GB 23200.49-2016Food safety national standard -- Determination of permethine residues in food by gas chromatography-mass spectrometry (English PDF)

4.1 Reagents

4.1.1 Ethyl acetate (C4H8O2). Chromatographic purity.

4.1.2 n-hexane (C6H14). pure chromatography.

4.1.3 Acetone (C3H6O). Chromatographic pure.

4.1.4 anhydrous sodium sulfate (Na2SO4). 650 °C burning 4 h, placed in a closed container for use.

4.2 Solution preparation

4.2.1 N-Hexane Acetone (3 2, V/V) Mixing Solvent. Take 300 mL of n-hexane, add.200 mL of acetone and mix well.

4.3 Standards

4.3.1 Phenylethylenediamine standard substance (Difenoconazole, C19H17Cl2N3O3, CAS

5.3 Solid phase extraction device with vacuum pump.

5.4 Tissue crusher.

5.5 Crusher.

5.6 Centrifuge.

5.7 Rotary Evaporator.

6.1 Preparation of the sample

6.1.1 Vegetables or fruits

500 g of the sample was taken and the mixture was chopped and the sample was processed into a slurry by a pulverizer. Mix, are divided into two as a test Sample, into the clean container, sealed and marked.

6.1.2 Tea, nuts and cereals

500 g of the representative sample was taken, pulverized by a pulverizer and passed through a 2.0 mm round hole sieve. Mix well, into a clean container, sealed and marked Mark.

6.1.3 Meat and meat products

After picking 500 g of the sample, it was chopped and the sample was processed into a slurry by a mashing machine, and the mixture was packed into a clean bag Inside, sealed and marked.

6.1.4 Spices

Replace the sample 500 g, mix, sub-packed into a clean container, sealed and marked.

6.1.5 Bee products

Take a representative sample volume of 500g, the crystallization of honey samples will be evenly stirred; on the crystallization of honey samples, in the closed the case, the sample bottle placed in not more than 60 °C in the water bath in the warm, shaking, until the sample all melted and stir well, quickly cooled to room temperature, in the melting must pay attention to prevent moisture evaporation. The prepared samples were divided into two separate sections, which were sealed in a vial and sealed Remember.

Note. The above sample sampling site according to GB 2763 Appendix A implementation.

6.2 Sample storage

Tea, bee products, condiments and cereals and other samples stored at 4 °C; fruits and vegetables and meat and meat products such as samples at -18 °C the following frozen storage.

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

7.1 Extraction

For samples with low water content or higher fat content (tea, rice, beans, meat and meat products, bee products, etc.), Take 5 g homogeneous sample (accurate to 0.01 g). For samples with high water content (vegetables, fruits, soy sauce and vinegar spices, etc.), Take 10 g homogeneous sample (accurate to 0.01 g). Place the weighed sample in a 250 mL stoppered flask with 50 mL of ethyl acetate Into 15 g of anhydrous sodium sulfate, placed in the oscillator for 40 min, filtered in 150 mL concentrated bottle. Add 20 mL of ethyl acetate to repeat the extract was extracted once and the extract was concentrated at 40 ° C under reduced pressure to dryness. With 3 mL of n-hexane dissolved, to be purified.

7.2 Purification

7.2.1 High pigmented samples

The activated carbon column and the neutral alumina column in series, followed by 5 mL of acetone, 5 mL of n-hexane activation, the n-hexane extraction solution Column, after the end and then 3 mL n-hexane cleaning bottle and column, to maintain the droplet flow rate of about 2 mL/min, remove the filtrate, dry, with 5 mL N-hexane acetone (3 2, V/V), and the eluate was collected in 10 mL of small tubes and dried in a water bath at 40 ° C, 1.0 mL with n-hexane, and 0.45 µm organic phase filter, gas chromatography-mass spectrometry and confirmation.

7.2.2 Bee products or samples with high fat content

The florisil silica solid phase extraction column was successively activated with 5 mL of acetone and 5 mL of n-hexane, and then the n-hexane extraction solution was passed through the next step is the same as 7.2.1.

7.3 Determination

7.3.1 Gas Chromatography - Mass Spectrometry Reference Conditions

A) Column. quartz elastic capillary column DB-17ms, 30 m × 0.25 mm (id), film thickness 0.25 µm, or equivalent.

B) Column temperature..200 ° C 10 ° C/min 300 ° C (10 min).

C) Inlet temperature. 300 ° C.

D) chromatographic - mass spectrometer interface temperature. 280 ° C.

E) Carrier gas. helium, purity >=99.999%, flow rate 1.0 mL/min.

F) Injection volume. 1 µL.

G) Injection method. no split injection, 1.5 min after the valve.

H) ionization mode. NCI.

I) Ionization energy. 216.5 eV.

J) ion source temperature. 150 ° C K) Quadrupole temperature. 150 ° C L) Reaction gas. methane, purity greater than or equal to 99.99%, reaction gas flow rate. 2 mL/min.

M) Detection mode. Select the ion monitoring mode (SIM).

N) Select the monitoring ion (m/z). Quantitative ion 348; Qualitative ions 310, 350, O) solvent delay time. 12 min.

7.3.2 Determination and confirmation of chromatography

According to the sample solution of phenylephate content of the case, select the peak area similar to the standard working solution, the standard working fluid and sample solution Product feed. The corresponding values of difenoconazole in the standard working solution and sample solution should be within the linear range of the instrument.

If the sample solution is in the selective ion chromatogram of the standard working solution, a chromatographic peak appears at the same retention time, in the sample quality chromatogram, the selected ions are present, the abundance of the selected ions is greater than the abundance ratio of the corresponding ions Within the allowable range (see Table 1). Under the conditions of 7.3.1, the retention time of difenoconazole is 15.74 min, which monitors the ions (M/z) abundance ratio of 310. 348. 350. 405 = 45. 100. 67.13; according to the quantitative ion m/z348 to its External standard method. In the case of 7.3.1, the total ion chromatogram and full scan mass spectrum of the petroleum ether-mass spectrometer Appendix A, Figure A.1 and Appendix B, Figure B.1.

Table 1 Maximum allowable error for relative ion abundance using gas chromatography-mass spectrometry

7.4 Blank experiment

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

10.1 Quantitation limits

The quantification limit of this method is 0.005 mg/kg.

10.2 Recovery rate

When the levels were 0.005 mg/kg, 0.10 mg/kg, 0.20 mg/kg, the addition of phenacillin pesticides in different substrates See Appendix C. for the yield.

Relative abundance (base) 50% 20% to 50% 10% to 20% <=10% Allowable relative deviation ± 20% ± 25% ± 30% ± 50% Cx = as · m Ax Cs Vx Appendix A (Informative) Optic Acid Chromatogram of Standard Solution GC-MSD/NCI CLAIMS 13.00 14.00 15.00 16.00 17.00 18.00 19.00 Time - > Abundance Ion 348.00 (347.70 to 348.70). ZiSu-Spike-21.D 15.74

Figure A.1 Standard solution of phenacillin (0.1 µg/mL) GC-MS/NCI Selective ion chromatogram

Appendix B

(Informative)

Determination of the standard solution GC-MSD/NCI full scan of mass spectrometry 40 60 80 100 120 140 160 180.200 220 240 260 280 300 320 340 360 380 400 M/z - > Abundance Average of 22.596 to 22.615 m in .. DIFENO CO NAZO LE-STD-SCAN-02.D 36994 236 258162

Figure B.1 Standard solution for difenoconazole (2.0 µg/mL) GC-MSD/NCI full scan mass spectrometry

Appendix C

(Informative)

Recovery of Diclofenac from Different Food Substrates

Table C.1 Data on the recovery of difenoconazole in food under three added levels

sample name

Average recovery and coefficient of variation at different levels of addition 0.005 mg/kg 0.010 mg/kg 0.020 mg/kg Average recovery rate(%) RSD (%) Average recovery rate(%) RSD (%) Average recovery rate(%) RSD (%) Peas 94.5 5.7 89.8 3.4 97.0 5.0 Perilla 100.0 8.0 95.9 9.4 96.9 10.4 Carrot 92.4 12.2 89.9 11.5 99.1 6.2 Spinach powder 93.7 7.7 97.2 5.7 98.0 6.7 Rice 93.2 8.2 98.9 7.6 95.2 8.0 Soybeans 90.0 6.4 92.4 5.3 86.4 4.0 Polygonatum 105.1 7.8 95.1 4.9 79.7 3.0 Jasmine Tea 102.9 5.6 104.7 4.8 103.7 4.7 Oolong tea 76.1 5.4 81.8 9.5 88.8 3.6 Almond 81.6 4.7 84.3 10.9 85.6 10.3 Grapefruit 72.5 3.5 78.3 7.5 91.0 5.8 Pineapple 72.3 5.8 81.1 11.4 87.4 3.5 Strawberry 84.0 7.9 83.3 7.5 85.7 2.7 Soy sauce 85.9 5.5 95.0 5.8 98.3 4.0 Vinegar 74.3 5.1 76.8 7.4 81.8 5.2 Honey 67.2 7.2 71.4 7.2 76.5 5.8 Dry powder 68.4 7.7 79.4 7.1 65.0 5.9 Pork 79.5 6.7 88.7 8.1 93.1 4.2 Bovine meat 81.6 6.7 86.7 10.2 91.7 3.4 Chicken wings 88.5 7.3 96.5 6.6 99.1 5.6 Live eel 104.0 7.2 102.4 4.6 91.4 5.1 Lobster 80.0 7.5 92.9 8.1 98.1 4.3 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