Labostar twf uv 7

Reference pesticide standards (purity >98%) or stock solutions (1000 mg/L) were sourced from Sigma-Aldrich (St, Louis, MO, USA), Dr. Ehrenstorfer (Augsburg, Germany), Wako Pure Chemical Industries (Osaka, Japan), ChemService (West Chester, PA, USA), and Ultra Scientific (North Kingstown, RI, USA). Acetonitrile and methanol (HPLC grade) were purchased from Fisher Scientific (Seoul, the Republic of Korea). Sodium chloride (NaCl, 99.0%) was bought from Samchun (Gyeonggi-do, Korea). Ammonium formate (≥99.0%), formic acid (LC-MS grade), acetic acid (HOAc, ≥99.7%), sodium citrate tribasic dihydrate (Na₃Citrate · 2H₂O, ≥99.0%), sodium citrate dibasic sesquihydrate (Na₂HCitr·1.5H₂O, ≥99.0%), sodium acetate anhydrous (NaOAc, ≥99.0%), and magnesium sulfate anhydrous (MgSO₄, ≥99.5%) were obtained from Sigma-Aldrich. Ceramic homogenizers (2 mm) were obtained from Ultra Scientific. Ultrapure water was prepared in house using LaboStar™ TWF UV 7 (Siemens, Lowell, MA, USA).

VD3, 25(OH)D3, isotopically labeled 6, 19, 19 [d3]-VD3, d3–25(OH)D3, methyl tert-butyl ether (MTBE), formic acid (LC-MS grade), and ammonium formate (≥99.0%) were purchased from Sigma-Aldrich (St. Louis, MO, USA). Methanol, ethanol, and acetonitrile (AcN) were liquid chromatography/mass spectrometry (LC/MS)-grade and purchased from Fisher Scientific (Pittsburgh, PA, USA). Ultra-pure water was prepared with LaboStar™ TWF UV 7 (Siemens, MA, USA).