Hplc grade acetonitrile acn

The analytical standard fluxapyroxad (99.5% purity) was purchased from Supelco (Supelco Inc., Bellefonte, PA., USA)). HPLC-grade acetonitrile (ACN) was purchased from Honeywell (Charlotte, NC, USA), and petroleum ether (fraction boiling at 40–60 °C) of GC purity was supplied by Chempur (Piekary Śląskie, Poland). Sorbents: analytical grade MgSO₄ and NaCitrate (Chempur, Piekary Śląskie, Poland), NaCl (Honeywell, Charlotte, NC, USA), disodium citrate sesquihydrate (Sigma Aldrich, Saint Louis, MO, USA), and primary-secondary amine (PSA) (Supelco Inc., Bellefonte, PA, USA) were used for QuEChERS extraction and purification.
Standard stock solutions of fluxapyroxad (1000 mg/L) were prepared in pure acetone, and were stored in the dark below − 20 °C. Standard working solutions of fluxapyroxad, at concentrations of 0.005, 0.01, 0.05, 0.1, 0.5, and 1 mg/L, were prepared from the stock solution by serial dilution. Correspondingly, matrix-matched standard solutions were obtained, at concentrations of 0.005, 0.01, 0.05, 0.1, 0.5, and 1 mg/L, by adding a blank sample matrix of apples to each serially diluted standard solution. All solutions were stored in a refrigerator in the dark at 4 °C. Apples for the preparation of a blank matrix were sampled from an organic orchard.

SBN (purity ≥95.0%), potassium phosphate monobasic/dibasic, and dimethyl sulfoxide (DMSO) were obtained from Sigma-Aldrich Co. (St. Louis, MO, USA). Diclofenac (purity ≥98.0%) was obtained from Tokyo Chemical Industry Co. (Tokyo, Japan). HPLC-grade acetonitrile (ACN) was obtained from Honeywell, Inc. (Muskegon, MA, USA). The silymarin products from four different manufacturers, indicated as ′Commercial product #1–4′, were evaluated. The names of the manufacturers were not disclosed for privacy reasons.

Reference standards of Zen (≥ 99%), Zer (≥ 98%, HPLC grade), zearalanone (Zan; ≥ 98%), β-zearalanol (bZal; ≥ 96%, HPLC grade), α-zearalenol (aZol; ≥ 98%), and β-zearalenol (bZol; ≥ 97%) were obtained from Sigma-Aldrich. The internal standards Rac-Zearalenone-d₆ (Zen-d₆; ≥ 96.9%) and α-zearalenol-d₇ (aZol-d₇; ≥ 98%) were obtained from Toronto Research Chemicals. Sodium acetate buffer solution (pH = 4.65, 0.2 M) was purchased from Honeywell Fluka. The enzyme β-glucuronidase from Helix pomatia (type HP-2, > 100,000 units/mL, sulfatase activity < 7500 units/mL) was obtained from Sigma-Aldrich. HPLC-grade methyl tert-butyl ether (MTBE) and methanol (MeOH) were purchased from VWR. HPLC-grade acetonitrile (ACN) was purchased from Honeywell. Water was obtained from a Milli-Q water purification system (Millipore).

Crude LDX and its impurities were synthesized in our laboratory. l-Lysine hydrochloride (2), (S)-1-phenylethanamine (3) and methanesulfonic acid were purchased from Energy Chemical Corporation (Shanghai, China). The purity of all substances was >98%. HPLC-grade methanesulfonic acid were purchased from Fisher Scientific (Waltham, MA, USA). HPLC-grade acetonitrile (ACN) was purchased from Honeywell (Newark, NJ, USA). Deionized water for preparing the aqueous phase was obtained using a water purification system and all other chemicals were of analytical grade.

All the chemicals and reagents used were of analytical grade. Bovine serum albumin (BSA), formic acid (FA), dithiothreitol (DTT), and iodoacetamide (IAM) were purchased from Sigma-Aldrich (Burlington, MA, USA). Ammonium bicarbonate (AMBIC) was purchased from J.T. Baker (Phillipsburg, NJ, USA). Protein Assay dye was purchased from Bio-Rad (Hercules, CA, USA). The ExcelBand™ 3-color broad-range protein marker (5–245 kDa) was purchased from Smobio (Hsinchu, Taiwan). C₁₈ RP-HPLC column (250 × 4.6 mm, 5 μm particle) was obtained from Thermo Scientific™ BioBasic™ (Waltham, MA, USA). HPLC grade acetonitrile (ACN) was purchased from Honeywell (Charlotte, NC, USA). Trifluoroacetic acid (TFA) was purchased from Acros Organics (Geel, Belgium). Sequence-grade modified trypsin was purchased from Promega (Madison, WI, USA).