A robust LC-MS/MS method to measure 8-oxoGuo, 8-oxodG, and NMN in human serum and urine

To establish and validate a robust LC-MS/MS method for simultaneously measuring 8-oxoGuo, 8-oxodG, and NMN in serum and urine to evaluate the oxidative stress status.A Waters TQ-XS triple quadrupole mass spectrometer system coupled with an Acquity UPLC Primer HSS T3 column was chosen. The clinical performance was verified according to the CLSI C62-A and EP-15 guidelines. Furthermore, matched serum and urine samples from 22 apparently healthy check-ups, 20 patients with atherosclerosis, and 18 individuals with dementia were evaluated.The recovery for serum 8-oxoGuo, urine 8-oxoGuo, serum 8-oxodG, urine 8-oxodG, serum NMN, and urine NMN was 88.8-112.4%, 102.4-114.1%, 88.5-107.7%, 94.9-102.6%, 98.4-108.9%, and 88.5-108.6%, respectively. Based on the inter-assay results, total coefficient of variation, matrix effect, and carryover, the LC-MS/MS method was deemed robust. The limit of quantification was 0.017, 0.018, and 0.150 nmol/L for 8-oxoGuo, 8-oxodG, and NMN, respectively, which are suitable for accurate measurements in human serum and urine samples. Higher 8-oxoGuo and 8-oxodG levels and lower NMN levels, indicative of significantly higher oxidative stress status, were found in patients with dementia compared to healthy subjects.We established and validated a robust LC-MS/MS method to simultaneously measure 8-oxoGuo, 8-oxodG, and NMN in serum and urine.