Dipotassium hydrogen phosphate k2hpo4

Reagents and chemicals AVM standard was obtained from Hayashi Chemical Co., Inc. (Osaka, Japan). Glucose for stable isotope labeling (U-13 C6, 99%) was obtained from Cambridge Isotope Laboratories, Inc. (MA, USA). Acetonitrile, methanol, n-hexane, ethyl acetate, toluene, formic acid (FA, for HPLC 99%), ammonium formate, soluble starch, sodium chloride (NaCl), ammonium sulfate ((NH4)2SO4), iron(II) sulfate heptahydrate (FeSO4•7H2O), zinc sulfate (ZnSO4), and manganese(II) chloride tetrahydrate (MnCl2•4H2O) were obtained from Fujifilm Wako Chemical Co., Inc. (Osaka, Japan). Glucose, agar powder, dried yeast extract, casein peptone, dipotassium hydrogen phosphate (K2HPO4), calcium carbonate (CaCO3), and magnesium sulfate heptahydrate (FeSO4•7H2O) were obtained from Nacalai Tesque (Osaka, Japan). The purified water used for the mobile phase and sample preparation was obtained from a PURELAB Flex 5 system (ELGA, London, UK). Beef meat samples were commercially purchased from local Japanese grocery stores in 2020 -2021. A stock solution of AVM in Acetonitrile was prepared and stored at -20°C. It was diluted as required using distilled water/Acetonitrile (12/88, V/V).

Acetonitrile, ethyl acetate, chloroform, and tetradecafluorohexane were purchased from Wako Pure Chemical Industries, Ltd. (Osaka, Japan). Triton X-100, hexane, potassium hydroxide (KOH), potassium chloride (KCl), and dipotassium hydrogenphosphate (K2HPO4) were purchased from Nacalai Tesque, Inc. (Kyoto, Japan). 1-Butyl-3-methylimidazolium chloride ([C4mim]Cl) and 1-ethyl-3-methylimidazolium methylphosphonate ([C2mim]MP) were purchased from Tokyo Chemical Industry Co., Ltd. (Tokyo, Japan). Fused silica capillary tubes (inner diameter: 50 or 75 μm) were purchased from GL Science (Tokyo, Japan).