1200 series isocratic hplc pump

Metabolome analysis was performed as previously described^{25 (link)}. Frozen collected samples were thawed and centrifuged at 13,000×g for 5 min at 4 °C. The supernatant was transferred to a 5-kDa-cutoff filter (Human Metabolome Technologies, Tsuruoka, Japan) to remove proteins of sizes greater than 5 kDa. Prior to CE-TOFMS analysis, a 45 µL aliquot of the filtrate was added to 5 µL of Milli-Q water containing reference compounds (200 mmol/L each of methionine sulfone, D-camphor-10-sulfonic acid, 3-aminopyrrolidine, and trimesic acid). CE-TOFMS-based metabolome profiling was performed using an Agilent 7100 Capillary Electrophoresis system (Agilent technologies, Waldbronn, Germany), an Agilent 6224 TOF LC/MS system (Agilent technologies, Santa Clara, CA), an Agilent 1200 series isocratic HPLC pump, a G1603A Agilent CE-MS adapter kit, and a G1607A Agilent CE-electrospray ionization (ESI)-MS sprayer kit. In anionic metabolites analysis, ESI sprayer was replaced with a platinum needle instead of an initial stainless-steel needle^{25 (link)}. Other conditions of the CE–ESI–MS sprayer were the same as received. The metabolome analysis conditions were the same as those described elsewhere^{9 (link),26 (link)–28 (link)}. Data analysis were performed using the metabolome analysis software MasterHands as previously described^{29 (link)}.