Lc grade acetonitrile

Ochratoxin A stock solution (10 ppm) and ¹³C₂₀-ochratoxin A (10 ppm) were purchased from Romer Labs, Inc. (Newark, DE, USA). LC grade acetonitrile, water, and MS grade formic acid and ammonium formate were purchased from Thermo Fisher Scientific, (Waltham, MA, USA). A working solution of ¹³C₂₀-ochratoxin A (¹³C-IS) was prepared at 500 ppb in acetonitrile. Calibration solutions of ochratoxin A ranging from 0.01 to 1000 ppb were prepared by a series of dilutions of the stock solution using acetonitrile. An incurred corn reference material (SRM 1565) was purchased from NIST (Gaithersburg, MD, USA). A second incurred corn sample (MT-C-9999G) was purchased from Trilogy Analytical Laboratory (Washington, MO, USA). Two incurred wheat flour samples (OW-821 and OW-825) and one incurred oat sample (C-3023) were purchased from Romer Labs (Newark, DE, USA).

[2,2′-azino-bis-(3-ethylbenzo-thiazoline-6-sulfonic acid)] (ABTS free radical), D-galactose and ascorbic acid (VC) were received from Solarbio Science and Technology Co., Ltd. (Beijing, China). LC grade acetonitrile was supplied by Thermo Fisher Scientific Inc. (USA). Caffeic and rosmarinic acids standards were purchased from SIGMA-ALDRICH Co., Ltd. (USA). Ferulic acid was purchased from Yuanye Biotechnology Co., Ltd. (Shanghai, China). 2,2′-diphenyl-1-picrylhydrazyl (DPPH free radical) was purchased from TCI Development Co., Ltd. (Shanghai, China). The biochemical assay kits used for determination of superoxide dismutase (SOD), malondialdehyde (MDA), catalase (CAT) and glutathione peroxidase (GSH-px) were received from Elabscience Biotechnology Co., Ltd. (Wuhan, China). All the chemicals used in the study were of analytical grade.

Deionized water was obtained using a Milli-Q (Merck Millipore, Massachusetts, USA) laboratory water purification system. LC grade MeOH, LC grade acetonitrile (ACN), ammonium acetate and formic acid (HCOOH) were obtained from Thermo Fisher Scientific (Loughborough, UK). Tween 20 was obtained from Sigma-Aldrich Ltd (Gillingham, UK). PBS tablets were obtained from R-Biopharm Rhone Ltd. One tablet was dissolved in 100 mL water to give an 8.0 g/L solution of sodium chloride, 0.2 g/L potassium chloride, 1.15 g/L di-sodium hydrogen phosphate, and 0.2 g/L potassium dihydrogen phosphate with a of pH 7.3 ± 0.2 at 25°C.

LC grade acetonitrile, methanol, and water were purchased from Thermo Fisher Scientific (Waltham, MA, USA). Mycotoxin stock solutions I, II, and III were obtained from Romer Labs (Union, MO, USA). Solution I contained 10 μg/mL each of aflatoxin B₁ (AFB1), aflatoxin B₂ (AFB2), aflatoxin G₁ (AFG1), aflatoxin G₂ (AFG2), and ochratoxin A (OTA) in methanol; Solution II contained 100 μg/mL each of fumonisin B₁ (FB1), fumonisin B₂ (FB2), and fumonisin B₃ (FB3) in acetonitrile–water (1 + 1, v/v); Solution III contained 100 μg/mL each of deoxynivalenol (DON), HT-2 toxin (HT-2), T-2 toxin (T-2), and zearalenone (ZON) in acetonitrile. The following carbon-13 (¹³C)-IS stock solutions were purchased from Romer Labs: ¹³C₁₇-AFB1 + B2 + G1 + G2 (0.5 μg/mL), ¹³C₂₀-OTA (10 μg/mL), ¹³C₃₄-FB1 (25 μg/mL), ¹³C₃₄-FB2 (10 μg/mL), ¹³C₃₄-FB3 (10 μg/mL), ¹³C₁₅-DON (25 μg/mL), ¹³C₂₂-HT-2 (25 μg/mL), ¹³C₂₄-T-2 (25 μg/mL), and ¹³C₁₈-ZON (25 μg/mL).Spiking solutions of ¹³C-IS and calibration standards were prepared according to a previously described protocol [22 (link)].