Ammonium acetate

8-OHdG and HPLC-grade methanol were obtained from Sigma-Aldrich (St. Louis, MO, USA), HNE-MA was obtained from Zzstandard (Shanghai Zzbio Co. Ltd., Shanghai, China), the internal standards 15 N5-8-OHdG (25 μg/ml in water, 98% purity) and HME-NA-d3 (>98% purity) were obtained from Cambridge Isotope Laboratories (Andover, MA, USA), and 8-isoPGF_2α and its internal standard 8-isoPGF_2α-d4 were obtained from Cayman Chemicals (Ann Arbor, MI, USA). Purified water was obtained using a Milli-Q system (Millipore, Bedford, MA, USA). Ammonium acetate was purchased from Sinopharm Chemicals (Shanghai, China).

The LC-MS grade methanol, ethanol, acetonitrile, formic acid, 0.1% (w/v) poly(L-lysine) hydrobromide solution, and gelatin were obtained from Sigma-Aldrich (Shanghai, China). Analytical grade ammonium acetate, chloral hydrate, phloroglucinol, iodine, sulfuric acid, and ethanol were obtained from Sinopharm Chemical Reagent Co., Ltd (Beijing, China). The optimum cutting temperature (OCT) compound was obtained from Leica (Nussloch, Germany). Water was purified by employing a Milli-Q filtration system (Millipore, Bedford, USA). Information for the reference standards could be found in Table 1. Sixty-four batches of Isatidis Radix were purchased from herb markets in the provinces of Hebei, Gansu, Sichuan, and Heilongjiang, China. The origin of each sample was authenticated as the dried root of Isatis tinctoria L. (Brassicaceae) by Associate Professor Shuai Kang in accordance with the Chinese Pharmacopeia, edition 2020. For future reference, the voucher specimens (S1–S64) were deposited in NIFDC, Beijing, China.

All the organic solvents, acids, alkalis and salts were HPLC or analytical grade. Acetonitrile and methanol were purchased from Merck (Darmstadt, Germany). Ammonium acetate, formic acid, aqueous ammonia, FeCl₃·6H₂O (≥99.5%) and FeCl₂·4H₂O (≥99%) were provided by Sinopharm Chemical Reagent Co. (Shanghai, China).1,2-dichlorobenzene, 1-Butanol and 1,4-Dioxane were supplied by Macklin Co. (Shanghai, China). DHTA and TAPT were obtained from Yuanye Bio-Technology Co. (Shanghai, China). Nylon filters (0.22 μm) were obtained from Navigator Lab Instrument Co. Ltd. (New York, NY, USA). Deionized water was prepared by a Milli-Q water purification system (Millipore, Bedford, MA, USA).
High purity (≥98%) standards of TeA, AOH, AME, TEN, ALT, ALS, AFB₁, OTA and ZEN were obtained from Sigma-Aldrich (St. Louis, MO, USA). Standard stock solutions of the nine mycotoxins (10 μg mL⁻¹) were prepared in Acetonitrile and stored at −20 °C in the dark. Their chemical structures and physicochemical parameters are shown in Table S1.
A total of 100 random fruit samples were provided by local markets and supermarkets in Shanghai. The samples were ground into powder or pulp and stored at −20 °C.

Acetonitrile and methanol were purchased from Merck KGaA (Darmstadt, Germany). Chloramphenicol used as the internal standard (IS) was obtained from Aladdin reagent Co., Ltd. (Shanghai, China). Ammonium acetate and CCl₄ were purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China). Deionized water was prepared by a Milli-Q system (Millipore, Bedford, MA, USA). Jujubae Fructus was gathered at Liuling, Shanxi Province, China. The standards (>98% purity) including ceanothic acid, epiceanothic acid, pomonic acid, alphitolic acid, maslinic acid, betulinic acid and betulonic acid were isolated from Z. jujuba fruits in our laboratory, and their structures were identified by NMR, HPLC and MS. Other reagents used were of analytical grade.
TAE of Jujubae Fructus prepared in our previous experiment [24 (link)] was used in this experiment, which contains ceanothic acid, epiceanothic acid, pomonic acid, alphitolic acid, maslinic acid, betulinic acid, and betulonic acid with the contents of 0.78, 0.44, 24.08, 4.97, 17.31, 16.79 and 14.29 mg/g, respectively.