Phenanthrene d10

BD Bacto dehydrated agar, salts to make M9 buffer (monobasic potassium phosphate, dibasic sodium phosphate, sodium chloride, and magnesium sulfate), 1N sodium hydroxide, p, p’-DDT (> 95%), dimethyl sulfoxide (DMSO, 99.9%), acetone (99.8%, HPLC grade), n-hexane (> = 99%), dichloromethane (99.8%, HPLC grade), sodium azide (99%), and 2-butanone (≥ 99.0%) were purchased from Fisher Scientific (Waltham, MA). Carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone (FCCP, > 98%) was purchased from Sigma-Aldrich (St. Louis, MO). Certified reference standards for gas chromatography (GC)-HRMS quantification were purchased from Accustandard (New Haven, CT), including o, p’-DDT, p, p’-DDT, o, p’-DDE, p, p’-DDE, ¹³C₁₂ labeled p, p’-DDE, D₈ labeled p, p’-DDT, phenanthrene D-10, and chrysene D-12. The hypochlorite solution used for synchronization was prepared using household bleach (Clorox, 8% sodium hypochlorite), water, and 1N sodium hydroxide.

The 57 pesticides and 3 degradation products that were used in this study were divided into six categories according to chemical group as shown in Table 1, including amides/anilines, azoles, carbamates, heterocyclic, organophosphates and triazines. The names, CAS numbers and companies from which the 57 pesticides and 3 degradation products were purchased are listed in Table S2. The recovery indicators phenanthrene-d10 and atrazine-d5 were purchased from Accustandard, New Haven, CT, USA. All of the solvents used in this study, including methanol, n-hexane (HEX) and dichloromethane (DCM), were of high-performance liquid chromatography (HPLC) grade (Thermo Fisher Scientific, Waltham, MA, USA). Glass fiber filters with a 0.7 μm aperture were purchased from Millipore, Billerica, MA, USA; anhydrous sodium sulfate was purchased from Sinopharm Chemical Reagent Co., Ltd., Shanghai, China; ultrapure water was prepared using a RephiLe-J24617 system (PURIST PRO, Lefeng Biotechnology Co., Ltd., Shanghai, China); the C18 (6 cc 500 mg) solid phase extraction (SPE) columns and HLB (6 cc 500 mg) SPE columns were purchased from Waters, Milford, MA, USA; celite was purchased from J&K Scientific, Beijing, China; and Florisil (6 mL, 1 g) SPE columns were purchased from Supelco, Merck, Darmstadt, Germany.