GB 23200.88-2016Food safety national standard -- Detection of Organochlorine Pesticide Residues in Aquatic Products (English PDF)

4.1 Reagents

4.1.1 Acetone (C3H6O). Distillation.

4.1.2 petroleum ether. boiling range 60-90 ° C after purification by alumina column distillation with an all-glass distiller, collecting 60-90 ° C fractions.

4.1.3 ether (C4H10O). re-distillation.

4.1.4 anhydrous sodium sulfate (Na2SO4). analytical pure; 650 °C burning 4 h, stored in a sealed container in reserve.

4.2 Solution preparation

4.2.1 ether - petroleum ether leaching solution (15 85). take 150 mL of ether, add 850 mL of petroleum ether, shake back.

4.3 Standards

4.3.1 Organochlorine pesticide standards (alpha-BHC, beta-BHC, gamma-BHC, delta-BHC, hexachlorobenzene, heptachlor, epoxidized heptachlor, aldrin O, p'-DDT, p, p'-DDT, p, p'-DDD, p, p'-DDE). purity >=99%.

4.4 Standard solution preparation

4.4.1 14 kinds of organochlorine pesticide standard solution. accurately weighed the right amount of each pesticide standard, respectively, with a small amount of benzene dissolved, and then use petroleum ether A standard stock solution with a concentration of 0.100 mg/mL was prepared. According to the need to then prepare the appropriate concentration of petroleum ether mixed standard working solution.

Store in 4 °C refrigerator.

4.5 Materials

4.5.1 Alumina. chromatography, neutral, 100-200 mesh, 800 °C burning 4 h, cooled to room temperature stored in a sealed container in reserve. before use should be dried at 130 ° C for 2 hours.

4.5.2 Fluorine Silica. 60-100 mesh, 650 °C burning 4 h, stored in a sealed container in reserve. And dried at 130 ° C for 1 hour before use.

Note. Each batch of florisil should be used before the leaching curve.

5.6 Glass mortar. caliber 11.5 cm

5.7 Rotary Evaporator or Nitrogen Flow Concentrator. 250 mL of vials.

5.8 Microiner. 10 µL.

5.9 absorbent cotton. after acetone a petroleum ether (2 8) mixture solution 6 h treatment.

5.10 meat grinder.

7.1 Extraction

Weigh the sample 10.0 g (accurate to 0.1 g) in a mortar, add 15 g of anhydrous sodium sulfate for several minutes, the sample made of dry powder.

Into the filter tube. Into the Soxhlet extractor. Add 100 mL of acetone-petroleum ether (2 8) to the vial of the extractor on a water bath Extraction for 6 h (reflow rate 10-12 times per hour). The extract was concentrated to about 5 mL under reduced pressure or a nitrogen stream.

7.2 Purification

The extract was completely transferred to a florisil silica column. Discard the effluent. Into.200 mL of ether-oil ether eluent for elution.

At the beginning, take part of the ether-petroleum ether mixture to clean the extraction bottle, and the lotion into the purification column. Elution flow rate of 2-3 ML/min, and the effluent was collected in a 250 mL vial. Concentrated in a reduced pressure or nitrogen stream and set to 10 mL, for gas chromatographic determination.

7.3 Determination

7.3.1 Gas Chromatographic Reference Conditions

A) Column. SGE capillary column (or equivalent column), 25 m x 0.53 mm (inner diameter), film thickness. 0.15 µm. Fixed phase. HT5 (not Polar) bond phase;

B) Carrier gas. nitrogen (purity >=99.99%), 10 mL/min;

C) Auxiliary gas. nitrogen (purity >=99.99%), 40 mL/min;

D) Column temperature. the program temperature is as follows.

100 ° C 140 ° C.200 ° C 230 ° C E) Inlet temperature..200 ° C;

F) detector temperature. 300 ° C;

G) Injection method. Stem injection method.

7.3.2 Determination of gas chromatography

According to the organic chlorine in the sample solution, according to the type and content of the organochlorine pesticide in the sample solution, the corresponding standard working mixture with similar peak height is selected.

The reaction value of each organochlorine pesticide in standard working mixture and sample solution should be within the linear range of instrument detection. On the standard working mixture and sample solution Measurement of volume injection. Under the above chromatographic conditions, the sequence and retention time of each organochlorine pesticide were as follows. 1.14 kinds of organochlorine pesticides the chromatogram of the standard is shown in Appendix A.

Table 1 Peak sequence and retention time of organochlorine pesticides

Pesticide name retention time min pesticide name retention time min Alpha-BHC, 10.55 Epoxy Hexachlor 15.04 HCB 10.76 Dieldrin 16.28 Gamma-BHC 11.75 p, p'-DDE 16.44 Beta-BHC 12.10 Endrin 16.75 delta-BHC 12.90 o, p'-DDT 17.12 Heptachlor 13.08 p, p'-DDD 17.44 Aldrin 13.97 p, p'-DDT 17.92

7.4 Blank test

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

10.1 Quantitation limits

Quantitative limits for organochlorine pesticides in this method Appendix B.

10.2 Recovery rate

The concentration and recovery of the sample by gas chromatography are shown in Appendix C.

Appendix A

(Informative)

Standard Chromatography and Mass Spectrometry Appendix B (Informative) Quantitative limits of organochlorine pesticides

Table B.1 Quantitative limits of organochlorine pesticides

Pesticide name quantitative limit, mg/kg pesticide name quantitative limit, mg/kg Alpha-BHC, 0.005 Epoxy Hexachlor 0.02 HCB 0.005 Dieldrin 0.01 Gamma-BHC 0.005 p, p'-DDE 0.02 Beta-BHC 0.005 Endrin 0.02 delta-BHC 0.005 o, p'-DDT 0.025 Heptachlor 0.01 p, p'-DDD 0.025 Aldrin 0.01 p, p'-DDT 0.025 Appendix C (Informative) Sample concentration and recovery of the experimental data

Table C.1 Determination of the concentration and recovery of the sample by gas chromatography

Name of pesticide

Add concentration

(Mg/kg)

Recovery rate

Name of pesticide

Add concentration

(Mg/kg)

Recovery rate

Alpha-BHC

0.005 89.28

Epichlorohydrin

0.02 94.57

0.01 91.15 0.04 92.80 0.05 90.16 0.2 93.00 HCB 0.005 86.24 Dieldrin 0.01 90.04 0.01 89.84 0.02 93.11 0.05 89.93 0.1 93.57 Gamma-BHC 0.005 92.86 P, p'-DDE 0.02 94.71 0.01 93.06 0.04 94.73 0.05 91.26 0.2 95.65 Beta-BHC 0.005 89.5 Endrin 0.02 92.15 0.01 88.54 0.04 91.91 0.05 90.28 0.2 93.45 delta-BHC 0.01 86.14 o, p'-DDT 0.025 93.64 0.02 89.99 0.05 93.54 0.05 90.44 0.25 94.22 Heptachlor 0.05 91.88 p, p'-DDD 0.025 92.00 0.01 92.00 0.05 94.8 0.02 91.91 0.25 96.29 Aldrin 0.01 91.91 p, p'-DDT 0.025 92.89 0.02 91.92 0.05 94.27 0.1 92.67 0.25 94.08 Appendix D (Normative appendix) Laboratory repeatability requirements

Table D.1 Laboratory repeatability requirements

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

Table E.1 Inter-laboratory reproducibility requirements

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