SN 0491-1995Method for detection of phenflusulfamine residues in foods of plant origin for export (English PDF)

5.2 Gas tandem mass spectrometer. Equipped with electron impact ionization source (EI)

5.3 Organization of mashers.

5.4 Electronic balance. Sensitivity is 0.01g and 0.1mg respectively.

5.5 Centrifuge. The rotation speed is not less than 5000r/mm.

5.6 Homogenizer. The rotation speed is not less than 1500r/min.

5.7 Nitrogen blowing instrument.

5.8 Rotary evaporator.

5.9 Solid-phase extraction device.

5.10 Polypropylene centrifuge tubes. 50mL and 15mL, with stoppers.

5.11 10mL glass graduated test tube.

5.12 Chicken heart bottle. 120mL.

6.1 Sample preparation requirements

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

6.2 Sample preparation

6.2.1 Pear, grape, potato, tomato, cucumber, mushroom and dried pepper

Take a representative sample of 500g, pear, tomato, cucumber and dried pepper to take the whole fruit and remove the handle; grapes to take the whole fruit. potatoes and mushrooms take the whole one, use a masher to process the sample into a slurry and mix. The samples were divided into two parts, put into clean containers, sealed and marked. Below -18 °C Cryopreserved.

6.2.2 Rice, corn, wheat, soybeans and brown rice

Take a representative sample of 500g, take the whole grain, crush it with a pulverizer, and mix. The samples were divided into two parts, put into clean containers, sealed and marked. Store at room temperature.

7.1 Extraction

7.1.1 Pear, grape, potato, tomato, cucumber and mushroom

Weigh about 5g of the sample (accurate to 0.01g) into a 50mL centrifuge tube, add 10g of anhydrous sodium sulfate (4.5), 20mL of acetonitrile (4.1), 1500r/min was homogeneously extracted for 2min, 4,000r/min was centrifuged for 10min, and the supernatant was filtered through a funnel containing 10g of anhydrous sodium sulfate (4.5) into a 120mL chicken heart bottle. Repeat the above extraction process with 15mL of acetonitrile. Combine the extracts in the same chicken heart bottle at 45 ° C.

Concentrate the water bath to dryness and wait for purification.

7.1.2 Rice, corn, wheat, soybeans, brown rice and dried peppers

Weigh about 2g of dried pepper sample, about 5g (accurate to 0.01g) of rice, corn, wheat, soybean and brown rice sample in 50mL centrifuge tube SN/T 0491-2019 Add 10mL of water to wet the sample, mix it for 2min, leave it for 30min and add 10g of anhydrous sodium sulfate (4.5), 20mL of acetonitrile (4.1), 1500r/min homogeneous extraction 2min, 4,000r/min centrifugation 10min, the supernatant was passed through a funnel containing 10g anhydrous sodium sulfate (4.5) Strain into 120mL chicken heart bottle. Repeat the above extraction process with 15mL of acetonitrile. Combine the extracts in the same chicken heart bottle at 45 ° C.

Concentrate the water bath to dryness and wait for purification.

7.2 Purification

Dissolve the concentrate obtained in step 7.1 with 5 mL of n-hexane (4.2). Pre-washed silica gel solid phase extraction with 5 mL of n-hexane (4.2) Column (4.12), pass the sample extraction solution through the solid phase extraction column, rinse the solid phase extraction column with 6 mL of n-hexane-diethyl ether (4.6) solution, and discard all the flow the effluent was eluted with 2 mL of n-hexane-diethyl ether (4.7) solution. The entire effluent was collected and dried at 45 ° C under nitrogen. With 2.0mL of n-hexane (4.2) After dissolution, after passing through the 0.22 µm organic phase microporous membrane, it is provided for gas chromatography determination and gas chromatography-mass spectrometry confirmation.

7.3 Gas chromatography

7.3.1 Gas chromatography reference conditions

The gas chromatography conditions are as follows.

a) Chromatographic column. DB-1701 quartz capillary column, 30m × 0.25mm (i.d), 0.25µm, or equivalent;

b) Column heating program. 80 ° C (2min) 30 ° C/->/min200 ° C 5 ° C/-> min250 ° C (3min);

c) inlet temperature. 250 ° C;

d) Detector temperature. 300 ° C;

e) Carrier gas. nitrogen, purity 99.99%, flow rate. constant current mode 3mL/min;

f) sampling method. no split;

g) Injection volume. 2.0 µL.

7.3.2 Determination by gas chromatography

Under the optimal working conditions of the instrument, gas chromatography was quantified by external standard method. Select the peak surface according to the content of the analyte in the sample solution Accumulate similar standard working solutions. The response value of the test substance in the standard working solution and sample solution should be within the linear range of the instrument.

Beyond the linear range, dilute with n-hexane (4.2) to the appropriate concentration and analyze. The standard working solution and the sample solution are sampled at the same volume.

Under the above chromatographic conditions, the reference retention time of phenflusulfamine is about 12.07 min. The gas chromatogram is shown in Figure A of Appendix A. 1.

7.4 Confirmation by gas chromatography-mass spectrometry

7.4.1 GC-MS reference conditions

The GC-MS conditions are as follows.

a) Chromatographic column. DB-5MS (30m × 0.25mm × 0.25µm) quartz capillary column, or equivalent;

b) Column temperature program. Hold at 60 ° C for 2 min, then raise the temperature to 220 ° C with the 30 ° C/min program, and then raise the temperature at 5 ° C/min.

To 250 °C, keep 5min;

c) inlet temperature. 250 ° C;

d) Chromatography-mass spectrometry interface temperature. 280 ° C;

e) Ion source temperature. 230 ° C;

f) Carrier gas. Helium, purity >=99.99%, flow rate 1.0mL/min;

g) Sample injection method. splitless injection. After 1.0 min, open the split valve and septum purge valve;

h) Ionization method. electron impact source (EI);

i) Injection volume. 1 µL;

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j) Measurement method. Select ion monitoring method;

k) Selecting monitoring ions (m/z). 123, 167, 224, 332 (abundance ratio 100. 45. 30. 6).

l) Solvent delay. 6 min;

m) Ionization energy. 70 eV.

7.4.2 Confirmation by gas chromatography mass spectrometry

It is confirmed that the retention time of the chromatographic peak of the analyte is consistent with that of the standard sample, and the sample spectrum after the background subtraction is selected.

All ions appear; at the same time, the abundance ratio of the selected ions is consistent with the relative abundance of related ions in the standard sample, and the similarity is within the allowable deviation.

(See Table 1), then the sample can be determined to be positive for fenflusulfa. GC-MS selective ion chromatogram of phenylsulfonamide standard material and the mass spectrum is shown in Figure A in Appendix A. 2 and A. 3.

Table 1 Maximum allowable error of relative ion abundance during qualitative confirmation

Relative ion abundance /% > 50 > 20 ~ 50 > 10 ~ 20 <=10 Allowable relative error /% ± 10 ± 15 ± 20 ± 50

7.5 Blank test

Except that no sample is added, the sample blank experiment is performed according to the above measurement conditions and procedures.

9.1 Limit of quantitation

The limit of quantification of this standard for rice, corn, wheat, soybeans, brown rice, pears, grapes, potatoes, cucumbers, tomatoes and mushrooms is 0.01 mg/kg; dry the limit of quantification of pepper is 0.05 mg/kg.

9.2 Recovery rate

See Table B in Appendix B for the recovery range of different substrates and different addition levels. 1.

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Appendix A

(Informative appendix) Chromatogram of Phenylfluorosulfone Standard SN/T 0491-2019 SN/T 0491-2019 Appendix B (Informative appendix) Recovery rate

Table B. 1 The concentration and recovery data of the sample

Additive amount of matrix (mg/kg) Recovery range (%) Substrate Added amount (Mg/kg) Recovery range (%) Rice 0.01 76.0-100.5 0.02 78.0-100.5 0.1 84.2-1000.4 brown rice 0.01 79.0-99.0.0 0.02 77.5-100.3 0.1 84.9-103.4 wheat 0.01 77.0-103.0 0.02 78.0-100.5 0.1 81.8-105.4 potato 0.01 79.0-100.3 0.02 80.0.5-100.5 0.1 86.9-102.2 corn 0.01 75.0-100.3 0.02 78.2-101.0.0 0.1 82.9-102.1 5 83.8-101.4 0.01 84.0-100.5 0.02 84.0-100.8 0.1 87.5-102.1 5 86.6-100.2 Soy 0.01 75.0-104.0 0.02 74.0-98.5 0.1 81.5-102.1 0.2 84.0-106.0 grape 0.01 79.0-100.3 0.02 79.5-101.0 0.1 84.4-101.4 15 85.2-100.3 tomato 0.01 79.0-107.0 0.02 81.0-100.5 0.1 84.9-103.1 2 84.0-102.5 mushroom 0.01 76.0-100.8 0.02 79.0-106.0 0.1 81.2-102.1 5 83.8-100.2 cucumber 0.01 82.0-104.0 0.02 82.5-106.0 0.1 87.4-101.2 5 87.8-100.4 Dried chili 0.05 75.0-106.0 0.1 80.9-100.5 0.5 82.0-102.0 20 81.6-100.1 SN/T 0491-2019 P. R. C.

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0.01 76.0-100.5

0.02 78.0-100.5

0.1 84.2-1000.4

0.01 79.0-99.0.0

0.02 77.5-100.3

0.1 84.9-103.4

0.01 77.0-103.0

0.02 78.0-100.5

0.1 81.8-105.4

0.01 79.0-100.3

0.02 80.0.5-100.5

0.1 86.9-102.2

0.01 75.0-100.3

0.02 78.2-101.0.0

0.1 82.9-102.1

5 83.8-101.4

0.01 84.0-100.5

0.02 84.0-100.8

0.1 87.5-102.1

5 86.6-100.2

0.01 75.0-104.0

0.02 74.0-98.5

0.1 81.5-102.1

0.2 84.0-106.0

0.01 79.0-100.3

0.02 79.5-101.0

0.1 84.4-101.4

15 85.2-100.3

0.01 79.0-107.0

0.02 81.0-100.5

0.1 84.9-103.1

2 84.0-102.5

0.01 76.0-100.8

0.02 79.0-106.0

0.1 81.2-102.1

5 83.8-100.2

0.01 82.0-104.0

0.02 82.5-106.0

0.1 87.4-101.2

5 87.8-100.4

0.05 75.0-106.0

0.1 80.9-100.5

0.5 82.0-102.0

20 81.6-100.1

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