Boron trifluoride bf3

The subjects of the study were flour samples from the following oilseed cakes: pumpkin, flax, evening primrose, milk thistle, corn germ, almond and peanut, obtained from the Ol’Vita company (Myslakow, Poland). Flours were obtained by milling the seed cakes obtained during the cold-pressing production of oil. The ready products were packed into polypropylene bags and closed with a clip, leaving a small space filled with air above the sample. The weight of one package was 250 g. Samples were stored in the laboratory in their original, commercial packages at 22 ± 1 °C in the dark.
All reagents used were of analytical grade. Methanol, Folin–Ciocalteu reagent, 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS), boron trifluoride (BF₃) and diethyl ether were purchased from Sigma (St. Louis, MO, USA). Ninhydrin, hydrindantin, methylcellosolve and sodium acetate buffer were purchased from INGOS (Prague, Czech Republic).

Analytical grade hexane, dichloromethane and methanol were obtained from Fisher Chemicals (Hampton, NH, USA) and used as extraction solvents. LC-MS grade solvents, water and acetonitrile were purchased from J.T. Baker (Phillipsburg, NJ, USA), while formic acid (LC-MS grade) was obtained from Fisher Chemicals. For the LC–MS/MS determinations (Hampton, NH, USA).
All standards used for the phytoestrogens’ quantification analysis were provided by ExtraSynthese (Genay, France), except equol and puerarin, which were obtained from TCI (Tocyo Chemical Industry, Zwijindrecht, Belgium), and calycosin, calycosin-7-O-β-D-glucoside, matairesinol, lariciresinol and secoisolariciresinol, which were purchased from Biosynth Carbosynth (Compton, United Kingdom). The purity of al standards was >95%, except 3′,4′,7-trihydroxyflavone (purity > 90%). The 2-(4-chlorophenyl) malonaldehyde molecules used as internal standard were obtained from Sigma-Aldrich (Burlington, MA, USA)). The standard used for the fatty acids’ quantification analysis was the Supelco 37 Component FAME Mix from Sigma-Aldrich.
Potassium hydroxide (KOH) and boron trifluoride (BF₃) (14% in methanol) were obtained from Sigma-Aldrich, and hydrochloric acid (HCl) was from Fluka (Buchs, Switzerland).

Five types of mushrooms, oyster (Pasar, Malaysia), enoki (Pasar, Malaysia), shiitake (Chef, China), white button (Pasar, Holland), and mini portobello (Pasar, Malaysia), and chicken breast (Pasar, Malaysia) were purchased from a local supermarket (NTUC Fairprice, Singapore). Food grade ethanol (Echo Chemical Co., LTD, China) was used for extraction. Methyl undecanoate (C-11) standard, boron trifluoride (BF3), sulfuric acid, hydrochloric acid (HCl), sodium methoxide, methyl tert-butyl ester, sodium citrate dibasic sesquihydrate, GC-grade methanol and hexane were purchased from Sigma-Aldrich (St. Louis, MO, USA) along with petroleum ether (PE) (VWR, Singapore). Digestion tablets (Kjeltabs S-3.5, Foss™) for protein determination was purchased from Nexus Analytics (Singapore).

For the preparation of samples, o-phthaldialdehyde (≥97% for HPLC), 2-mercaptoethanol (≥99.0%), potassium bromide (Purum p.a., ≥99.5%) and boron trifluoride BF3 (10–20% in methanol) were from Sigma-Aldrich (Saint-Quentin Fallavier, France). Purified water (18 MΩ cm) was produced in-house from an Academic MilliQ model water purification unit (Millipore, EMD Millipore Corporation, Billerica, MA, USA). For the preparation of LC mobile phases, acetonitrile (RS for isocratic HPLC, Carlo-Erba Reagents, Val-de-Reuil, France) and methanol (Lichrosolv for HPLC, Merck, Darmstadt, Germany) were used. All other solvents and reagents were of analytical grade.
The mycotoxin primary standard solution of OTA (10 µg/mL in acetonitrile) was from Sigma-Aldrich Chemie (Schnelldorf, Germany). FB1 and FB2 together (50 µg/mL each in an acetonitrile–water mixture) were from Romer labs (Getzersdorf, Austria). Aflatoxins B1, B2, G1 and G2 (250 ng/mL of each in acetonitrile) were purchased from Libios (Bully, France) and T-2 Toxin (100 µg/mL in acetonitrile), HT-2 Toxin (100 µg/mL in acetonitrile), DON (100 µg/mL in methanol) and ZEA (25 µg/mL in methanol) were procured from R-Biopharm (Saint-Didier-au-Mont-d’Or, France).

HPLC grade solvents (hexane, ethanol, and methanol), boron trifluoride (BF₃), NaOH, and NaCl were purchased from Sigma Chemical Co. (St. Louis, MO).

Liver extracts were prepared by grinding a small piece of frozen sample to a fine powder using a ceramic mortar in the presence of liquid nitrogen. Fifty milligrams was transferred to a glass test tube with a teflon-lined screw cap. Twenty microliters of triheptadecanoin (10.0 mg/ml in chloroform) and 40 µl of 1,2-diheptadecanoyl-sn-glycero-3-phosphatidylcholine (5.0 mg/ml in chloroform) were added, and the sample was dried in a stream of nitrogen. The extraction protocol then followed the procedure earlier published by Matyash et al. (17 (link)). Prior to HPLC separation, the samples were redissolved in chloroform-methanol (1:2, v/v). Serum extracts were obtained by centrifugation of fresh blood samples at 1,800 g for 20 min according to Matthan et al. (18 (link)) and were then stored in −80°C until use. Fifty microliters was transferred to a glass test tube with a teflon-lined screw cap. Twenty microliters of triheptadecanoin (10.0 mg/ml in chloroform) was added, the sample was dried in a stream of nitrogen, and lipids were extracted according to Matyash et al. (17 (link)). All solvents were of HPLC grade and purchased from Rathburn Chemicals Ltd. (Walkerburn, Scotland). Lipid standards were purchased from Larodan Fine Chemicals AB (Malmö, Sweden) with purity ≥99%. Boron trifluoride (BF₃, 14% in methanol) was purchased from Sigma Aldrich (Milwaukee, WI).