This standard specifies the method for determining the residue of thiophanate-methyl in cucumbers. This standard is applicable to the determination of residues in cucumbers that have been treated with thiophanate-methyl pesticide. The detection limit of this standard on cucumbers is 0.12×10 GB/T 5009.105-2003 Determination of residue of thiophanate-methyl in cucumbers GB/T5009.105-2003 Standard download decompression password: www.bzxz.net

1C9 67. 040
National Standard of the People's Republic of China
GB/T 5009.105--2003
Recommendation 614875:-1994
Determlnation af chlorothalonil residues in cucumber Issued on August 11, 2003
Ministry of Health of the People's Republic of China
National Standardization Administration of China
Implementation on January 1, 2004
GB/T5009.105—2003
This standard represents GB1487R—1994 Method for the determination of the amount of primary microorganisms in food. Compared with GB1487R—1991, the following contents are included: The Chinese name of the standard has been changed. The Chinese name of the standard is Determination of the amount of primary microorganisms in food: According to the provisions of GR/T20001.4—2001, Part 4: Chemical analysis methods, the original standard has been modified.
This standard was proposed and implemented by the Ministry of Health of the People's Republic of China. The drafting unit of the standard is: Agricultural Residues Analysis Group, Department of Plant Protection, Hebei University of Science and Technology, and Food Hygiene Supervision and Inspection Institute of the Ministry of Health. The main authors of this standard are Shi Jian and Shen Zaizhong. The original standard was first issued in 1354 and this is the first revision. 1 Scope Determination of the residue of fungus chlorpyrifos in cucumber This standard specifies the determination method of fungus chlorpyrifos in cucumber. This standard is applicable to the determination of the minimum retention amount of pesticide in fungus solution. The detection limit of this standard on cucumber is 0.12×1:1* The detection limit is 18m8/kg2 Principle GB/T 5009.105—2003 The pesticide in the sample is extracted with chlorpyrifos and determined with a gas chromatograph with an electronic scanning carbon detector after purification, and the quantitative comparison is compared with the standard. Baiquqing contains highly electronegative hydrogen atoms. The content of Baiquqing in bamboo shoots was calculated by using an electron capture detector. 3 Reagents
3.1 Flocculants (60-80 days).
3.2 Anhydrous sodium sulfate, analytical grade.
3.3 Propane, analytical grade.
3.4 ​​Butanone, analytical grade.
3.5 Hexane: analytical grade.
3.6 Acid, analytical grade,
3.7 Chlorothalonil standard solution: accurately weigh the white bacteria (chlorothalanil> standard + used standard preparation, put on ice:
3.8 Use of standard preparation: reduce the preparation to 4.1/m1.. Store in a box for later use 4 Collectors
4.1 Gas chromatograph, which has \NiECL. 4.2 Transfer to a centrifuge,
4.3 Tissue crusher:
4.4 Chromatography ±, 1cm (inner diameter) × 20cm. 4.5 Separation hopper 250L
4.6 Flour flask, 150mL
5 Analysis step ||t t||5.1 Extraction
Take 250mL cucumber pulp, accurate to 1001g, put it in a 250mL flask, add 20mL of acetone and 50% caustic soda, filter it, wash it with 20mL of acetone, transfer all the liquid into a 250mL separating funnel, add 105mL of 20% sodium sulphate solution, and pipette it once with a ring at 60°C. After static stratification, add anhydrous sodium sulphate to dry the extract, reduce the remaining liquid to 5mL for purification.
5.2 PurificationbZxz.net
Transfer the chromatography column to a small amount of absorbent cotton, add 2cm of hydrolyzed acid, 7mL of silica gel, 2cm of anhydrous sodium sulphate, and shake it into a flat plate. Then use 15% cyclohexane to elute the sample. Discard the pre-elution solution: take the concentrated sample and inject it into the syringe, elute it with 100 μL cyclohexane (20:1) solution, collect the eluent, concentrate it and make it to volume, and perform gas chromatography analysis. 23
GB/T 5009.105—2003
5.3 Chromatographic spare parts
5.3.1 Chromatographic column: a glass column with a length of 1.5 and an inner diameter of 3mm. Filled with ChroDorb WHP (8u~1UU) coated with 1.5V-17+2.5% 0V-210
5.3.2 Column pin degradation: 194mm.
5.3.3 Detector sensitivity: 255T
5.3.4 Secondary chamber sensitivity: 260%:
5,3.5 Pulse selection, 2.
5. 3.6 White high-purity; 4.
5. 3.7 Transmission height group; 0 0.
5.3.8 High-purity air (99.99%) flow rate 30mL/min.5.3.9 Paper speed, 5mm/min.
5.4 Instrument sensitivity: Inject the standard working solution 1F~10M into the gas chromatograph, measure the peaks obtained from the standard solution with different concentrations, and at the same time take 2μL of the sample solution and inject it into the gas chromatograph, compare the measured peak height with the peak height of the standard solution, and calculate the corresponding sum.
5.5 Calculation of results
Then calculate with the following formula:
h+c, -O,- V.
h,·m·Q.
Wherein:
c.-.-Chengbaiconazole content, the unit is gram per gram (mg/kg)Fh…． 1. Sample volume, in millimeters (mm); 2. Standard solution injection, in microliters (L); 3. Sample volume, in liters (mL); 4. Standard solution peak height, in millimeters (mm); 5. Sample weight, in grams (g); 6. Sample solution injection volume, in liters (mL); 7. Chromatogram, in chromatogram, see 1. This product is a product of Baishouqing.
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