GB 23200.5-2016Food safety national standard -- Methods for the determination of herbicide residues -- Part 5: Determination of thiocarbamate herbicides in food by liquid chromatography-mass spectrometry / mass spectrometry (English PDF)

4.1 Reagents

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

4.1.2 n-hexane (C6H14,110-54-3).

4.1.3 Acetone (C3H6O, 67-64-1).

4.1.4 acetic acid (C2H4O2, 64-19-7). chromatography pure.

4.1.5 Sodium chloride (NaCl, 7647-14-5).

4.2 Solution preparation

4.2.1 N-Hexane-Acetone Solution (7 3). Accurately measure 70 mL of n-hexane and 30 mL of acetone and shake well.

4.2.2 acetonitrile - water solution (1 1). accurate measurement of 50 mL of acetonitrile and 50 mL of water, shake back.

4.3 Standards

4.3.1 Reference material. see Appendix A, Table A.1, purity is greater than 99%.

4.3.2 Standard reference substance. D3- Carbaryl (100 µg/mL).

4.4 Standard solution preparation

4.4.1 Thiocarbamate Pesticide Standard Reserve Solution (100 µg/mL). Accurate weighing of various thiourethane standards Quality, with acetonitrile prepared into a concentration of 100 mg/L standard stock solution, protected from light -18 °C, the shelf life of 6 months.

4.4.2 Thiourethane Pesticide Mixed Standard Intermediate Solution (1.0 µg/mL). Draw each amount of standard stock solution, Release 1.0 mg/L mixed standard working solution, protected from light -18 °C, the shelf life of 1 month.

4.4.3 Internal standard solution (1.0 µg/mL). Accurately absorb the appropriate amount of standard material, with acetonitrile prepared into a concentration of 1.0 mg/L Internal standard working solution, light -18 °C preservation, shelf life of 1 month.

4.5 Materials

4.5.1 HLB solid phase extraction column or equivalent..200 mg, 6 mL. Use 5 mL of acetonitrile before treatment to keep the cylinder moist.

4.5.2 Envi-Carb solid phase extraction column or equivalent..200 mg, 3 mL. Wash with 5 mL n-hexane-acetone before use to keep the column wet Run.

4.5.3 Microporous membrane. 0.22 µm, organic phase type.

6.1 Preparation of the sample

6.1.1 Rice, soybeans, peanuts and tea leaves

Approximately 500 g of the sample was taken and pulverized thoroughly with a pulverizer. All samples were passed through a standard screen of 425 µm. Mix well. The samples are divided into two Copies, into a clean container, sealed, and marked with a mark.

6.1.2 White radish, cabbage, broccoli, ginger, oranges, grapes, chicken, and fish

Approximately 500 g of the sample was taken and it was chopped (not washed with water). The sample was processed into a slurry by a mash and mixed. Samples are Divided into two, packed into a clean container, sealed and marked with a mark.

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

6.2 Sample storage

Rice, soybeans, peanuts and tea samples kept at room temperature. White radish, cabbage, broccoli and other samples in -18 C below 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

7.1.1 Rice, soybeans, tea and peanuts

Weigh 5 g (accurate to 0.01 g) sample in 50 mL stoppered centrifuge tube, weighed 2.5 g, add 100 µL internal standard intermediate solution, Add 10 mL of water, mix and place for 1 h. Then add 4.0 g of sodium chloride, then add 15 mL of acetonitrile high-speed homogeneous extraction 3 min, the oscillation to mention Take 15 min and centrifuge at 5 000 r/min for 5 min, transfer the acetonitrile layer to a 25 mL volumetric flask. The residue was again extracted with 10 mL of acetonitrile the combined extracts were combined and bound to 25 mL with acetonitrile.

7.1.2 White radish, cabbage, broccoli, ginger, oranges, grapes, chicken, and fish

Weigh 5 g (accurate to 0.01 g) sample in a 50 mL stoppered centrifuge tube, add 100 µL of the internal standard solution and 4.0 g of sodium chloride, the following operation is the same as 7.1.1.

7.2 Purification

7.2.1 Rice, white radish, cabbage, broccoli, ginger, oranges, grapes, chicken and fish

Take 5.0 mL of the extract in 15 mL centrifuge tube, 40 °C with N2 blowing to near dry. The residue was dissolved in 2.0 mL of n-hexane-acetone solution the solution was added to the treated Envi-Carb solid phase extraction column and the sample solution was passed through a solid phase extraction column at a flow rate of about 1.5 mL/min.

The sample tubes were rinsed with 5 mL of n-hexane-acetone solution and the rinsing solution was added to the Envi-Carb solid phase extraction column to collect the total effluent in 15 ML centrifuge tube, 40 °C blowing nitrogen to near dry. The residue was fixed to 1.0 mL with acetonitrile-water solution. After vortexing, the residue was passed through a microfiltration membrane Determination by GC - MS.

7.2.2 Soybean, tea, peanuts and chicken liver

Take 5.0 mL extract in 15 mL centrifuge tube, tea extract to take 10.0 mL, 40 °C with N2 to 2.0 mL or so. will the concentrate was transferred to a treated HLB solid phase extraction column, and the sample solution was passed through a solid phase extraction column at a flow rate of about 1.5 mL/min, ML of acetonitrile was rinsed and the solid phase extraction column was drained. The whole effluent was collected in a 15 mL centrifuge tube and purged with N2 at 40 ° C.

The residue was dissolved in 2.0 mL of n-hexane-acetone solution and the solution was added to the treated Envi-Carb solid phase extraction column at about 1.5 ML/min. The sample solution was passed through a solid phase extraction column and the sample tube was rinsed with 5 mL of n-hexane-acetone solution and the rinsing solution was added the Envi-Carb solid phase extraction column was collected and the whole effluent was collected in a 15 mL centrifuge tube and the nitrogen was blown at 40 ° C to near dryness. The residue was eluted with acetonitrile - water to 1.0 mL, vortex after mixing, through the microporous membrane, for liquid chromatography - mass spectrometry.

7.3 Determination

7.3.1 Liquid Chromatographic Reference Conditions

A) Column. Acquity BEH C18 column, 50 mm × 2.1 mm (id), 1.7 µm, or equivalent;

B) Column temperature. 40 ° C;

C) Injection volume. 10 µL;

D) The mobile phase, flow rate and gradient elution conditions are shown in Table 1.

Table 1 Mobile phase, flow rate and gradient elution conditions

time

Min

Flow rate

ML/min

0.1% acetic acid aqueous solution Methanol 0 0.25 70 30 15.0 0.25 0 100 15.1 0.25 70 30 18.0 0.25 70 30

7.3.2 Mass spectrometry reference conditions

A) ionization mode. electrospray ion source;

B) Scanning mode. positive ion scanning;

C) Detection method. Multiple reaction monitoring (MRM);

D) Resolution. Unit resolution;

See Appendix B for other reference mass spectrometry conditions.

7.4 Standard working curve

(1.0 µg/mL) and the internal standard solution (1.0 µg/mL) were mixed with a blank sample extraction solution 10 µg/L, 100 µg/L, 100 µg/L, 100 µg/L, 100 µg/L, 100 µg/L, Quasi-working solution, the internal standard concentration of 20.0 µg/L. Preparation for use, for liquid chromatography - mass spectrometry. To be measured and internal standard Peak area ratio of the ordinate, matrix mixed standard working solution concentration for the abscissa to draw the standard working curve.

7.5 Determination

7.5.1 Qualitative determination

Each selected component selected one parent ion, two or more child ions, in the above experimental conditions, the sample retention time of the material to be tested, and the substrate standard solution retention time deviation within ± 2.5%; and the sample of each component of the relative abundance of ions and concentrations close to the matrix Comparing the relative abundance of the corresponding qualitative ions in the standard working solution, the deviation does not exceed the range specified in Table 2, There is a corresponding test substance in the product.

Table 2 The maximum allowable deviation of relative ion abundance when qualitative confirmation

Relative ion abundance > 50% > 20% to 50% > 10% to 20% <=10% Maximum permissible deviation ± 20% ± 25% ± 30% ± 50%

7.5.2 Quantitative determination

In the best working conditions of the instrument, the standard solution of the mixed working solution of the matrix was measured with the ratio of the peak area of the analyte and the internal standard, Matrix mixed standard working solution concentration for the abscissa to draw the standard working curve, with the standard working curve of the sample quantitative, sample solution the response value of the test object should be within the linear range of the instrument; if the linear range is exceeded, the blank matrix solution is used for proper dilution Injection assay. A multi-reaction monitoring (MRM) chromatogram of the nine thiocarbamate herbicide reference materials is shown in Figure C.1 in Appendix C.

7.6 Blank experiment

In addition to the standard sample, according to the above measurement steps.

10.1 Quantitation limits

The limit of quantification for nine thiocarbamate herbicides was 5.0 µg/kg.

10.2 Recovery rate

In the range of 5.0 µg/kg ~.200 µg/kg, add rice, soybeans, white radish, cabbage, broccoli, ginger, tea, flower the recovery rates of nine thiocarbamate herbicides in raw, orange, grape, chicken, and fish are shown in Appendix D.

Appendix A

(Informative)

Table A.1 Information on 9 thiocarbamate herbicides

Compound English name CAS No. Molecular formula Cobalt pebulate 1114-71-2 C10H21NOS Grasses of molybdenum Green grass enemy EPTC 759-94-4 C9H19NOS Cotyledon thiobencarb 28249-77-6 C12H16ClNOS Oat enemy Butterone Wild tartan triallate 2303-17-5 C10H16Cl3NOS Cedar enemies vernolate 1929-77-7 C10H21NOS Cyclocane Cycloxy 1134-23-2 C11H21NOS Appendix B (Informative) Reference to mass spectrometry conditions A) electrospray voltage. 3000 V;

B) Auxiliary gas flow rate. 700 L/h;

C) collision gas. argon;

D) curtain air flow rate. 50 L/h;

E) ion source temperature. 105 ° C;

F) Auxiliary gas temperature. 350 ° C;

G) Qualitative ion pair, quantitative ion pair, acquisition time, extraction voltage and collision energy are shown in Table B.1.

Table B.1 Mass spectrometric parameters for the determination of 9 thiocarbamate herbicides

Analyte

Reference retention time Min Parent ion Acquisition time Extraction voltage Collision energy EV Grasshopper 7.20 188 126 * 0.10 32 Rhizoctonia enemy 8.57 190 128 * 0.05 28 Bitter enemy 10.56 218 57 * 0.05 32 Destroy the enemy 9.79 204 86 * 0.05 30 the enemy is 9.84 204 57 * 0.05 28 Wild pills 11.62 306 86 * 0.05 30 Grasses 9.77 258 100 * 0.05 28 Ring grass enemy 9.89 216 154 * 0.05 24 Ophiopogon 10.30 270 86 * 0.05 34 D3- Carbaryl 4.22 205 145 * 0.05 20 10 Note. * for the quantitative ions, for different mass spectrometry equipment, instrument parameters may be different, should be measured before the mass spectrometry parameters to optimize the best.

Non-commercial statement. The reference mass spectrometry conditions listed in Appendix A are performed on a Waters Quattro Premier LC/MS.

The list of test instruments listed below is for reference only and does not involve commercial purposes and encourages standard users to try different manufacturers or models of instruments.

Appendix C

(Informative)

Standard multi-reaction monitoring (MRM) chromatograms

Figure C.1 5.0 µg/L 9 Thiocarbamate Herbicides Standard Solution Multiple Reaction Monitoring (MRM) Chromatogram

Appendix D

(Informative)

The recovery of nine thiocarbamate pesticides in different substrates

Table D.1 Experimental data on the concentration and recovery of the sample

The name of the compound Add level Mg/kg Rice Recovery rate Soybeans Recovery rate range White radish Recovery rate Cabbage Recovery rate Broccoli Recovery rate Ginger Recovery rate range orange Recovery rate range grape Recovery rate range peanut Recovery rate range tea Recovery rate range chicken Recovery rate range Chicken liver Recovery rate Fish Recovery rate Grass enemies 5.0 83.3 to 99.1 73.6 to 95.6 61.5 to 79.7 76.1 to 92.7 66.0 to 84.0 66.1 to 80.1 73.4 to 86.6 80.4 to 95.4 75.1 to 97.5 75.9 to 93.2 80.9 to 91.1 69.8 to 88.5 77.1 to 90.4 10.0 88.3 to 104 72.2 to 87.2 64.4 to 78.4 67.1 to 79.2 66.3 to 84.3 65.4 to 79.8 68.9 to 83.5 77.5 to 93.2 73.6 to 88.9 70.8 to 85.0 73.6 to 90.2 74.2 to 91.8 70.2 to 86.0 20.0 81.7 to 91.5 70.3 to 85.5 65.8 to 83.6 77.6 to 97.5 79.5 to 93.5 68.5 to 82.6 74.2 to 82.8 80.0 to 85.8 71.7 to 87.2 68.5 to 83.4 70.4 to 85.3 74.7 to 92.4 67.1 to 81.3 Rice. 100 Soybeans, white radish, cabbage, Broccoli, ginger, oranges, grapes, Tea, peanuts, chicken, liver, Fish. 50.0 84.3 to 95.1 75.4 to 89.6 71.6 to 90.2 81.2 to 89.8 82.4 to 96.4 69.6 to 81.8 67.2 to 83.8 80.6 to 88.6 76.9 to 91.4 73.5 to 87.4 71.2 to 87.8 76.4 to 87.0 67.9 to 83.7 Mussel enemy 5.0 87.2 to 104 70.9 to 85.8 63.0 to 79.3 74.2 to 88.2 63.2 to 79.8 68.1 to 78.0 74.2 to 89.9 66.3 to 90.3 73.7 to 89.2 69.1 to 83.7 90.6 to 99.5 67.6 to 85.2 86.4 to 94.9 10.0 82.3 to 94.4 69.1 to 86.1 67.8 to 81.9 77.4 to 94.6 65.5 to 77.8 68.3 to 86.3 78.5 to 96.6 76.7 to 89.3 71.9 to 89.5 67.4 to 83.9 71.5 to 92.7 62.2 to 77.9 68.2 to 88.4 20.0 71.2 to 79.1 68.6 to 78.4 65.2 to 80.5 87.4 to 101 67.6 to 78.6 79.2 to 93.8 77.9 to 97.8 68.6 to 80.2 71.3 to 81.5 67.8 to 76.4 76.1 to 87.3 74.4 to 93.3 72.6 to 83.2 Rice, soybeans, white radish, small Cabbage, broccoli, ginger, oranges, Grapes, peanuts, Chicken, liver, fish. 50.0 68.5 to 76.9 68.5 to 76.9 68.5 to 85.1 88.2 to 99.8 68.5 to 80.5 78.5 to 90.8 80.9 to 92.1 69.1 to 82.1 71.2 to 80.0 66.8 to 75.0 77.8 to 88.2 71.6 to 86.2 74.2 to 84.1 Grams of grass enemy 5.0 94.9 to 112 79.9 to 88.2 70.0 to 83.2 66.1 to 82.5 71.5 to 80.4 70.8 to 88.6 67.6 to 92.1 71.6 to 99.9 83.1 to 92.1 77.9 to 86.4 80.2 to 97.0 71.0 to 81.2 76.5 to 92.5 10.0 87.3 to 107 72.8 to 86.6 64.1 to 82.0 67.3 to 80.1 63.2 to 79.7 70.4 to 79.6 68.9 to 89.5 70.4 to 92.2 75.7 to 90.1 71.0 to 84.4 71.2 to 88.4 68.2 to 86.4 67.9 to 84.3 20.0 87.0 to 92.6 74.5 to 84.2 74.9 to 85.8 84.4 to 99.1 71.0 to 82.0 70.0 to 75.7 76.8 to 91.9 70.9 to 81.6 77.5 to 87.6 72.6 to 82.1 71.4 to 87.7 75.3 to 85.8 68.1 to 83.6 100 73.9 to 82.6 73.9 to 82.6 76.2 to 88.4 88.3 to 98.2 72.5 to 81.9 74.6 to 82.1 83.1 to 95.4 74.2 to 84.3 76.9 to 85.9 72.1 to 80.5 73.4 to 86.1 77.3 to 86.1 70.0 to 82.1 Destroy the enemy 5.0 96.8 to 112 74.6 to 93.3 72.2 to 89.9 71.8 to 94.0 72.2 to 81.9 68.1 to 83.1 67.4 to 92.8 80.5 to 98.7 77.2 to 96.6 72.7 to 91.0 78.4 to 89.6 71.7 to 89.8 74.7 to 85.4 10.0 86.7 to 105 73.3 to 83.6 67.2 to 79.0 68.5 to 79.2 71.2 to 78.5 65.9 to 79.7 80.6 to 95.3 67.8 to 91.1 75.9 to 89.1 71.5 to 83.9 70.6 to 86.9 70.3 to 90.5 67.3 to 79.3 20.0 82.0 to 90.6 70.0 to 81.5 72.4 to 85.1 79.4 to 92.5 69.0 to 82.9 70.3 to 78.9 75.4 to 90.1 69.4 to 90.6 72.5 to 84.4 68.3 to 79.5 70.9 to 84.4 75.9 to 92.4 67.6 to 80.5 100 70.5 to 82.1 70.5 to 82.1 75.4 to 88.3 80.2 to 95.4 70.8 to 83.2 70.9 to 83.1 76.8 to 92.3 74.2 to 90.5 73.0 to 84.1 68.7 to 80.0 72.5 to 86.1 76.9 to 91.5 69.1 to 82.1 Ring grass enemy 5.0 106 to 119 67.0 to 87.6 70.4 to 88.2 68.1 to 89.1 68.3 to 85.6 72.0 to 80.2 62.2 to 81.7 81.1 to 103 75.7 to 91.2 65.3 to 85.4 77.0 to 92.8 78.7 to 94.5 73.4 to 88.5 10.0 102 to 119 75.7 to 94.6 74.7 to 89.4 65.8 to 80.4 67.1 to 86.6 72.8 to 87.2 79.5 to 104 83.6 to 99.9 78.8 to 98.5 73.8 to 92.2 71.8 to 90.2 82.9 to 98.8 68.5 to 86.0 20.0 96.1 to 103 80.8 to 91.6 83.2 to 99.0 80.6 to 94.3 68.8 to 74.4 70.6 to 78.7 70.9 to 88.4 78.9 to 91.8 84.1 to 95.4 78.8 to 89.3 75.5 to 91.1 78.2 to 93.9 72.0 to 86.9 50.0 82.4 to 96.6 82.4 to 96.6 86.6 to 98.2 79.8 to 94.6 69.8 to 82.4 72.2 to 85.8 73.0 to 89.2 76.4 to 90.6 85.8 to 101 80.3 to 94.2 78.2 to 93.8 84.0 to 97.2 74.6 to 87.9 grass Dan 5.0 101 to 113 78.7 to 97.0 85.6 to 99.4 76.8 to 92.0 74.5 to 85.1 76.0 to 81.6 69.6 to 91.8 83.8 to 105 81.5 to 100 76.7 to 94.6 77.7 to 94.3 102 to 113 74.1 to 89.9 10.0 103 to 113 79.7 to 92.0 95.2 to 99.0 79.7 to 87.6 75.7 to 87.8 79.4 to 84.0 85.6 to 100 89.4 to 96.7 82.6 to 95.3 77.7 to 89.7 72.3 to 92.0 93.3 to 106 68.9 to 87.7 20.0 95.1 to 102 80.1 to 93.0 82.2 to 101 80.1 to 100 93.5 to 99.6 82.5 to 88.6 82.2 to 98.5 85.8 to 94.7 83.0 to 96.3 78.1 to 90.7 81.9 to 101 98.3 to 114 78.1 to 96.2 200 81.4 to 92.0 81.4 to 92.0 90.5 to 100 81.0 to 96.0 90.5 to 99.5 81.5 to 91.0 82.0 to 96.5 89.5 to 97.0 84.3 to 95.3 79.4 to 89.7 82.0 to 98.0 97.5 to 109 78.2 to 93.4 Oat enemy 5.0 102 to 111 66.5 to 83.6 73.1 to 87.7 68.9 to 82.8 70.5 to 82.4 64.6 to 78.8 63.4 to 81.6 85.4 to 110 68.4 to 85.9 64.8 to 81.5 72.2 to 90.2 90.3 to 98.4 68.8 to 86.0 10.0 83.6 to 98.96 73.3 to 86.9 69.6 to 80.3 68.8 to 80.9 65.3 to 78.7 75.7 to 86.9 73.7 to 96.0 85.5 to 100 75.4 to 89.3 71.5 to 84.7 77.9 to 93.2 83.3 to 94.5 74.3 to 88.9 20.0 87.7 to 104 77.1 to 93.2 84.5 to 101 83.7 to 97.4 71.2 to 82.4 75.2 to 83.6 74.8 to 91.5 82.2 to 93.5 79.3 to 95.8 75.2 to 90.9 75.4 to 88.5 80.7 to 91.6 71.9 to 84.4 Rice, soybeans, white radish, small Cabbage, broccoli, ginger, oranges, Grapes, peanuts, chicken, fish.

50.0

Tea. 100

Chicken liver..200

79.2 to 93.8 79.2 to 93.8 88.6 to 100 82.6 to 95.6 71.6 to 89.2 77.4 to 90.0 72.2 to 91.2 82.4 to 92.6 81.4 to 96.4 77.2 to 91.5 76.8 to 90.2 81.0 to 91.5 73.2 to 86.0 Wild wailing 5.0 89.6 ~ 109 67.6 ~ 86.6 69.9 ~ 86.1 84.4 ~ 99.67 3.3 67.2 to 80.6 68.2 to 88.7 72.0 to 87.8 77.6 to 102 69.4 to 88.9 65.9 to 84.4 70.4 to 86.0 69.1 to 86.6 67.1 to 84.5 10.0 95.4 to 116 76.9 to 89.6 65.0 to 78.2 73.3 to 81.66 68.1 to 76.3 75.9 to 88.8 71.0 to 87.3 83.5 to 96.9 79.0 to 92.0 75.0 to 87.4 70.8 to 82.8 86.4 to 106 67.5 to 78.9 20.0 95.5 to 109 70.1 to 88.6 80.1 to 95.6 77.8 to 93.7 84.1 to 89.0 79.3 to 88.4 77.0 to 93.6 83.2 to 90.0 72.0 to 88.6 73.2 to 86.4 77.9 to 99.4 81.0 to 91.3 74.3 to 94.8 Rice, soybeans, peanuts. 50.0 White radish, cabbage, broccoli, Ginger, oranges, tea, grapes, Chicken, fish. 100 Chicken liver..200 74.2 to 88.6 73.6 to 88.6 82.4 to 96.1 79.2 to 93.5 85.1 to 91.3 80.6 to 89.1 81.0 to 92.1 81.7 to 91.3 76.2 to 91.0 71.8 to 86.4 81.9 to 94.5 81.5 to 92.0 78.1 to 90.1 Butterfly enemy 5.0 90.0 to 109 70.6 to 84.6 69.7 to 85.1 70.0 to 89.7 66.5 to 80.5 66.3 to 79.3 67.8 to 86.4 79.5 to 101 72.7 to 81.0 70.1 to 82.5 72.2 to 94.1 65.0 to 75.0 68.8 to 88.2 10.0 88.8 to 103 68.6 to 81.7 70.9 to 79.6 68.5 to 88.0 72.0 to 84.8 68.7 to 83.3 78.2 to 97.1 78.8 to 89.1 70.7 to 84.2 66.9 to 79.7 70.8 to 87.4 68.4 to 77.9 67.5 to 83.3 20.0 84.1 to 91.7 70.3 to 85.8 69.6 to 85.0 81.8 to 96.1 68.4 to 80.5 66.0 to 80.7 75.9 to 86.9 72.5 to 87.2 72.4 to 88.4 68.5 to 83.7 75.1 to 80.6 71.0 to 86.8 70.6 to 76.8 73 73 ~ Appendix E (Normative appendix) Laboratory repeatability requirements

Table E.1 Laboratory repeatability requirements

Measured component content Mg/kg Precision <=0.001 36 > 0.01 > 1 14 Appendix F (Normative appendix) Inter-laboratory reproducibility requirements

Table F.1 Inter-laboratory reproducibility requirements

Measured component content Mg/kg Precision <=0.001 54 > 0.01