Octadecyl carbon chain bonded silica c18

Methanol (MeOH),
acetonitrile (ACN), and water for the LC mobile phase (LC-MS grade)
were purchased from Merck (Darmstadt, Germany). Ammonium formate (analytical
grade) was acquired from Fluka (Milan, Italy), and formic acid (MS
grade) was provided by Carlo Erba Reagents (Cornaredo, Italy). Sodium
chloride (NaCl) and octadecyl carbon chain-bonded silica (C18) (analytical
grade) were purchased from Sigma-Aldrich (Milan, Italy). Conical centrifuge
polypropylene tubes of 15 mL were obtained from BD Falcon (Milan,
Italy). Syringe filters with polytetrafluoroethylene membrane (PTFE,
15 mm, diameter 0.2 μm) were acquired from Phenomenex (Castel
Maggiore, Italy).
Analytical standards of CIT and DH-CIT (HPLC
purity >98%) were acquired from Sigma-Aldrich (Milan, Italy) and
Analyticon
Discovery GmbH (Potsdam, Germany), respectively. Stock solutions were
prepared diluting 1 mg of each mycotoxin in 1 mL of MeOH. Working
solutions were built from the stock, diluting in MeOH/H₂O (70:30 v/v) 0.1% formic acid until reaching the desired concentrations
for spiking experiments. The solutions were stored in tightly closed
containers at −20 °C in a well-ventilated place as specified
by the manufacturer.

Methanol (MeOH), acetonitrile water, and formic acid (FA) for LC mobile phase (HPLC grade) were purchased from Merck (Darmstadt, Germany). Sodium chloride (NaCl), ammonium formate (NH₄HCO₂), magnesium sulfate (MgSO₄), and octadecyl carbon chain-bonded silica (C18) were acquired from Sigma Aldrich (Milan, Italy). Eighteen mycotoxin standards (purity >98%) including aflatoxins (AFB1, AFB2, AFG1, and AFG2), zearalenone (ZEN), α-zearalanol (α-ZAL), α-zearalenol (α-ZEL), β-zearalanol (β-ZAL), neosolaniol (NEO), T-2 toxin, HT-2 toxin, enniatins (A, A1, B, and B1), alternariol monomethyl ether (AME), and alternariol (AOH) were obtained from Sigma-Aldrich (Milan, Italy).
Stock solutions of each mycotoxin were built by dissolving 1 mg of solid reference standard in 1 mL of methanol. An intermediate mixed solution containing all the mycotoxins at a concentration of 30 μg/mL was obtained after mixing individual stock solutions and diluting in MeOH:H₂O (70:30 v/v) 0.1% formic acid. Working standard solutions at 1.6, 0.4, 0.08 μg/mL were used for spiking experiments (fortification levels at 20, 5, and 1 µg/kg). All solutions were stored in safe conditions at −20 °C in screw-capped glass vials.

Water for the LC mobile phase (LC-MS grade), acetonitrile (AcN) and methanol (MeOH) were acquired from Merck (Darmstadt, Germany). Formic acid (MS grade) was supplied by Carlo Erba reagents (Cornaredo, Italy). Ammonium formate (analytical grade) was purchased from Fluka (Milan, Italy). Octadecyl carbon chain-bonded silica (C18) (analytical grade) and sodium chloride (NaCl) were obtained from Sigma Aldrich (Milan, Italy). Conical centrifuge polypropylene tubes of 15 mL were provided by BD Falcon (Milan, Italy). Syringe filters with polytetrafluoroethylene membrane (PTFE, 15 mm, diameter 0.2 µm) were acquired from Phenomenex (Castel Maggiore, Italy).
Analytical standards of T-2 and HT-2 (HPLC purity > 98%) were supplied by from Sigma-Aldrich (Milan, Italy). Stock solutions were built by diluting 1 mg of each standard mycotoxin in 1 mL of MeOH. Then, working solutions were prepared by properly diluting with MeOH/H₂O (70:30 v/v) 0.1% formic acid to reach the concentrations needed for spiking experiments (5, 1 and 0.5 ng/g). The solutions were kept in securely closed vials at −20 °C.