Ammonium bicarbonate lc ms grade

All the chemicals used in the preparation of the background electrolyte (BGE) and the rest of solutions were of analytical reagent grade or better. Water (LC-MS grade), ammonium acetate (NH4Ac, ≥99.9%), ammonium bicarbonate (LC-MS grade), DLdithiothreitol (DTT, ≥99.0%) and iodoacetamide (IAA, ≥98.0%) were purchased from Sigma-Aldrich (St. Louis, MO, USA). Acetic acid (HAc, glacial), formic acid (HFor, 99.0%), ammonia (25%) and sodium hydroxide (≥99.0%) were supplied by Merck (Darmstadt, Germany). iodoacetamide (IAA, ≥98.0%) was provided by Fluka (Buchs, Switzerland). Acetonitrile (≥99.9%) was purchased from Panreac (Castellar del Vallès, Spain). 2-propanol (≥99.9%) was supplied by Scharlau (Sentmenat, Spain).
Free trypsin (sequencing grade modified trypsin) and particles with immobilized trypsin (immobilized trypsin) were provided by Promega (Madison, Wisconsin, USA). β-LG (~90%, PAGE), α-CSN (>70%), β-CSN (>90%) and κ-CSN (≥80%) were purchased from Sigma-Aldrich. An Escherichia coli cell lysate (E. coli positive control whole cell lysateexpressing 6X His tag protein) was supplied by Abcam (Cambridge, UK).

LC/MS-grade methanol, acetonitrile, isopropanol, formic acid, ammonium acetate and ammonium hydroxide were purchased from Fisher Scientific (Fair Lawn, USA). LC/MS-grade ammonium bicarbonate and LC-grade methyl-tert-butyl-ether (MTBE) were purchased from Sigma-Aldrich Co. (St. Louis, USA). Isotopic internal standards were purchased from Cambridge Isotope Laboratories Inc. (Tewksbury, USA) and Toronto Research Chemicals (Toronto, Canada). A lipid mixture of SPLASH LIPI-DOMIX isotopic internal standard was purchased from Avanti Polar Lipids (Alabama, USA). Ultrapure water (18.2 MO cm) was prepared with an in-house Milli-Q Purified Water system (Merck KGaA, Darmstadt, Germany).