GB 23200.12-2016Food safety national standard -- Determination of 440 pesticides and related chemical residues in edible fungi by liquid chromatography-mass spectrometry (English PDF)

4.1 Reagents

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

4.1.2 Acetone (CH3COCH3, 67-64-1). Chromatographic Purification.

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

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

4.1.5 dichloromethane (CH2Cl2, 75-09-2). chromatographic purity.

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

4.1.7 Methanol (CH3OH, 67-56-1/170082-17-4). Chromatographic Purification.

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 4h, stored in a dryer, cooling and standby.

4.2 Solution preparation

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

4.2.2 Formic acid solution (0.1%). take 1000 mL of water, add 1 mL of formic acid, shake back.

4.2.3 ammonium acetate solution (5mmol/L). Weigh 0.385 g ammonium acetate, dissolved in 1000 mL of aqueous solution, shake back.

4.2.4 acetonitrile - water solution (3 2). take 300 mL of acetonitrile, add.200 mL of water, 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

Respectively, weighing 5mg ~ 10mg (accurate to 0.1mg) pesticides and related chemicals in the standard 10mL volumetric flask, according to the standard the solubility of the quasi-solution is methanol, n-hexane, acetone, acetonitrile or isooctane dissolved and constant volume to the scale (solvent options see Appendix A). standard the stock solution is stored at 4 ° C for 1 year.

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

According to the retention time of pesticides and related chemicals, 440 kinds of pesticides and related chemicals are divided into A, B, C, D, E, F and G and the concentration of each pesticide and associated chemical in the instrument to determine the concentration in the mixed standard solution. This standard for the classification of 440 pesticide and related chemicals and their mixed standard solution concentrations, see Appendix A.

Depending on the grouping of each pesticide and associated chemical, the concentration of the standard solution and the concentration of the standard stock solution, the amount of individual Pesticide and related chemicals Standard stock solution in 100mL volumetric flask, with a fixed volume of methanol to the scale. Mixed standard solution stored at 4 ° C, the shelf life is one month.

4.4.3 Substrate mixed standard working solution

Pesticide and related chemicals Substrate mixed standard working solution is prepared by mixing the sample with different concentrations of the substrate mixed with standard working solution Liquid A, B, C, D, E, F and G are used for standard working curves. Matrix mixed standard working solution should be used with the current distribution.

4.5 Materials

4.5.1 Solid Phase Extraction Column. Sep-Pak CarbonNH2

1), 6 mL, 1 g or equivalent.

4.5.2 Microporous membrane (nylon). 13mm × 0.2µm.

7.1 Extraction

Weigh 20g sample (accurate to 0.01g) in 80mL centrifuge tube, add 40mL acetonitrile, 15000r/min homogenate extraction 1min, Add 5g sodium chloride, and then homogenate extraction 1min, 4200 r/min centrifugal 5min, take supernatant 20mL (equivalent to 10g sample volume), 40 °C Water bath rotation concentrated to about 1mL, 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 vial was washed with 2 mL of acetonitrile-toluene solution and the washings were combined into the extraction column and repeated this operation 3 times. The residual sample was transferred to an extraction column. At the top of the SPE column, connect a 50 mL reservoir with 25 mL of acetonitrile-toluene Solution elution pesticides and related chemicals, combined in 100mL chicken heart bottle, 40 °C water bath spin concentrated to 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.

About 0.5mL. And dried at 45 ° C under nitrogen. The residue was dissolved in 1 mL of acetonitrile-water solution and filtered through a 0.2 µm microporous membrane for liquid chromatography Determination of Tandem Mass Spectrometer. At the same time take no pesticide and related chemicals, edible fungus samples, according to 7.1 and 7.2 steps to prepare sample blank extract, Used to prepare matrix mixed standard working solution.

7.3 Determination

7.3.1 A, B, C, D, E, F Group Liquid Chromatography - Tandem Mass Spectrometry Reference Conditions Column.

A) ZORBAX SB-C18, 3.5 µm, 100 mm × 2.1 mm (inner diameter) or equivalent;

B) mobile phase and gradient elution conditions in Table 1;

Table 1 Mobile phase and gradient elution conditions

Total flow/min Flow rate/(µL/min) Mobile phase A (0.1% formic acid) /% Mobile phase B (acetonitrile) /% 0 0.00 400 99.0 1.0 1 3.00 400 70.0 30.0 2 6.00 400 60.0 40.0 3 9.00 400 60.0 40.0 4 15.00 400 40.0 60.0 5 19.00 400 1.0 99.0 6 23.00 400 1.0 99.0 7 23.01 400 99.0 1.0 C) Column temperature. 40 ° C;

D) Injection volume. 10 µL;

E) ionization source mode. electrospray ionization;

F) ionization source polarity. positive mode;

G) atomization gas. nitrogen;

H) atomization gas pressure. 0.28 MPa;

I) ion spray voltage. 4000 V;

J) Dry gas temperature. 350 ° C;

K) Dry gas flow rate. 10 L/min;

L) Monitor the ion pair, the collision gas energy and the source fragmentation voltage, see Appendix B.

7.3.2 Group G Liquid Chromatography - Tandem Mass Spectrometry Reference Conditions

A) Column. ZORBAX SB-C18, 3.5 µm, 100 mm × 2.1 mm (inner diameter) or equivalent;

B) mobile phase and gradient elution conditions in Table 2;

Table 2 Mobile phase and gradient elution conditions

Total time/min Flow rate/(µL/min) Mobile phase A (5 mmol/L ammonium acetate water) /% Mobile phase B (acetonitrile) /% 0 0.00 400 99.0 1.0 1 3.00 400 70.0 30.0 2 6.00 400 60.0 40.0 3 9.00 400 60.0 40.0 4 15.00 400 40.0 60.0 5 19.00 400 1.0 99.0 6 23.00 400 1.0 99.0 7 23.01 400 99.0 1.0 C) Column temperature. 40 ° C;

D) Injection volume. 10 µL;

E) ionization source mode. electrospray ionization;

F) ionization source polarity. negative mode;

G) atomization gas. nitrogen;

H) atomization gas pressure. 0.28 MPa;

I) ion spray voltage. 4000 V;

J) Dry gas temperature. 350 ° C;

K) Dry gas flow rate. 10 L/min;

L) Monitor the ion pair, the collision gas energy and the source fragmentation voltage, see Appendix B.

7.3.3 Qualitative determination

When the sample is measured under the same experimental conditions, if the retention time of the detected chromatographic peaks is consistent with the standard sample, After the background of the sample mass spectrum, the selected ions are present, and the selected ion abundance ratio is proportional to the ion abundance ratio of the standard sample (Relative abundance > 50%, allow ± 20% deviation; relative abundance > 20% to 50%, allow ± 25% deviation; relative abundance > 10% to 20%, allow ± 30% deviation; relative abundance <= 10%, allow ± 50% deviation), you can determine the presence of this sample pesticide or related chemistry Goods.

7.3.4 Quantitative determination

In this standard, liquid chromatography-tandem mass spectrometry was quantitatively determined by external standard-calibration curve method. To reduce the impact of matrix on quantitative determination, quantitative use the standard solution should be prepared using a standard solution of the matrix mixed standard solution. And to ensure that the measured samples of pesticides and related chemicals response value are within the linear range of the instrument. See Appendix C for more than 440 chromatograms for multi-reaction monitoring (MRM) for pesticides and related chemicals.

7.4 Parallel test

Perform the parallel test of the same specimen according to the above procedure.

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 F.

Appendix A

(Informative)

440 pesticides and related chemicals, English name, method Quantitative limits, grouping, solvent selection and mixing Standard solution concentration A.1 440 kinds of pesticides and related chemicals, English name, method of quantitative limit, grouping, solvent selection and mixed standard solution concentration table A.1.

Table A.1 440 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 Mixed standard dissolved Liquid concentration / (Mg/L) Group A 1 aniline spirit propham 55.00 toluene 11.00 2 isoprocarb 1.16 methanol 0.23 3, 3, 4, 4, 4, 3, 3, 3, 3, 3, 5, trimethacarb 0.16 Methanol 0.03 4 ring curmitine cycluron 0.10 methanol 0.02

5 Carbaryl 5.16 Methanol 1.03

6 Toxicant propachlor 0.16 Methanol 0.03 7 pimidazole raenzazole 0.66 methanol 0.13 8 ocher net simetryn 0.06 methanol 0.01

9 Green Valley Long monolinuron 1.80 Methanol 0.36 10 times out of phosphorus mevinphos 0.80 toluene 0.16 11 azepine aziprotryne 0.70 methanol 0.14

12 Micronautics Secbumeton 0.06 Methanol 0.01

13 Azathione Sulfonamide cyprodinil 0.36 Methanol 0.07 14 sulton buturon 4.50 methanol 0.90 15 bisacyl chloride carbetamide 1.80 methanol 0.36 16 pirimicar pirmicarb 0.08 methanol 0.02

17 Isosubicin clomazone 0.20 Methanol 0.04 18 cyanocobalt cyanazine 0.10 methanol 0.02 19 promised net prometryne 0.10 methanol 0.02