Chlorpyrifos

All chemicals and solvents were of analytical quality grade. HPLC grade acetonitrile (MeCN) and methanol (MeOH) were purchased from LabScan (Dublin, Ireland). Insecticide standards, chlorpyrifos (98.3%), acrinathrin (99.7%), deltamethrin (99.9%) and ʎ-cyhalothrin (≥95.0%) were supplied by Sigma-Aldrich (St. Louis, MO, USA), Table 1. Buffered salts for QuEChERS extraction, including anhydrous magnesium sulphate (MgSO₄), sodium hydroxide (NaOH), sodium chloride (NaCl), trisodium citrate dihydrate (C₆H₅Na₃O₇·2H₂O) and disodium hydrogencitrate sesquihydrate (C₆H₈Na₂O₈), were also obtained from Sigma-Aldrich. dSPE clean-up tubes with primary secondary amine (PSA) and MgSO₄ were obtained from Waters (Milford, MA, USA). Phosphoric acid (PhA, ≥85%) was from BDH (Poole, UK), while formic acid (FA, ≥99%) was obtained from Merck (Darmstadt, Germany). Ultrapure water (H₂O) from a Milli-Q ultrapure water purification system (Millipore, Bedford, USA) was used for preparing the UHPLC mobile phase and other aqueous solutions. Filters of 13 mm with 0.22-µm PTFE membranes were used for filtration of the final extracts before UHPLC-PDA analysis.

Analytical grade Chlorpyrifos (purity 99.9%) was purchased from Sigma-Aldrich Co. (St. Louis, MO, United States). Other chemicals used in this study were also analytical grade quality and purchased from Merck, India. Media used were purchased from Hi-Media Laboratories, Mumbai, India. Mineral salt medium (stocktickerMSM) used in this study contained (g L^–1): (NH₄)₂SO₄ 2.0, MgSO₄.7H₂O 0.2, CaCl₂.2H₂O 0.01, FeSO₄.7H₂O 0.001, Na₂HPO₄.12H₂O 1.5, and KH₂PO₄ 2.0. The stock solution of Chlorpyrifos (2150 g L^–1) and 3, 5, 6-trichloro-2-pyridinol (100 mg L^–1) was prepared in a mixture of acetone + n-hexane (50:50) and passed through 0.22-μm syringe filters.

Phosphate buffer saline with potassium chloride (10 mm) tablets at pH 7.4, glutaraldehyde (25%), flavin adenine dinucleotide, sodium chloride, perchloric acid (70%), chloroplatinic acid (8%), glyphosate, atrazine, aminomethylphosphonic acid, thiamethoxam, imidacloprid, clothianidin, paraoxon‐methyl, parathion‐methyl, malathion and chlorpyrifos were purchased from Sigma Aldrich. 2,4‐dichlorophenoxyacetic acid was purchased from Tokyo Chemical Industry, and dicamba was provided by the Iowa State University chem service. The glycine oxidase gene originates from Bacillus subtilis and gives rise to a 47 kDa protein.^[84, ^92] Glycine oxidase (40 µm) was prepared by the U.S. Naval Research Laboratory in a manner similar to that described in references.^[93, ^94]glutaraldehyde dilutions were prepared in PBS pH 7.4. flavin adenine dinucleotide dilutions were prepared in PBS in a pH range from 5.4–9.4. All pesticides were prepared in 10× PBS pH 7.4. Kapton polyimide substrate (0.125 µm thick) was purchased from McMaster‐Carr. River water samples were gathered from the South Skunk River in Iowa. Crop residues were tested on crops purchased from a local grocery market.

Polycaprolactone polymer (PCL, average M_n ≈ 80 000, ρ = 1.15 g cm^–3, T_m = 61 °C) was
used for the fabrication of the electrospun fibers. Chlorpyrifos (PESTANAL,
analytical standard), and Copper nanopowder (Cu, average particle
size 25 nm) were purchased from Sigma-Aldrich, the absence of oxidized
Cu due to the storage was confirmed by Raman spectroscopy (see Supporting
Information, Figure S3). Chloroform, methanol,
and ethanol were purchased from Scharlab. Deionized water was obtained
from a RiOs-DI 3 Water Purification device.

HPLC-grade acetonitrile was obtained from Merck (Darmstadt, Germany). Analytical grade standard chlorpyrifos (>99%), formic acid, and ammonium acetate were obtained from Sigma-Aldrich (Sydney, Australia). All test kits for analyzing MDA, soluble protein, and POD and SOD activities were obtained from Nanjing Jiancheng Bioengineering Institute Co., Ltd. (Nanjing, China). The stock standard solutions of chlorpyrifos were prepared in acetonitrile and stored in amber glass vials at 4 °C.

Mouse monoclonal anti-PON2 antibody (sc373981), mouse monoclonal anti-ACTIN antibody (sc32251) and goat anti-mouse horseradish peroxidase-conjugated secondary antibody (sc2005) were purchased from Santa-Cruz, USA. DMEM F12 and fetal calf serum were procured from Invitrogen (Carlsbad, CA). Dimethyl sulfoxide (DMSO), 2′,7′-dichlorodihydrofluorescein diacetate (DCFDA), ter-butyl hydroperoxide (tBH) and paraoxon (O, O-diethyl-o-p-nitro-phenylphosphate), chlorpyrifos and mithramycin was from Sigma-Aldrich (St. Louis, MO). Enhanced chemiluminescence western blotting detection reagents were from Amersham Biosciences UK, Ltd. (Little Chalfont, Buckinghamshire, UK). Redox assay kit was procured from Oxford Biomedical Research, MI, USA.