Gas chromatographic determination of hydroxyproline in urine hydrolysates

A simple and specific method for the determination of hydroxyproline in urine hydrolysates has been described. Hydroxyproline was converted into its N-isobutyloxycarbonyl methyl ester derivative without elaborate cleanup, which was analyzed by gas chromatography. Hydroxyproline was clearly separated from other urinary constituents on a 0.60% FFAP on dimethyldichlorosilane-treated Gas-Chrom P column. Kainic acid was used as the most convenient internal standard available. The relative standard deviations of peak height ratios were 1.15--2.51% at the 10--150 microgram levels. Percent recoveries of hydroxyproline added to urine hydrolysates ranged from 98.8 to 107.3%.