This standard specifies the determination method of diniconazole residues in pears. This standard is applicable to the analysis of diniconazole pesticide residues in pears. The detection limit of this method is 1.0ng. The linear range is 0.1μg/mL～5.01μg/mL. GB/T 5009.201-2003 Determination of diniconazole residues in pears GB/T5009.201-2003 Standard download decompression password: www.bzxz.net

ICS67.040
National Standard of the People's Republic of China
GB/T5009.201—2003
Determination of diniconazole residues in pear2003-08-11Issued
Ministry of Health of the People's Republic of China
Standardization Administration of the People's Republic of China
2004-01-01Implementation
This standard is proposed and managed by the Ministry of Health of the People's Republic of China. This standard is drafted by the Pesticide Control Institute of the Ministry of Agriculture and the Food Hygiene Supervision and Inspection Institute of the Ministry of Health. The main drafters of this standard are Qin Dongmei and Yang Dajin. GB/T5009.201—2003
GB/T5009.201-2003
Diniconazole, trade name: Sumi-eight, chemical name: (E)-1-(2,4-dichlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-2-penten-3-ol. Diniconazole belongs to the triazole fungicide, which has the fungicidal effects of preservation, treatment and eradication. It is a broad-spectrum, high-efficiency, low-residue fungicide. It is mainly used to prevent and control pear black disease, apple powdery mildew and corn smut. This method is established on the basis of referring to the Sumi-eight pesticide detection method of Sumitomo Chemical Co., Ltd. of Japan and combining the instrument and equipment conditions of my country, and is suitable for the determination of diniconazole residues in pears.
1 Scope
Determination of diniconazole residues in pears
This standard specifies the method for determining diniconazole residues in pears. This standard is applicable to the analysis of diniconazole pesticide residues in pears. The detection limit of this method is 1.0ng. The linear range is 0.1μg/mL～5.0μg/mL. 2 Principle
GB/T5009.201—2003
The diniconazole in the sample is extracted with an organic solvent, and the interfering substances are removed by liquid-liquid distribution and column chromatography purification. After concentration and constant volume, it is detected by a nitrogen phosphorus detector (NPD). The qualitative analysis is based on the retention time and the quantitative analysis is based on the external standard method. 3 Reagents
3.1 Acetone.
3.2 Dichloromethane.
3.3 Toluene.
3.4 ​​N-hexane.
3.5 Sodium nitride.
3.6 Anhydrous sodium sulfate.
3.7 Silica gel: for chromatography, 100 days to 200 days, bake at 120℃ for 4 hours, cool to room temperature, add 1.5% water to deactivate, shake for 3 hours, and let stand overnight. 3.8 Diniconazole standard solution: weigh a certain amount of Diniconazole standard substance (purity ≥99.99%), prepare a 1.0 mg/mL standard stock solution with acetone, and stick it in a refrigerator (0℃～4℃). When using, absorb a certain amount of standard stock solution and dilute it with acetone to 1μg/mL standard working solution.
4 Instruments
4.1 Oscillator.
4.2 Chromatographic column: inner diameter 1.5 cm, length 40 cm. 4.3 Rotary evaporator.
4.4 Gas chromatograph: with nitrogen phosphorus detector (NPD). 5 Analysis steps
5.1 ExtractionWww.bzxZ.net
Weigh 30g of sample into a 150mL conical flask, add 40mL acetone, and shake to extract for 1h. Vacuum filter with a Buchner funnel, rinse the residue and filter device with 30mL and 10mL acetone. Collect all filtrates in a 500mL separatory funnel, add 80mL 10% sodium chloride aqueous solution, extract with 40mL difluoromethane for 10min, pass the extract through a funnel filled with anhydrous sodium sulfate, and extract once with 30mL difluoromethane. Combine the extracts, concentrate to about 1mL on a rotary evaporator at 40℃, add 5mL of n-hexane twice to evaporate dichloromethane, and finally concentrate to about 1mL for purification.
5.2 Purification
Plug an appropriate amount of absorbent cotton at the lower end of the glass chromatography column, add about 20mL of n-hexane, and then add 2cm of anhydrous sodium sulfate, 1g of silica gel, and 2cm of anhydrous sodium sulfate. Release the n-hexane until it is level with the surface of the filling material in the chromatography column. Then transfer the above concentrate into the chromatography column, first elute with 8mL of toluene + acetone (95+3), and discard it. Then elute with 10mL of toluene + acetone (4+1), collect the eluent, reduce the pressure to 585
GB/T5009.201—2003
After concentration, dilute to an appropriate volume for gas spectrum analysis. 5.3 Gas chromatography reference analysis conditions
5.3.1 Detector: nitrogen-phosphorus detector.
5.3.2 Chromatographic column: HP-608, 15mx0.53mm×0.5μm. 5.3.3 Column temperature: starting temperature 120℃, holding time 1min→heating rate 50℃/min-end temperature 260℃, holding time 5min.
Injection port temperature: 240℃,
Detector temperature: 260℃.
5.3.4 Gas flow rate: nitrogen (N.) is 3mL/min; hydrogen is 3mL/min;
air is 100mL/min;
auxiliary gas (N.) is 12mL/min.
5.4 Determination
Pipette 2μL of standard solution and sample purification solution and inject them into the chromatograph, and use the retention time for qualitative analysis and the peak height or peak area of ​​the sample to compare with the standard for quantitative analysis.
5.5 Chromatogram
Positive 8R8 product 98
NPDIA, (diniconazole/FNPD0074.D) standard
681012141618min
Figure 1 Standard chromatogram
6 Result calculation
Where:
NPDIA, (vinylpyrrol/FNPD0063.D) pAT
Product R meeting
Sample blank
2141618min
Sample chromatogram
Content of diniconazole pesticide, in milligrams per kilogram (mg/kg); Peak height or peak area of ​​sample;
Peak height or peak area of ​​standard;
Concentration of standard solution, in micrograms per milliliter (μg/mL); Sample mass, in grams (g):
Fixed volume, in milliliters (mL): Calculation results retain two significant figures.
Precision
NPDIA, (diniconazole/FNPD0067.D)PA
Room 589, No. 58328
Sample spike
4681012141618min
Figure 3 Sample spike chromatogram
The absolute difference between two independent determination results obtained under repeatability conditions shall not exceed 20% of the arithmetic mean. 586
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