GB 23200.81-2016Food safety national standard -- Method for Detecting the Residue of West Majin in Meat and Meat Products (English PDF)

4.1 Reagents

4.1.1 anhydrous sodium sulfate (Na2SO4). 650 °C burning 4 h, set the dryer in the spare.

4.1.2 Florisil. for chromatography, 100-200 mesh, at 650 °C for 4 h, before drying at 130 °C for 5 h, after cooling stored in dense Closed container, spare.

4.2 Solution preparation

4.2.1 Acetone-petroleum ether mixed solution (15 85). Take 150 mL of acetone, add 850 mL of petroleum ether and shake well.

4.2.2 Dichloromethane - methanol mixed solution (9 1). take 900 mL of dichloromethane, add 100 mL of methanol, shake back.

4.3 Standards

4.3.1 Xi Ma Jin standard. purity >= 98%.

4.4 Standard solution preparation

4.4.1 Simaxin standard solution. accurately weighed the appropriate amount of Simazine standard, with acetone prepared into 100 µg/mL standard stock solution, according to Need to re-use acetone diluted to the appropriate concentration of standard working solution.

6.1 Preparation of the sample

A sample of about 1 kg was taken from all the samples taken. The sample was sampled according to GB 2763 Appendix A, Mix, are divided into two, respectively, into the clean container as a sample. Sealed and marked.

6.2 Sample storage

The sample was stored at -18 ° C or lower.

During sample and sample preparation, the sample should be protected from contamination or changes in the residue content.

7.1 Extraction

Weigh the sample about 30 g (accurate to 0.01 g). Add 30 g of anhydrous sodium sulfate, ground into powder, into the conical flask. Add 100 mL Dichloromethane - methanol (9 1) mixture, ultrasonic oscillation 20 min. Filtrate with a cloth funnel to retain the filtrate. The residue was then washed with 100 mL of dichloromethane Alkane-methanol (9 1) mixture, as described above. The filtrate was combined in a vial of rotary evaporator. And dried in a 50 ° C water bath under reduced pressure dry.

7.2 Purification

The residue was dissolved three times with 20 mL of acetone-petroleum ether (15 85) and the solution was poured into a florite column. With 100 mL Acetone - petroleum ether (15 85), controlled flow rate of 2-3 drops per second, and the effluent was received in an evaporating flask of rotary evaporative liquid. Water at 60 ° C Bath in the bath to dry. With acetone to 5.0 mL, for GC determination.

7.3 Determination

7.3.1 Gas Chromatographic Reference Conditions

A) Column. HP-1.5 mx0.53 mm (id), film thickness 2.65 m.

B) Column temperature. 155 ° C.

C) Inlet temperature. 240 ° C.

D) Detector temperature. 250 ° C.

E) Carrier gas. nitrogen, purity greater than or equal 99.99%, 40 mL/min.

F) Hydrogen. 2 mL/min.

G) air. 140 mL/min

H) Injection volume. 2 µL.

I) Injection method. No split injection.

7.3.2 Chromatographic determination

According to the sample solution of the content of Sima Jin, selected peak area similar to the standard working solution, the standard working solution and sample solution in the West Majin the response value should be within the instrument detection linear range. Standard working solution and sample solution volume measurement. In the above chromatographic conditions , The retention time of Simaxin was 2.2 min. The chromatogram of the standard sample is shown in Figure A1 in Appendix A.

7.4 Blank experiment

In addition to the sample, according to the above determination steps.

10.1 Quantitation limits

The limit of quantification of this method was 86 mg/kg.

10.2 Recovery rate

When the addition level was 0.02 mg/kg, 0.05 mg/kg and 0.1 mg/kg, the recovery of Simazine was 89.6-91.4%.

Appendix A

(Informative)

Standard chromatogram

Figure A1 Chromatogram of standards

Appendix B

(Normative appendix) Laboratory repeatability requirements

Table B.1 Laboratory repeatability requirements

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