[CS 67,. 040
National Standard of the People's Republic of China
GH/T5009.19—2003
Generation GB/5C9.191996
Determination of HCH and DDT residues in food Issued on August 11, 2003
Ministry of Health of the People's Republic of China
Standardization Administration of the People's Republic of China
Implementation on January 1, 2004
GB/T5009.19—2003
GB/5333.191 Determination of 666 in Food by Filtration 3. This standard is different from GB/T53.19—1ue in that the Chinese name of the standard has been changed, the name in the standard has been changed to Determination of 666 in Food by Filtration Regulations Part 4 of GB/T20001.4-23315, and the chemical separation method has been revised to form the overall format of the standard.
This standard was proposed by the Ministry of Health of China. This standard was drafted by the Chinese Institute of Preventive Medicine, Nutrition and Food Science. This standard is to start with the following: work, rest, and seek. This standard was first issued in 1980, revised in 1985, and revised for the second time in 1935. This standard stipulates the determination of 666 in food. This standard stipulates the determination method of 666 (IICTI) and TDT residues in food: This standard is applicable to the determination of 666 (TDT) residues in various types of food. GB/T5009.19-2003 ... MR/kg
The detection limit of the recommended chromatography method is 0.02\g, and the return is 2.32μg--C.23g. The first method is gas chromatography
2 Principle
The 666 in the test is extracted and purified by gas chromatography and then determined by chromatographic trapping. The quantitative comparison with the standard is: the electron capture detector has a very high sensitivity to the compound at the negative electrode temperature. The macro-anode can be used to measure the 666, the micro-droplet and the micro-droplet. Different isomers and metabolites can be determined separately.
Result: aHCH.-HH&HCH, HCH./\-DDE.\,*\ [>Io,ULD,P-'-DDT3 wipe
3.1 ketone:
3.? Stop alkali
3.3 full range 0~:
3.5 sulfur:
3.6 anhydrous sodium chain acid
3.7 sodium sulfate solution (23/L).
3.8 pesticide standard into six into HCH.8HCH.YHCH-11C!I degree dropwise P-pF pure
3.9 pesticide standard stock solution: accurately weigh HCH, -HCH.HCH, HCH. "\-DEE..P.DDL and P,c 11 10 g each, float in testis, respectively more than 1cS raL. volume joint, dilute to scale with extract, mix, concentrate, become _20 mg/L, this is stored in the refrigerator.
3.10 Mix the standard working solution of the drug; prepare the standard solution according to the following conditions: the concentration of each standard solution is as follows:
4.1 Gas chromatograph: only capture and detect the microorganism,
4.2 Generator
4.3 V-evaporator.
4.4 Homogenizer.
CB/T 5009.19-—2003
4.5 Multi-purpose condenser.
4.6 Centrifuge,
4.7 Sample crusher.
5. Analysis procedures
5.1 Sample preparation
Cereals are made into powder, and their products are made into uniform powder; fruits and their products are made into uniform powder; eggs are shelled and made into uniform powder; meat products are peeled and tendons are removed, and then the meat is judged as meat; fresh milk paste is made into edible oil paste for later use: 5.2 Extraction
5.2.1 Take 20g of representative sample slurry of various products, such as 5L of water (depending on the water content, the total water content is about 2L), 4g of sodium hydride (11ml), shake for 3min, add 6g of sodium hydride, add 30mL of petroleum ether, shake to 3ml again, take the upper liquid, dehydrate it with sodium anhydride, concentrate it in a rotary evaporator to nearly 30%, make up to 100% by volume with petroleum aldehyde, add 5.5ml of ethanol, shake for 0.5min, dry it, and centrifuge it at 3 0C for 15 minutes. min, take the upper digestion system for GC analysis. 5.2.2 Take a representative 2-valent acid product, add 2 ml of right oil fermentation. Filter for 30 min, filter the liquid, dilute to 5 mL, add 0.5 mL of acid-resistant purification liquid. Analyze at 3 Gnmin for 15 min, take the upper digestion system for C analysis. 5.2.3 Take a representative edible moist sample 0.5 *, dissolve it in 1 mL of oil in a 1 mL scale test tube, dilute to the specified volume. Incubate at 1.3 tL rate for 3.5 min, centrifuge at 3000 r/mrin for 15 min, take the upper digestion system for C analysis. 5.3 Gas Chromatography Packing Column Gas Sweep Other Spectrometer Parts: Chromatographic column: 3 mm long 2-day column, coated with 1.5% 0V-13 and 2-centimeter above! Mixed fixed road 80~100 feet of spherical soil, High purity air flow rate: 0/0m, column temperature 85, detector temperature, sample inlet temperature 195%, single volume 1L~1CL. External standard reaches quantitative. 5.4 Color range
8 The chromatogram of pesticides is shown in Figure 1.
Peak;.23,4GC6+569766G.66c65,6.7.8-DDE.DETPDE,PnDT Figure 1 Chromatogram of pesticides
6 Result calculation
In the test, the single-contained content of 666 and its isomers or metabolites is calculated according to the formula <[), ×*10
Wu Zhong:
Region of single 666 and its isomers or metabolites, unit is rate: East year under gram m/: The olefin value of each component to be determined is <peak separation or area): A
Peak head (peak height wave area) of each pesticide group standard, 15+
Content of single pesticide standard solution, in nanogram (ng); Sample volume of the measured sample, in gram (); V,-screened volume of the measured sample, in milliliter (mI.) V-deduced volume of the measured sample, in microliter (L): 7 Precision
wwW.bzxz.NetCD/T 50C9.192003
The absolute difference of two spot determination results obtained under the condition of chromatographic conditions shall not exceed 15% of the arithmetic mean. The second method is thin-film chromatography
B Principle
BHC in pure water is extracted with an organic solvent and then treated by grinding to remove the major interfering substances, concentrated, spot-developed, and colored with silver nitrate. After ultraviolet irradiation, a brown-black baking spot is generated. Compared with the standard catalyst, the quantitative determination can be roughly obtained. 9 Reagents
In addition to 5.1~3.A, the following reagents are also used. 9.1 Caustic soda: sodium hydroxide,
9.2 Silver sulfate solution (1U g/L).
9.3 Color development solution: weigh 0.59 nitric acid and dissolve several drops in water, add 10mL of ethanol, add 3% hydrogen peroxide, mix and store in a brown bottle in the refrigerator. 9.4 Six people six drops of standard process: take six drops of standard process (3.8>2.0mL: transfer to 1. volume plate, add each to the scale, mix. 2.10 only
except 4.2--4. 7 In addition, the following apparatuses are also available. 10.1 Thin layer or coating apparatus
10.2 Feasible plate, 5m20m
0.3cm25m wide m4cr,
10.4 Degassing fogger
10.5 Radiation killer lamp, 1W
10.6 Combined with mouse injector or blood color pipette, 11 Analysis steps
11,1 Extraction
11.2 Purification
10L extract solution reaches ≤1 ml., 0.1ml. Concentrated acid, cover the test tube, concentrate under irradiation, open to release, and then vibrate for 3.5am: at 1500 1/nn, 15 m, three times to eliminate the concentration and provide other spectrum. 11.3 Determination
11.3.1. Preparation of thin layer plate: Take alumina (0.5g), add 1mL nitrate solution (1Cg/L) and eml. Grind into paste. Then coat. Wash with 500g of 200g of granules, 25mm thick, dry in a 100t drying oven, and place under light. 11.3.2 Spotting, 2cm away from the end of the support layer: use a marker to spot 1l~11T of sample solution and 666, standard drop reduction on the support layer plate: spot 3~4 points on a plate, spot standard lead solution in the middle. Spot the sample on both sides. You can use the filter paper method to spot. 55
GB/T 5009.19—2003
11.9.3 Pre-add 1 mL of acetone-hexane (190) or acetone-sodium 1.1% solution to the developing plate. Scan the plate after the sample is spotted. When the front lead of the reagent is 10 mL away from the origin, take it out and then dry it. 11.3.4 Color development: Spray the developed plate with 10 mL of nitric acid color development solution. After drying, place it under an outdoor lamp 8 cm away for 10 minutes. 20 mir., 666, full drop trace all show my brown black spots. According to the order of the small spots, the product is -DE, -DTr-HCH.-DDY-HCH.HCH.5-HCH.
Results
The single isomers and metabolites of 666 in the sample and its isomers or metabolites are calculated according to formula (2).
x=mx(V.)x1cc
A X1 HO
·-the content of hexachlorobenzene and its isomers or metabolites in the sample, in milligram per gram (mg/kg); A—the content of hexachlorobenzene or its isomers or metabolites in the test solution, in nanogram (n); the total volume of the sample solution, in milliliters (mL); V—the volume of the sample, in microliters (μl); the mass of the sample, in grams (g). 13 Precision environment
The absolute difference between two independent determination results obtained under reconstitution conditions shall not exceed 2% of the calculated average. 156
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