The enzymatic spectrofluorimetric determination of uric acid in microsamples of plasma by using p-hydroxyphenylacetic acid as a fluorophor.

A sensitive spectrofluorimetric micromethod for the determination of uric acid is presented together with its application to human and rat plasma. The method is based on the reactions or uricase and peroxidase coupled with p-hydroxyphenylacetic acid as a fluorophor. There is a very wide range of proportionality between the concentration of uric acid and the increase of fluorescence intensity. 10 ng of uric acid is still determinable. At most 25 mul of human or 50 mul of rat plasma is sufficient to obtain the accurate valve of endogenous plasma uric acid concentration. The uric acid levels of normal human and rat plasma measured by present method were within the ranges of concentrations previously reported. A comparative study of this method with a standard assay method is also presented.