Plasma uric acid: mass spectrometric method for control and comparison of intra- and interlaboratory studies

We propose a preliminary study for the utilization of isotope dilution and mass fragmentography for the measurement of plasma uric acid. Using stable isotopes it is possible to measure this compound in comparison with the molecule labelled with three 15N atoms (1,3,9). We achieved the determination at the molecular peak. A linear calibration curve is obtained from standard solutions between 0 and 600 mumol/l. The method has good precision and the results obtained with different quality control materials demonstrate the need for better accuracy. This method could, after more detailed studies, be a good candidate for a definitive method.