Deuterated zen zen d6

Organic solvents of analytical grade, formic acid, nitric acid, ammonium formate, hydrochloric acid (reagent grade), iron (III) chloride hexahydrate, ethylene glycol, trisodium citrate, sodium acetate, poly(ethyleneglycol)-10k, and GCB (Supelclean ENVI-Carb, surface area: 100 m²/g, particle size: 120/400 mesh) were obtained from Sigma-Aldrich (St. Louis, MO, USA). LC-MS grade methanol and ultrapure water (resistivity 18.2 MΩ cm) were obtained from Sigma Aldrich and used for LC mobile phase.
Pure (purity ≥98%, unless differently specified) standards of the analytes AFB1, AFB2, AFG1, AFG2, OTA, and ZEN (purity ≥99%) were purchased from Sigma-Aldrich. The standards of aflatoxin M1 (AFM1) and deuterated OTA (OTA-d5) acquired from Sigma-Aldrich, and deuterated ZEN (ZEN-d6) acquired from Wellington Laboratories (Toronto, ON, Canada) were used as internal standards (ISs).
Individual stock standard solutions of the analytes were prepared at 200 ng µL⁻¹ in methanol. A composite working standard solution of the six analytes was prepared in methanol at 10 pg µL⁻¹ for AFB1, AFB2, AFG1, and AFG2, 30 pg µL⁻¹ for OTA, and 750 pg µL⁻¹ for ZEN. This mixture was renewed every two weeks. All the solutions were stored in the dark at −20 °C and brought to room temperature before use.

Organic solvents of analytical grade, formic acid, ammonium formate, as well as LC-MS grade methanol and ultrapure water (resistivity 18.2 MΩ cm) were obtained from Sigma-Aldrich now Merck (Darmstadt, Germany).
The authentic standards (purity ≥ 99%) of ZEN (CAS n. 17924-92-4), ZAN (CAS n. 5975-78-0), α-ZEL (CAS n. 36455-72-8), β-ZEL (CAS n. 71030− 11-0), DAD (CAS n. 486-66-8), GEN (, CAS n. 446-72-0), QUE (CAS n. 6151-25-3), HT-2 (CAS n. 26934-87-2), and DON (CAS n. 51481− 10-8) were purchased from Sigma-Aldrich (Darmstadt, Germany). Deuterated ZEN (ZEN-d6) was acquired from Wellington Laboratories (Toronto, ON, Canada) and used as IS. For each analyte, an individual stock standard solution at 200 μg mL⁻¹ concentration was prepared by dissolving the suitable amount of standard in methanol. All the solutions were stored in the dark at −20 °C and brought to room temperature before use.