Adenosine 5 monophosphate sodium salt

Cytosine (100% purity), uracil (100% purity), guanine (99% purity), adenine (100% purity), hypoxanthine (100% purity) standards, and 5-methyl cytidine (purity ≥ 99%), 1-methylguanosine (100% purity), adenosine 5′-monophosphate sodium salt, cytidine 5′-monophosphate disodium salt, guanosine 5′-monophosphate disodium salt, uridine 5′-monophosphate disodium salt, inosine 5′-monophosphate disodium salt, 5′thymidylic acid disodium salt (purity ≥ 99%), nuclease (nuclease P1), pyrophosphatase (nucleotide pyrophosphatase), and phosphatase (bacterial alkaline phosphatase) reagents were purchased from Sigma.

High performance liquid chromatography (HPLC)-grade methyl tert-butyl ether (MTBE) and methanol (MeOH) as well as n-hexane were procured from Merck (Darmstadt, Germany). The stock solutions of the standards were prepared at a concentration of 1 mg/mL in MTBE. All stock solutions were stored at −20°C and diluted with MTBE to working solutions prior to analysis. MilliQ water (Millipore, Bradford, United States) was utilized in all experiments. A 15% boron trifluoride solution in MeOH was obtained from RHAWN (Shanghai, China). All pure standards were acquired from Sigma-Aldrich (St. Louis, MO, United States), including inosine 5′-monophosphate disodium salt (5′-IMP), guanosine 5′-monophosphate disodium salt (5′-GMP), adenosine 5′-monophosphate sodium salt (5′-AMP), cytidine 5′-monophosphate disodium salt (5′-CMP), uridine 5′-monophosphate disodium salt (5′-UMP), amino acids standards, bis (trimethylsilyl) trifluoroacetamide (BSTFA), glucose, quercetin, sodium chloride, ergothioneine and phosphate. Bovine serum albumin (BSA) standard solution was purchased from Sangon Biotech (Shanghai) Co., Ltd. (Shanghai, China).