This standard specifies the sampling and determination methods for dithiocarbamate residues in apples for export. This standard applies to the inspection of dithiocarbamate residues (including mancozeb, thiram, etc.) in apples for export. SN 0157-1992 Inspection method for dithiocarbamate residues in fruits for export SN0157-1992 Standard download decompression password: www.bzxz.net
This standard specifies the sampling and determination methods for dithiocarbamate residues in apples for export. This standard applies to the inspection of dithiocarbamate residues (including mancozeb, thiram, etc.) in apples for export.

1 Subject content and scope of application This standard specifies the inspection of dithiocarbamate residues in apples for export. 2 Sampling and sample preparation 2.1 Inspection lot No more than 500 pieces of products shall constitute one inspection lot. 2.2 Sample size 2.3 Sampling tools and methods Inspection method for dithiocarbamate residues in apples for export. The products in the same inspection lot shall have the same characteristics, such as packaging, marking, specifications, grades, etc.
Minimum sampling,
randomly select sampling points from various parts of a batch of goods, and select no less than 500g from each point as the original sample. The total amount of the original sample shall not be less than 4kg. 2.4 Preparation of test samples
The sample should be properly compressed after recording and adding allergic diseases. The single grass fruit shall not be cut. The sample preparation shall remove the obvious deterioration and apparent edible amount. When receiving the sample, it shall be chopped quickly.
2.5 Sample preservation
evenly, and immediately operate according to 3.4.1
After the sample is retrieved, it shall be refrigerated in a closed container if it is not inspected on the same day. Note: during sampling
3 Determination method
3.1 Method summary
The sample is contaminated and any changes occur in the closed system
3.2 Reagents and materials
Wang Luodu welcome! In the case base
Acetone: analytical grade, does not contain substances that interfere with the chromatographic peak of carbon under the test conditions
3.2.2 Hydrochloric acid solution (5 mol/L): Measure 430 mL of concentrated hydrochloric acid (analytical grade) and dilute it to 1000 mL. 3.2.3 Stannous chloride solution: Dissolve 15 stannous chloride (analytical grade) in an appropriate amount of hydrochloric acid solution (3.2.2) and dilute to 1L with hydrochloric acid solution. Carbon disulfide standard solution:
Accurately and competently
Diluted to the applicable concentration
3. 3 Instruments and equipment
~0.6g carbon disulfide (analytical grade
1 Gas chromatograph equipped with electron capture detector. 3.3.1
SH0157—9
ZEB31015—88
After completion, put it into a clean
sulfur content
re-distilled) in a 50mL volumetric flask filled with a small amount of acetone and make up to volume with acetone. Acetone can be used again before use. 3.3.2 Headspace bottle: 250mL, which can be replaced by a 250mL plasma bottle equipped with a T-shaped rubber stopper and aluminum cap. 3.3.3 Airtight syringe: 100~250 μL 3.3.4 Microsyringe: 10~~100 μL 3.3.5 Constant temperature water bath 3.4 Determination steps 3.4.1 Sample pretreatment 3.4.1.1 After the sample is prepared, immediately prepare the sample 1.2 Add 50 ml of stannous chloride solution (3.2.3) to the headspace bottle. Pre-empty the bottle 3.3.21. Quickly seal the headspace bottle. 3.4.1.3 Place the headspace bottle in a 80±2℃ water bath (3.3.5) and heat for 1 hour. Take it out every 15 minutes and shake vigorously to prevent the contents from splashing onto the rubber stopper.
3.2 DeterminationWww.bzxZ.net
3.4.2.1 Chromatographic strip
=, Chromatographic column: glass column, 2m×2.5mm (inner diameter), filled with 20% (mm) 0V-101 coated on GasChrom1 (0~100 mesh): b. Column temperature; 60℃
. Inlet and detector temperature: 200℃:
d. Carrier gas: high-purity nitrogen, purity>99.99x, 40mL/min3.4.2.2 Chromatographic determination
Chemical shock gas tightness injection timer (. ) Take the pre-empty period, that is,
3.4.3 Preparation of standard carbon disulfide gas
Range: Take several pre-empty bottles with water
3.5 Blank test
Use water instead of the sample and carry out the steps listed in 3.4.1 and 3.
3.6 Calculation of results
2.2
Calculate the pesticide residue using a chromatography data processor or the following formula: t Where:
h-sample headspace
Standard male head
2(3.3.11. Compare the peak height with that of standard carbon disulfide gas and calculate the carbon disulfide content (in terms of Cs, mgi) according to Section 3.6. Use a microsyringe to inject different amounts of X into each headspace bottle.
Carbon disulfide peak height, mm
l - mass of carbon disulfide added to the headspace bottle when preparing standard carbon disulfide gas, μg; m - mass of sample,
Note: @ Calculation result
headspace White value deduction
② The amount of dithiocarbamate residues. Generally measured in terms of mancozeb. One molecule of mancozeb produces two molecules of carbon disulfide in an acid solution. Additional remarks:
This standard was proposed by the State Import and Export Commodity Inspection Bureau of the People's Republic of China
This standard was drafted by the Henan Import and Export Commodity Inspection Bureau and the Hubei Import and Export Commodity Inspection Bureau of the People's Republic of China. The main drafters of this standard are Yang Jizhou and Lu Kangquan. Carbon disulfide standard solution should cover an appropriate content
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