Ammonium formate

Methanol (MeOH) and acetonitrile (MeCN) of LC-MS grade, and ammonium formate were supplied by VWR International Eurolab S.L. (Barcelona, Spain). Formic acid eluent additive for LC–MS was obtained from Sigma Aldrich (St. Louis, MO, USA). Magnesium sulphate (MgSO₄), sodium chloride (NaCl) and sodium citrate were purchased from Panreac Química (Barcelona, Spain), while disodium hydrogen citrate sesquihydrate was supplied by Merck (Darmstadt, Germany). Ultrapure water was obtained from a Milli-Q Plus system (Millipore Bedford, MA, USA).
Mycotoxin standard solutions (10 mg/L in MeCN) of OTA, STE, F-X, DON, CIT, ZEN, FB1, FB2, T-2 and HT-2 were purchased from Techno Spec (Barcelona, Spain). Individual standards (powder) of ENNA, ENNA1, ENNB, ENNB1 and BEA were obtained from Sigma Aldrich and stock solutions were prepared at 1000 mg/L in MeCN. Multi-mycotoxins intermediate working solutions in MeCN (1 mg/L of OTA and STE; 2 mg/L of CIT; 10 mg/L of FB1, FB2, T-2, HT-2 and ZEN; 100 mg/L of DON, ENNA, ENNA1, ENNB, ENNB1 and BEA and 1000 mg/L of F-X) were prepared by combining suitable aliquots of each individual standard stock solution. These solutions were stored at −20 °C.
Nylon syringe filters (13 mm, 0.22 μm, from VWR) were used for filtration of extracts prior to the injection into the chromatographic system.

UPLC grade methanol (MeOH), acetonitrile (ACN), ethyl acetate, and water were obtained from Actu-all chemicals (Oss, Netherlands). Formic acid (FA), acetic acid (HAc), sodium acetate, ammonium formate, and ammonium carbonate were obtained from VWR International (Darmstadt, Germany). Magnesium sulfate, dimethyl sulfoxide (DMSO), β-glucoronidase/arylsulfatase from Helix Pomatia, dipotassium phosphate, and potassium dihydrogen phosphate were obtained from Sigma-Aldrich (St. Louis, USA). Bondesil PSA was obtained from Agilent Technologies (Santa Clara, USA). Bakerbond C18 was purchased from Avantor Performance Materials (Phillipsburg, USA).
Analytical reference standards and isotope labelled internal standards were purchased from LGC Standards (Teddington, UK), Toronto Research Chemicals (Toronto, Canada), Sigma-Aldrich, HPC Standards (Cunnersdorf, Germany), Bayer CropScience (Monheim am Rhein, Germany), and MerchaChem (Nijmegen, Netherlands). Reference standards of chlorpyrifos-methyl-desmethyl and chlorpyrifos-desethyl were kindly donated by CVUA (Stuttgart, Germany).
Oasis HLB 60 µm/60 mg 96-well plates were purchased from Waters (Milford, USA), Strata-X polymeric reversed phase cartridges (200 mg/6 mL) were purchased from Phenomenex (Utrecht, the Netherlands), and Amicon Ultra 30 kDa centrifugal filter units were purchased from Sigma-Aldrich.

Sodium ampicillin 50 g vials were obtained from Normon (Madrid, Spain). Sodium chloride 0.9% was purchased from Baxter (Deerfield, IL, USA) and water for injection was obtained from Grifols (Barcelona, Spain). Water, acetonitrile, ammonium formate, formic acid, and methanol UHPLC-MS-grade were purchased from VWR Chemicals (Radnor, PA, USA). Elastomeric infusion pumps DOSI-FUSER 250 mL (L25915-250D1) and cooling devices were supplied by Leventon (Barcelona, Spain). The DOSI-FUSER devices are composed of a core balloon of polyisoprene (latex-free) and a di(2-ethylhexyl) phthalate (DEHP)-free vinyl polychloride (PVC) infusion line. The cooling devices consisted of a portable cooling device with a zipper closing designed to contain one EIP and one ice pack, which must be kept at −20 °C at least for 24 h before use.