Milli q sp reagent water system

Reagents and chemicals employed are described in detail in a previous work [31 (link)].
Methanol (MeOH) and acetonitrile (ACN), (HPLC grade) and Chloroform (CHCl3) (99% grade) were purchased from Merck (Darmstadt, Germany). Ethyl acetate (EtOAc) (HPLC grade 99.5+%) was supplied by Alfa Aesar (Karlsruhe, Germany). Deionized water (resistivity > 18 MΩ cm⁻¹) was obtained from a Milli-Q SP^® Reagent Water System (Millipore Corporation, Bed-ford, MA, USA). Ammonium formate salt (99%) was obtained from Panreac Quimica S.A.U. (Barcelona, Spain) and sodium chloride (NaCl) was supplied by VWR Chemicals (Leuven, Belgium). Formic acid (reagent grade ≥ 95%) was supplied by Sigma-Aldrich (St. Louis, MO, USA). Enniatin standards (ENNA, ENNA1, ENNB and ENNB1) were purchased from Sigma (St. Louis, MO, USA).

The analytical standards of the 6 flavonoid phenolic compounds namely, quercetin (≥95.0%, HPLC), rutin (≥95.0%, HPLC), isorhamnetin (≥95.0%, HPLC), quercetin-3-glucouronide (≥95.0%, HPLC), hyperoside (≥97.0%, HPLC), and quercitrin (≥95.0%, HPLC) were supplied by Sigma-Aldrich (Milan, Italy). Every day, suitable dilutions of the stock solutions with HPLC-grade methanol were used to create standard working solutions at various concentrations. Formic acid (99%) came from Merck (Darmstadt, Germany). Carlo Erba Reagents (Milan, Italy) provided analytical-grade hydrochloric acid (37%). Methanol suitable for HPLC was provided by Sigma-Aldrich (Milano, Italy). Deionized water was again purified (>18 MΩ cm resistivity) using a Milli-Q SP Reagent Water System (Millipore, Bedford, MA, USA). All solutions were filtered through a 0.2 μm polyamide filter obtained from Sartorius Stedim (Goettingen, Germany). All samples were filtered through Phenex™ RC 4 mm 0.2 μm syringeless filter supplied by Phenomenex (Castel Maggiore, BO, Italy), before HPLC analysis.

PhytoLab provided analytical standards for kaempferol-3-glucoside and quercetin-3-glucoside (Vestenbergsgreuth, Germany). Sigma-Aldrich provided the reference materials for the remaining 27 of the 29 phenolics (Milan, Italy). Stock solutions of each analyte (1000 mg L⁻¹) were made by dissolving pure reference materials in methanol (HPLC-grade) and then keeping them at 5 °C in glass stoppered bottles until analysis. Working solutions of standards at different concentrations were made fresh by diluting stock solutions with methanol (HPLC-grade). Merck provided formic acid at a concentration of 99% (Darmstadt, Germany). Carlo Erba Reagents provided hydrochloric acid (analytical grade) at a concentration of 37% (Milan, Italy). Methanol of HPLC quality was acquired from Sigma-Aldrich, located in Milan, Italy. A Milli-Q SP Reagent Water System filtered deionized water to give ultrapure water with a resistivity of >18 M cm (Millipore, Bedford, MA, USA). Sartorius Stedim provided 0.2 μm polyamide filters which were used to filter all liquids (Goettingen, Germany). Phenex™ RC 4 mm 0.2 μm syringeless filters purchased from the company of Phenomenex, located in Castel Maggiore, BO, Italy, were used to filter all samples before injection into the HPLC instrument.

The analytical standards of hydroxytyrosol, tyrosol, vanillic acid, oleuropein, luteolin, and apigenin were purchased from Extrasynthese (Genay, France). p-Coumaric acid, ferulic acid, pinoresinol, syringic acid, α-tocopherol, 2,2’-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS), and Trolox were purchased from Sigma-Aldrich (Milan, Italy). High performance liquid chromatography (HPLC) -grade methanol, hexane, and isopropanol (IPA) were purchased from Sigma-Aldrich (Milan, Italy). Water (resistivity above 18 MΩ cm) was obtained from a Milli-Q SP Reagent Water System (Millipore, Bedford, MA, USA). Solvents and solutions were filtered through a 0.45-µm polytetrafluoroethylene (PTFE) filter from Supelco (Bellefonte, PA, USA).

HPLC grade solvents (hexane, methanol (MeOH) and acetonitrile (AcN)) were purchased from Merck (Darmstadt, Germany). Deionized water (<18 MΩ cm resistivity) was obtained in the laboratory using a Milli-Q SP Reagent Water System (Millipore, Bedford, MA, USA).
Standards of mycotoxins including (aflatoxins (B1, B2, G1 and G2); enniatins (A, A1, B and B1); fumonisins (B1 and B2); nivalenol (NIV); deoxynivalenol (DON); 15-acetyldeoxynivalenol (15-ADON); 3-acetyldeoxynivalenol (3-ADON); zearalenone (ZEA); beauvericin (BEA); fusarenon X (FUS-X)) were purchased from Sigma Aldrich (Madrid, Spain). The T-2 and HT-2 toxins were provided from BiopureReferenzsubstanzenGmBH (Tulln, Austria). Finally, fumonisin B3 was provided by the Research Program “PROMEC” (Tygerberg) in South Africa. All stock solutions of mycotoxins standards were stored in glass-stoppered bottles in darkness at −20 °C until the final analysis. For the derivatization, the reagent composed of BSA (N,O-bis (trimethylsilyl) acetamide)/TMCS (trimethylchlorosilane)/TMSI (N-trimethylsilyimidazole) (3:2:3) was obtained from Supelco (Bellefonte, PA, USA).

AAPH (2,2′-azobis (2-amidinopropane)) (Acros Organics), sodium phosphate dibasic, sodium chloride, potassium dihydrogen phosphate, potassium sulphate, TRIS (ultrapure), glycine (proteomics grade), ortho-boric acid, and methanol (HPLC grade) were obtained from VWR International Eurolab S.L. (Barcelona, Spain). Trizma^® base, ABTS (2,2′-azinobis (3-ethylbenzothiazoline 6-sulfonic acid)), DTT (DL-Dithiothreitol), Trolox^® (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), fluorescein sodium salt, formic acid (reagent grade ≥ 95%), and diatomaceous earth (Hyflo^® Super Cel^®) were provided by Sigma-Aldrich (Steinheim, Germany). Sodium hydroxide, glacial acetic acid, and sulfuric acid were supplied by Fisher Scientific (Madrid, Spain). SDS (sodium dodecyl sulfate) and nitric acid (65% p/p) were purchased from Panreac (Barcelona, Spain). Bromophenol blue indicator (ACS reagent), acetonitrile (HPLC grade), trifluoroacetic acid, acetone, and glycerol were provided by Merck (Darmstadt, Germany). Absolute ethanol was obtained from J.T. Baker (Deventer, The Netherlands), Octadecyl C18 sorbent was obtained from Phenomenex (Madrid, Spain), and anhydrous magnesium sulfate (99.5% min powder) was obtained from Alfa Aesar (Karlsruhe, Germany). Deionized water with a resistivity of >18 MΩ/cm was obtained through a Milli-Q SP^® Reagent Water System (Millipore Corporation Bedford, MA, USA).