GB 23200.80-2016Food safety national standard -- Determination of Dithiophos Residue in Meat and Meat Products (English PDF)

4.1 Reagents

4.1.1 acetonitrile (C2H3N). pesticide residues.

4.1.2 Methanol (CH3O). Pesticide level.

4.1.3 Trichloromethane (CHCl3). Pesticide level.

4.1.4 ethyl acetate (C4H8O2). pesticide residues.

4.1.5 n-Hexane (C6H14). Pesticide level.

4.1.6 anhydrous sodium sulfate (Na2SO4). 650 °C burning 4 h, stored in a sealed container after cooling and standby.

4.2 Solution preparation

4.2.1 Sodium Sulfate Solution. 5% aqueous solution.

4.2.2 acetonitrile - methanol mixture (4 1, v/v). take 400 mL of acetonitrile, add 100 mL of methanol, shake back.

4.2.3 Ethyl acetate-n-hexane mixture (3 7, v/v). Take 300 mL of ethyl acetate, add 700 mL of n-hexane and shake well.

4.3 Standards

4.3.1 Sulfophosphate standard substance. purity >=98.0%

4.4 Standard solution preparation

4.4.1 Dithiophosphoric acid standard solution. accurately weighed the appropriate amount of bisphosphorus standard, with a small amount of benzene dissolved, and then with n-hexane prepared into the concentration of 2.0 mg/mL standard stock solution, stored in the refrigerator. If necessary, dilute with n-hexane to the standard working solution at the appropriate concentration.

4.5 Materials

4.5.1 Florisil Column. 4 g.

6.1 Preparation of the sample

To replace the sample of about 1000 g, crushed by grinding, mixing, are divided into two, respectively, into the clean container as a sample, sealed, and mark the mark.

6.2 Sample storage

The sample was stored at -18 ° C or lower. During the operation of the sample preparation, it is necessary to prevent contamination of the sample or change in the content of the residue.

7.1 Extraction

Weigh about 10 g of sample (accurate to 0.1 g) in a conical flask and add 50 mL of acetonitrile-methanol mixture (4 1, v/v) for 30 min.

Centrifuge at 4000 rpm for 15 min, remove the supernatant in a separatory funnel. And then three times with 3 × 25 mL methanol washing the sample three times, wash with the former the supernatant was combined in the same separatory funnel.

7.2 Purification

In the above-mentioned separatory funnel by adding 100 mL of sodium sulfate aqueous solution and 50 mL of chloroform, shaking 5 min, standing stratification, the next the layer of the chloroform solution was introduced into a flask through a funnel containing anhydrous sodium sulfate. And then separately with 50 mL of chloroform extraction twice, combined with trichloride V - the total volume after dilution of the sample in liters (L);

M - sample mass in grams (g).

Note. The result of the calculation shall be deducted from the blank value. The result of the measurement shall be expressed as the arithmetic mean of the parallel measurement, and two valid digits shall be retained.

10.1 Quantitation limits

The limit of quantification of the method is 0.1 mg/kg.

10.2 Recovery rate

When the addition level is in the range of 0.1 ~ 1.0 mg/kg, the recovery of dithiophosphate is 83.6% ~ 103.2%.

Appendix A

(Informative)

Spectrum of bisulfophosphate standard solution 4 .0 06.08.00 01.00 01.2.01.4006.60.08.80.00.00 T ime - - > A bundance TIC. STD 1 1 .D \\ data .ms 1 8 .0 1 2

Figure A.1 Total ion chromatogram of bisulfophosphate standard solution

5 0 1 0 0 1 5 0 2 0 0 2 5 0 3 0 0 3 5 0 4 0 0 4 5 0 5 0 0 M/z - - > A bundance A verageof 1 9 .7 5 5 to 1 9 .8 0 8 m in.. TEMESTD 3 .D \\ DATA .MS (-) 2 3 1 4 3 43 7 22 6 36 9 3 1 3 4 0 32 9 31 4 7 5 0 3

Figure A.2 Total sweep mass spectra of bisulfophosphate standard solutions

Appendix B

(Normative appendix) Laboratory repeatability requirements

Table B.1 Laboratory repeatability requirements

Measured component content Mg/kg RSD <=0.001 36 > 0.01 > 1 14 Appendix C (Normative appendix) Inter-laboratory reproducibility requirements

Table C.1 Inter-laboratory reproducibility requirements

Measured component content Mg/kg RSD <=0.001 54 > 0.01 > 1 19