GB 23200.15-2016Food safety national standard -- Determination of residues of 503 pesticides and related chemicals in edible fungi by gas chromatography-mass spectrometry (English PDF)

4.1 Reagents

4.1.1 Acetonitrile (CH3CN, 75-05-8). Chromatographic Purification.

4.1.2 Toluene (C7H8, 108-88-3). Chromatographic pure.

4.1.3 n-hexane (C6H14,110-54-3). pure chromatography.

4.1.4 Acetone (CH3COCH3, 67-64-1). Chromatographic pure.

4.1.5 Cyclohexane (C6H12,110-82-7). Chromatographic Purification.

4.1.6 Isooctane (C8H18,540-84-1). Chromatographic pure.

4.1.7 Ethyl acetate (CH3COOCH2CH3,141-78-6). Chromatographic purity.

4.1.8 sodium chloride (NaCl, 7647-14-5). excellent grade pure.

4.1.9 anhydrous sodium sulfate (Na2SO4,7757-82-6). analytical grade. 650 °C burning 4 h, stored in a dryer, cooling and standby.

4.2 Solution preparation

Acetonitrile-toluene solution (3 1). take 300 mL of acetonitrile, add 100 mL of toluene, shake back.

4.3 Standards

Pesticide and Related Chemical Reference Material. Purity >=95%, see Appendix A.

4.4 Standard solution preparation

4.4.1 Standard stock solution

Accurately weigh 5 mg to 10 mg (accurate to 0.1 mg) Pesticides and related chemicals are placed in 10 mL volumetric flask, root According to the solubility of the standard and the need for determination of toluene, acetone mixture, dichloromethane and other solvents dissolved and constant volume to the scale (solvent Choose see Appendix A). The standard stock solution is stored at 4 ° C for 1 year.

4.4.2 Internal standard solution

Accurately weighed 3.5 mg epoxy heptachlor in 100 mL volumetric flask, with toluene volume to the scale.

4.4.3 Mixing standard solutions (mixed standard solutions A, B, C, D, E and F)

According to the nature and retention time of pesticides and related chemicals, 503 pesticides and related chemicals are divided into A, B, C, D, E, F Six groups and determine their concentration in the mixed standard solution based on the response sensitivity of each pesticide and associated chemical on the instrument. This standard refer to Appendix A for the grouping of 503 pesticides and related chemicals and their mixed standard solution concentrations.

Depending on the group number of each pesticide and associated chemical, the concentration of the standard solution and the concentration of the standard stock solution, Pesticide and related chemicals standard stock solution in 100 mL volumetric flask, with toluene volume to the scale. Mix the standard solution in the dark at 4 °C Save, save for a month.

4.4.4 Substrate mixed standard working solution

A, B, C, D, E, F group of pesticides and related chemical matrix mixed standard working solution is 40 µL internal standard solution and a certain volume the mixed standard solutions of A, B, C, D, E and F were added to 1.0 mL of the sample blank matrix extract respectively, Standard working solutions A, B, C, D, E and F. Matrix mixed standard working solution should be used with the current distribution.

4.5 Materials

Sep-Pak CarbonNH2

1) solid phase extraction column. 6 mL, 1 g or equivalent.

5.6 Chicken heart bottle. 100 mL

5.7 Pipettes. 1 mL and 10 mL.

5.8 Rotary evaporator.

5.9 Vials. 2 mL, with Teflon capping.

7.1 Extraction

Weigh 20 g of sample (accurate to 0.01 g) in 80 mL centrifuge tube, add 40 mL of acetonitrile, 1 5000 r/min homogenate extraction 1 min, Add 5 g sodium chloride, and then homogenate extraction 1 min, at 4.200 r/min under the conditions of centrifugation 5 min, take the supernatant 20 mL (equivalent to 10 g Sample volume), 40 °C water bath rotation concentrated to about 1 mL, to be purified.

7.2 Purification

Add about 2 cm high anhydrous sodium sulfate to the Sep-Pak CarbonNH2 solid phase extraction column and place the solid phase extraction unit on. The column was pre-washed with 4 mL of acetonitrile-toluene solution before loading, and the sample concentrate was rapidly transferred when the liquid level reached the top of anhydrous sodium sulfate to the purification column, and replace the heart of the bottle to receive. The residual sample was transferred to the extraction column with 2 mL of acetonitrile-toluene solution Times. A 50 mL reservoir was connected to the top of the SPE column and the pesticide and related chemicals were eluted with 25 mL of acetonitrile-toluene solution.

100mL chicken heart bottle, 40 °C water bath spin concentrated to about 0.5 mL. Add 5 mL of n-hexane for solvent exchange and repeat twice. set Volume of about 1 mL, add 40 µL internal standard solution, mix, for gas chromatography - mass spectrometry.

Sep-Pak CarbonNH2 solid phase extraction column is the product name of Waters' products. This information is provided for the convenience of users of this standard and does not indicate the recognition of the product. If it is His equivalent product has the same effect, you can use these equivalent.

At the same time take no pesticide and related chemicals, edible fungus samples, according to the above steps to prepare sample blank extract for the preparation of matrix mixing Standard working solution.

7.3 Determination

7.3.1 Gas Chromatography - Mass Spectrometry Reference Conditions

A) Column. DB-1701 (14% cyanopropyl-phenyl) -methylpolysiloxane, 30 m x 0.25 mm x 0.25 µm, quartz capillary column or quite;

B) Column temperature. 40 °C for 1 min, then 30 °C/min program temperature to 130 °C, then 5 °C/min temperature to 250 °C, and then to 10 °C/min temperature to 300 °C, keep 5 min;

C) Carrier gas. helium, purity >=99.999%, flow rate, 1.2 mL/min;

D) Inlet temperature. 290 ° C;

E) Injection volume. 1 µL;

F) Injection method. no split injection, 1.5 min after opening the valve;

G) electron bombardment source. 70 eV;

H) ion source temperature. 230 ° C;

I) GC-MS interface temperature. 280 ° C;

J) solvent delay. 8.30min in group A, 7.80min in group B, 7.30min in group C, 5.50min in group D, 6.10min in group E, 5.50min in group F, K) Select the ion monitoring. each compound selected a quantitative ion, 2 ~ 3 qualitative ions. Each group needs to be tested Ions in accordance with the peak sequence, respectively, sub-time detection. The retention time of each compound, the quantitative ion, the qualitative ion and the quantitative ion for the abundance ratio of qualitative ions, see Appendix B. Refer to Appendix C for the start time and dwell time of each group to detect ions.

7.3.2 Qualitative determination

When the sample is measured, if the retention time of the detected peaks is consistent with the standard sample, and after the background mass in the figure, the selected ions are present, and the selected ion abundance ratio is consistent with the ion abundance ratio of the standard sample (relative abundance > 50% Allow ± 10% deviation; relative abundance > 20% to 50% allow ± 15% deviation; relative abundance > 10% to 20% allow ± 20% deviation;

Relative abundance <= 10%, allowing ± 50% deviation), you can determine the presence of this pesticide or related chemicals in the sample. If it can not be confirmed, should be heavy New injection, in scanning mode (with sufficient sensitivity) or by adding other confirmed ions or with other higher sensitivity analytical instruments to confirm.

7.3.3 Quantitative determination

This standard uses the internal standard method of single ion quantitative determination. The internal standard is epoxy heptachlor. To reduce the impact of the matrix, quantitative standards should be used Quality sample solution mixed with standard working solution. The concentration of the standard solution should be close to the concentration of the compound to be tested. The standard A, B, C, D, E, F Six groups of reference substances Select the ion monitoring GC-MS diagram in the mushroom matrix See Appendix D.

7.4 Parallel test

Perform the parallel test of the same sample according to the above steps.

7.5 Blank test

Unless the sample is not weighed, according to the above steps.

10.1 Quantitation limits

The quantitative limits of this method are given in Appendix A.

10.2 Recovery rate

When adding levels of LOQ, 4 × LOQ, add the recovery rate see Appendix G.

Appendix A

(Informative)

503 kinds of pesticides and related chemicals, English name, method of quantitative limit, grouping, solvent selection and mixed standard solution concentration A.1 503 kinds of pesticides and related chemicals, English name, method of quantitative limit, grouping, solvent selection and mixed standard solution concentration See Table A.1

Table A.1 503 kinds of pesticides and related chemicals, English name, method of quantitative limit, grouping, solvent selection and mixed standard solution concentration

Serial number Chinese name English name the limit of quantitation/(Mg/kg) Solvent Mix the standard solution Concentration/(mg/L) Group A 1 diacetophenanthrene allidochlor 0.0250 toluene 5.00 2 soil bacteria el etantiazol 0.0376 toluene 7.50

3 Chloromethylthiophosphate chlormephos 0.0250 Toluene 5.00

4 Aniline Ling propham 0.0126 Toluene 2.50 5 ring grass enemy cycloate 0.0126 toluene 2.50 Benzene diamine a diphenylamine 0.0126 Toluene 2.50 7 chlordimeform 0.0126 n-hexane 2.50

8 Ethylene Bromine Ethalfluralin 0.0500 Toluene 10.00 9 phorate 0.0126 toluene 2.50

10 Methyl ethyl phiophosphate thiometon 0.0126 Toluene 2.50

11 Pentachloronitrobenzene quintozene 0.0250 Toluene 5.00

12 Deethyl Etrazine a atrazine-desethyl 0.0126 Toluene Acetone (8 2) 2.50

13 Isosubin pine clomazone 0.0126 Toluene 2.50 14 diazinon 0.0126 toluene 2.50

15 Diposulfuron fonofos 0.0126 Toluene 2.50 16 pyrimethazine etrimfos 0.0126 toluene 2.50

17 Amipropion propetamphos 0.0126 Toluene 2.50 18 sec. Sec. Secancourton 0.0126 Toluene 2.50

19 Acetyl Acetate pronamide 0.0126 Toluene Acetone (9 1) 2.50

20 Removal of phosphorus dichlofenthion 0.0126 Toluene 2.50 21 zyke mexacarbate 0.0376 Toluene 7.50 22 dimethoate 0.0500 Toluene 10.00

23 Amificin dinitramine 0.0500 Toluene 10.00 24 aldrin 0.0250 toluene 5.00

25 Flies Phosphorus ronnel 0.0250 Toluene 5.00 26 promised net prometryne 0.0126 toluene 2.50