Abstract: To establish a liquid chromatography-tandem mass spectrometry(LC-MS/MS)for serum uric acid, and to compare LC-MS/MS with clinical routine determination methods. Uric acid-¹⁵N₂ was added as internal standard, serum samples were precipitated with acetonitrile and dried with nitrogen flow. A reversed-phase chromatographic separation was performed on Capcell C18 MGⅢ analytical column by using 5 mmol/L ammonium acetate plus 0.1% acetate acid in water and methanol(90∶10,v/v)as mobile phase. The flow rate was 0.3 mL/min. Uric acid and internal standard were monitored by a negative electrospray ion-tandem mass spectrometry system using ion transitions of 167/124 amu (quantitation) and 167/96 amu (qualitation) for uric acid and 169/125 amu for uric acid-¹⁵N₂. After being validated, the LC-MS/MS was compared with the uricase ultraviolet (UV) method and uricase colorimetric (UC) method. The LC-MS/MS was validated over a concentration range of 30-952 μmol/L. Within-run and between-run precisions were 2.01%-6.23% and 4.55%-8.08%, respectively. The accuracy was 96.5%-103.4%. The retention time of uric acid was 1.5 min, and total run time was 3 min. The linear correlation formulas among LC-MS/MS, uricase UV method and uricase UC method were Y_UV=0.898X_LC-MS/MS +2.15, r=0.978 and Y_UC=0.845X_LC-MS/MS+22.15, r=0.983. The average biases were 1.56%±0.65% between LC-MS/MS and the National Institute of Standards and Technology (NIST) standard reference material and -0.34%-3.05% between LC-MS/MS and correctness verification samples, 2014 from the National Center for Clinical Laboratory. Serum uric acid can be simply and accurately measured by LC-MS/MS. There is good comparability between LC-MS/MS, uricase UV method and uricase UC method.

Key words: Uric acid, Liquid chromatography-tandem mass spectrometry method, Uricase ultraviolet method, Uricase colorimetric method