GB 23200.65-2016Food safety national standard -- Determination of Tetrafluoroether Residue in Food (English PDF)

4.1 Reagents

4.1.1 Acetone (C3H6O). Residue level.

4.1.2 acetonitrile (C2H3N). residual grade.

4.1.3 n-hexane (C6H14). residual grade.

4.1.4 sodium chloride (NaCl). 650 °C burning 4 h, placed in a dryer cooling, standby.

4.2 Solution preparation

4.2.1 Acetone-n-Hexane (3 7). Take 300 mL of acetone, add 700 mL of n-hexane and shake well.

4.3 Standards

4.3.1 Tetraconazole standard (Tetraconazole, C13H11Cl2F4N3O). purity >= 96.5%.

4.4 Standard solution preparation

4.4.1 Tetrafluorodiazole standard solution preparation. accurately weighed the amount of standard, with a small amount of acetone dissolved, and acetone prepared into thick Standard reserves of 1.0 mg/mL. According to the need to use acetone - n-hexane diluted to the appropriate concentration of standard working solution. Save on-18 °C in the refrigerator.

4.5 Materials

4.5.1 Cleanert Florisil Solid phase extraction column. 500 mg, 3 mL or equivalent.

6.1 Preparation of the sample

6.1.1 Grain

Take a representative sample volume of 500g, all with a grinding mill and passed through a 2.0 mm round hole screen. Mix, are divided into two as a test Kind, divided into a clean container, sealed, marked mark.

6.1.2 Fruit or vegetables

Take a representative sample 500g, chopped, followed by the use of food mashed the sample processed into a slurry. Mix well into a clean container Inside, sealed, marked mark.

6.1.3 Meat and meat products

Take a representative sample 500g, crushed by the mashed machine evenly, into the clean container as a sample. Sealed, marked.

6.1.4 Honey and 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 dense Close 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. Load a clean container, sealed, marked with a mark.

6.1.5 Tea

Take a representative sample of 500 g, grind all with an attritor and pass through a 2.0 mm round hole screen. Mix well and clean the clean container Inside, sealed, marked mark.

6.1.6 Nuts

Take a representative sample 500g, with the mill all grinding. Mix, are divided into two as a sample, into the clean clean capacity Inside, sealed, marked mark.

6.1.7 Aquatic products

Take a representative sample 500g, remove the sample from the sample about 1 kg, crushed by the mashed evenly, are divided into two, respectively Into a clean container as a sample. Sealed and marked.

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

6.2 Sample storage

Grain samples are stored at 0-4 ° C; fruits and vegetables and other samples are cryopreserved at -18 ° C or lower. In the sampling and sample operation in the course of the process, the sample should be prevented from being contaminated or the residue content changes.

7.1 Extraction

Weigh 10 g of sample (accurate to 0.1 g) in a 100 mL stoppered centrifuge tube, add 10 mL of water, add 50 mL of saturated Acetonitrile, homogenized high-speed homogenate extraction 2 min (soy sauce and honey only violent oscillation 10min), then add 5g of sodium chloride, severe shock Swing 10min, 3000 r/min centrifugation 10min.

7.2 Purification

7.2.1 Liquid/liquid distribution purification

Take the upper extract 20 mL (spinach, lotus root, strawberry) or 10 mL (peanuts, chicken, pork, cod, honey, chestnut, tea and soy sauce) were transferred to a 50 mL stoppered centrifuge tube, 10 mL of saturated n-hexane was added, shaken for 3 min, left to stand, and discarded Hexane phase, and then repeated with 10 mL of n-hexane, discarded n-hexane phase; the lower acetonitrile phase was collected in 100 mL concentrated bottles, Concentrated in a water bath at 40 ° C to nearly 1 mL.

7.2.2 Solid phase extraction (SPE) purification

Before use with 5mL acetone - n-hexane pre-sprayed Florisil column. The sample was poured into a column, eluted with 12 mL of acetone-n-hexane, Control flow rate less than or equal to 2 mL/min. The whole eluate was collected in a 50 mL concentrated flask and concentrated in a 40 ° C water bath to near dryness and nitrogen Dry. With acetone - n-hexane dissolved and set to 1.0 mL, gas chromatography - mass spectrometry.

7.3 Determination

7.3.1 Gas Chromatography - Mass Spectrometry Reference Conditions

A) Column. HP-5 MS quartz capillary column, 30 m × 0.25 mm (id), film thickness 0.25 µm, or equivalent;

B) column temperature. the initial temperature of 70 °C, 30 °C/min program temperature to.200 °C, keep 10min, then 50 °C/min process the temperature was raised to 270 ° C and maintained for 4 min.

C) Inlet temperature. 250 ° C;

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

E) Carrier gas. helium, purity greater than or equal to 99.999%, constant pressure mode, column head pressure 1.45Mpa);

F) Injection volume. 1 µL;

G) Injection method. no split injection, 0.65 min after the opening valve;

H) ionization mode. negative chemical ionization;

I) ion source temperature. 150 ° C;

J) quadrupole temperature. 150 ° C;

K) reactant gas. methane, purity >=99.99%;

L) Determination of the way. select the ion monitoring mode;

M) Select the monitoring ion (m/z). Quantitative 117, Qualitative 217,275,295;

N) solvent delay. 4.0 min.

7.3.2 Determination and confirmation of chromatography

According to the sample solution content of the sample, the selected concentration of similar standard working solution, the standard working solution and sample volume and other volume into the the measured values of the tetrafluoroether in the standard working solution and the sample to be measured 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, and after subtracting the background of the sample mass, the selected ions are present, the abundance of the selected ions is greater than the abundance of the corresponding ions of the standard, Within the allowable range (see Table 1). The retention time of tetrafluoroether in the condition of 7.3.1 is 19.71 min, and the monitoring ion (m/z) which was confirmed by m/z 117, 217,275,295 (the abundance ratio was 100. 38. 11. 27); according to the quantitative ion m/z117 the amount of external standard method. Gas chromatographic-mass spectrometry total ion chromatogram and full scan spectroscopy of tetrafluorodiazepine standards under 7.3.1 See Figure A.1 and Appendix B, Appendix B.1 in Appendix A.

Table 1 Maximum qualitative error of relative ion abundance when qualitative gas chromatography-mass spectrometry

Relative abundance (base) 50% 20% to 50% 10% to 20% <=10% Allowable relative deviation ± 20% ± 25% ± 30% ± 50%

10.1 Quantitation limits

The limit of quantification of the method for tetrasulfonyl ether is 2 µg/kg.

10.2 Recovery rate

When adding levels of 0.002 mg/kg, 0.004 mg/kg, 0.01 mg/kg, the recoveries of tetrafluoroether beads are given in Appendix C.

Appendix A

(Informative)

Total Ion Flow Chromatogram of Tetrafluorodiazole Standard Substance 6 .0 08.0 01 .0 01 2 .0 01 4 .0 01 6 .0 01 8 .0 02 0 .0 02 2 .0 02 4 .0 02 6 .0 0 T im e - - > A bundance TIC. 2 0 PPB .D 1 9 .7 2 Min

Figure A.1 Tetrafluorodiazole standard gas chromatography-mass spectrometry total ion chromatogram

Appendix B

(Informative)

Mass Spectrometry of Tetrafluorodiazole Standard Substance 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 S can 1 8 7 3 (1 9.77 7 in). TETRACON .D 2 5 51 4 95 7 3 2 09 7 5 1 7

Figure B.1 Tetrafluorodiazole standard substance Gas chromatography-mass spectrometry

Appendix C

(Informative)

The recovery of pesticides in different substrates

Table 1 Sample recovery rate

Sample concentration (µg/kg) Recovery rate range (%) Sample addition concentration (µg/kg) Recovery rate range (%) spinach 2 90.0 ~ 110.0 Codfish 2 90.0 ~ 110.0 4 95.0 to 107.5 4 92.5 to 107.5 10 97.0 to 112.0 10 97.0 to 119.0 2 95.0 to 110.0 honey 2 90.0 ~ 110.0 4 97.5 to 110.0 4 92.5 to 107.5 10 96.0 to 112.0 10 96.0 to 112.0 Strawberry 2 81.5 ~ 100.8 Chestnut 2 95.0 ~ 115.0 4 92.5 to 107.5 4 92.5 to 107.5 10 96.0 to 112.0 10 95.0 to 114.0 peanut 2 90.0 ~ 110.0 tea 2 90.0 ~ 110.0 4 90.0 to 112.5 4 97.5 to 112.5 10 94.0 to 117.0 10 97.0 to 113.0 chicken 2 90.0 ~ 110.0 soy sauce 2 95.0 to 110.0 4 95.0 ~ 107.5 4 92.5 ~ 115.0 10 94.0 to 112.0 10 94.0 to 115.0 pork 2 90.0 ~ 110.0

4 92.5 ~ 112.5 ----- ----10 94.0 ~ 112.0 -----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