AOAC Final Action Methods in 2018

MS/MS, with LODs ≤100 μg/kg for the GC-MS method. There are, however, 133 pesticides that can be analyzed by GC-MS and 200 by LC-MS/MS, with LODs ≤10 μg/kg. A. Principle Test samples are extracted with acetonitrile using a homogenizer, and the extracts are cleaned up with Cleanert TPT (Agela Technologies, Tianjin, China), EnviCarb/PSA or ECPSACB506 (UCT, Bristol, PA, USA), BE Carbon 500 g/PSA (Agilent Technologies, Santa Clara, CA, USA), or InerSep GC/PSA (GL Sciences, Tokyo, Japan), or equivalent cartridges. The pesticides are eluted with acetonitrile–toluene (3 + 1, v/v), concentrated, dried, dissolved in the recommended solution, and analyzed by GC-MS, GC-MS/MS, or LC-MS/MS. Quantification is with a matrix-matched standard calibration curve. B. Reagents (a) Solvents .—Acetonitrile, toluene, and n -hexane (HPLC grade). (b)  Acetonitrile–toluene.— 3 + 1 (v/v). (c)  Ultrapure water .—Obtained from a Milli-RO plus system together with a Milli-Q system (EMD Millipore Corp., Billerica, MA, USA). (d)  Anhydrous sodium sulfate .—Analytically pure. Baked at 650°C for 4 h and stored in a desiccator. C. Materials (a)  SPE cartridges .—Cleanert TPT (2000 mg, 12 mL; Agela Technologies), or EnviCarb/PSA (500 mg/500 mg, 6 mL; Supelco, Bellefonte, PA, USA), or equivalent. (b)  SPE tube adapter .—For 12 mL SPE tubes (57267), for 6 mL SPE tubes (57020-U; Sigma-Aldrich Shanghai Trading Co., Ltd, Shanghai, China), or equivalent. (c)  Disposable flow control valve liners .—For Visiprep TM-DL (57059; Sigma-Aldrich Shanghai Trading Co., Ltd). (d)  Pear-shaped flask .—80 mL (Z680346-1EA; Sigma-Aldrich Shanghai Trading Co., Ltd), or equivalent. See Figure  2014.09 . (e)  Reservoir .—30 mL (A82030; Agela), or equivalent. See Figure 2014.09 . (f)  Centrifuge tube .—80 mL.

AOAC Official Method 2014.09 Determination and Confirmation of Residues of 653 Multiclass Pesticides

and Chemical Pollutants in Tea GC-MS, GC-MS/MS, and LC-MS/MS

First Action 2014 Final Action 2018

Forty representative pesticides were selected based on guidance from the AOAC Method-Centric Committee on Pesticide Residues to conduct a multilaboratory validation study of the single- laboratory validated (SLV) method using two representative brands of tea. The representative pesticides selected for the multilaboratory validation study of the SLV method are as follows: 2,4′-DDE, 4,4′- DDE, benalaxyl, bifenthrin, bromophos-ethyl, bromopropylate, chlorfenapyr, diflufenican, dimethenamid, fenchlorphos, picoxystrobin, pirimicarb, pirimiphos-methyl, procymidone, propyzamide, pyrimethanil, quinoxyfen, tefluthrin, tolclofos- methyl, and trifluralin by GC-MS and GC-MS/MS; and acetochlor, benalaxyl, bensulide, butralin, chlorpyrifos, clomazone, diazinon, ethoprophos, flutolanil, imidacloprid, indoxacarb, kresoxim- methyl, monolinuron, picoxystrobin, pirimiphos-methyl, propoxur, quinoxyfen, tebufenpyrad, triadimefon, and trifloxystrobin by LC- MS/MS. LOQs for the 653 pesticides included in the SLV ranged from 0.03 to 1210 μg/kg. LODs of the GC-MS method ranged from 1.0 to 500 μg/kg, and the corresponding LOQs ranged from 2.0 to 1000 μg/kg. LODs of the GC-MS/MS method ranged from 1.0 to 900 μg/kg, and the corresponding LOQs ranged from 2.0 to 1800 μg/kg. LODs of the LC-MS/MS method ranged from 0.03 to 4820 μg/kg, and the corresponding LOQs ranged from 0.06 to 9640 μg/kg. A total of 482 of the 653 pesticides can be analyzed by GC-MS and GC-MS/MS, while 417 of the 653 pesticides can be analyzed by LC-MS/MS with LODs ≤100 μg/kg. There are 264 out of the 653 pesticides that can be analyzed by GC-MS, and 325 out of 653 by LC-MS/MS with LODs ≤10 μg/kg. There are 270 pesticides that can be analyzed by both GC-MS and LC-MS/MS. Of these, there are 264 pesticides that can be analyzed by GC-MS and 247 by LC-

Figure 2014.09. SPE equipment.

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