.02 and 0.04 respectively. 2 Principle
Pesticides in the sample are extracted with organic solvents, purified by column chromatography to remove interferences, and detected by gas chromatograph nitrogen-phosphorus detector. The retention time of the chromatographic peak is used for qualitative analysis and the external standard method is used for quantitative analysis. 3 Reagents
All reagents used are analytically pure.
3.1 Acetone.
3.2 Dichloromethane.
3.3 Petroleum ether: boiling range 60～90℃.
3.4 ​​Anhydrous sodium sulfate.
3.5 Sodium chloride.
3.6 Activated carbon (powdered.
3.7 Neutral alumina (200～300 mesh) is baked at 140℃ for 4h, deactivated with 8% water, mixed, and allowed to stand overnight for use. 3.8 Pesticide standards: methyl parathion, phorate, monocrotophos, parathion, methyl isofenphos, chlorpyrifos, furadan. Purity ≥98.0%. 3.9 Pesticide standard solution: Accurately weigh appropriate amounts of pesticide standards listed in 3.8, and prepare standard stock solutions with acetone to a concentration of about 1.0mg/mL, and prepare with acetone as needed. Prepare a mixed standard working solution of appropriate concentration. 4 Instruments and equipment
4.1 Gas chromatograph: equipped with nitrogen-phosphorus detector. 4.2 High-speed tissue crusher.
4.3 Rotary evaporator.
4.4 Glass chromatography column: 18mm×25cm with polytetrafluoroethylene stopcock. 5 Extraction and purification
5.1 Extraction
Approved by the Ministry of Agriculture of the People's Republic of China on June 1, 2001 220
Implemented from October 1, 2001
NY/T 447—2001
Weigh 20.0 g of sample (accurate to 0.1 g), place in a tissue grinder, add 10 g of sodium chloride, 100 mL of acetone and 50 mL of dichloromethane, homogenize at high speed for 1 min, let stand for 10 min, take 100 mL of supernatant in a round-bottom flask, use a rotary evaporator to reduce pressure and concentrate to about 1.0 mL in a 40°C water bath, transfer twice with 10 mL of petroleum ether and continue to concentrate to about 1.0 mL for purification. 5.2 Purification
5.2.1 Prepare a purification column: Fill absorbent cotton, 2 cm high anhydrous sodium sulfate, and petroleum ether in turn and place the petroleum ether liquid level on top of the anhydrous sodium sulfate, weigh Take 4.0g of mixed filler (activated carbon: neutral alumina - 1:4), wet it with petroleum ether and put the petroleum ether liquid level to the top of the filler, then add 2cm high anhydrous sodium sulfate. 5.2.2 Purification: Transfer the concentrated sample to the column twice with 10mL of petroleum ether, and discard the petroleum ether, elute with 150mL of mixed eluent (acetone: petroleum ether - 1:1) and collect, concentrate, and make up to 1.0mlL with acetone for testing. 6 Determination
6.1 Chromatographic conditions
6.1.1 Chromatographic column: HP-170130m×0.25mmX0.25μm. 6.1.2 Chromatographic column temperature: 80℃→1 min-20℃/min-170℃→5℃/min→240℃. 6.1.3 Inlet temperature: 240℃.
6.1.4 Detector temperature: 270℃.
6.1.5 Carrier gas: gas ≥99.999%, 1.3mL/min. 6.1.6 Auxiliary gas: nitrogen 30mL/min, hydrogen (3.0±0.2)mL/min, air 90mL/min. 6.2 Chromatographic determination
According to the content of pesticides in the sample solution, select a similar standard working solution. The response values ​​of pesticides in the standard working solution and the sample solution should be within the detection linear range of the instrument. Under the above conditions, the retention times of various pesticides are (min): Methamidophos
Phorate
Furadan
Monocrotophos
Chlorpyrifos
Parathion
Methyl isofenphos
7 Results
7.1 Calculation
The pesticide residues are calculated according to formula (1):
Es X h,(S,) XVXV
X,=VxH.(S)xmxv,
Where: X.-
Residue of pesticide component i in sample, mg/kg; Content of pesticide component i in standard solution, μg; V—Final volume of sample, mL;
V,—-Injection volume of sample, μL;
Hs(Ss)-
-Peak height (peak area) of component i in standard sample, mm (mm2); -Peak height (peak area) of component i in sample, mm (mm); Total volume of organic phase of extraction solution, mL; Volume of organic phase of extraction solution, mL; Sample amount, g.
·(1)
7.2 Recovery and coefficient of variation of the method
NY/T447--2001
The experimental data of recovery (within different addition concentration ranges) are shown in Table 1. Table 1
Name of pesticide
Methamidophos
Phorate
Monocrotophos
Parathion
Methyl isofenphos
Chlorpyrifos
Furadan
Chromatogram
See Figure 1 for the chromatogram.
Added concentration
0. 01 ~0. 5
0. 01~~0.5
0. 05 ~~ 0. 5
0. 01 ~ 0. 5
0. 05 ~0. 5
Time (min)
Recovery rate
79.7~82.2
80. 0~88. 2
100.798.0
79.3~78.2
82. 4~98. 1
100.0~93.8
82.0~~99. 1bzxz.net
1--Methamidophos; 2-Phorate; 3--Furidophos; 4--Monocrotophos; 5--Chlorpyrifos; 6--Parathion; 7--MethylisothionFig. 1 Chromatogram
Coefficient of variation
8.4~～5. 3
6. 7 ~~4. 4
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