Detection of sialuria by cation-exchange high-performance liquid chromatography

A simple and selective method for the detection of sialuria by high-performance liquid chromatography is described. The urine sample (2 ml) is purified using a C18 cartridge or ion-exchange chromatography, and free N-acetylneuraminic acid is separated on an Aminex HPX-87 cation-exchange column using 3 mM sulphuric acid as the mobile phase. The retention time of N-acetylneuraminic acid is ca. 8 min and the detection limit ca. 1 mumol/l. The within-day coefficient of variation is less than 4.9% and the day-to-day coefficient of variation is less than 5.6%. The method was tested on twenty normal individuals and four sialuria patients.