Polyvinylidene fluoride pvdf syringe filters

Formalin (37% aqueous formaldehyde solution) and sodium bicarbonates were purchased from Sigma, Leica, Microsystem, and Germany. HPLC grade methanol was obtained from Merck (Darmstadt, Germany). LCMS-grade acetonitrile was purchased from J. T. Baker (Philipsburg, NJ, USA). Deionized water was acquired using Milli-Q system (Merck, Darmstadt, Germany) at resistivity of > 18.2 MΩ cm. Reference mass solution containing 5.0 mM of purine and 2.5 mM of Hexakis [1H,1H,3H-tetrafluoropropoxy] phosphazine, was procured from Agilent Technologies (Santa Clara, CA, USA). LCMS-grade formic acid (HCOOC) was acquired from Fisher Scientific (Fair Lawn, NJ, USA). Polyvinylidene fluoride (PVDF) syringe filters with 0.22 µm pore size and 13 mm diameter were purchased from Merck (Darmstadt, Germany).

A mixture of hexane and ethyl acetate was used for column preparation and fractionation. Silica gel (SiO₂) and normal phase thin layer chromatography plate were obtained from Merck, Germany. Developed TLCs were visualized using 5 per cent molybdophosphoric acid in ethanol was purchased from Nacalai, Japan. Formalin (37 per cent aqueous formaldehyde solution) was bought from Sigma, Leica, Microsystem (Darmstadt, Germany), Methanol (HPLC grade) was purchased from Merck (Darmstadt, Germany). LCMS-grade acetonitrile was obtained from J. T. Baker (Philipsburg, NJ, USA). Polyvinylidene fluoride (PVDF) syringe filters (0.22 µm pore size and 13 mm diameter) were bought from Merck (Darmstadt, Germany). Deionized water was acquired via a Milli-Q system (Merck, Darmstadt, Germany) at a resistivity of >18.2 MΩ·cm. Reference mass solution containing 5.0 mM of purine and 2.5 mM of Hexakis [1H,1H,3H-tetrafluoropropoxy] phosphazine, was procured from Agilent Technologies (Santa Clara, CA, USA). LCMS-grade formic acid (HCOOC) was acquired from Fisher Scientific (Fair Lawn, NJ, USA).