A RAPID GAS-LIQUID-CHROMATOGRAPHY METHOD FOR THE DETERMINATION OF LACTULOSE AND MANNITOL IN URINE - CLINICAL-APPLICATION IN STUDIES OF INTESTINAL PERMEABILITY

Objective: The purpose of this study was to develop a gas-liquid chrom atography method for the determination of the urinary excretion of two nonmetabolizable sugars (lactulose and mannitol) to estimate the inte stinal permeability. Methods: Two internal standards (alpha-methyl-D-g lucopyranosyde and sucrose) were added to the urine samples prior to d erivatization with the aid of a solution of pyridine, [N, O-bis (trime thylsilyl)]-acetamide and chlorotrimethylsilan. Sample preparation was simpler and faster than in other previous methods acid the four sugar s were resolved within 27 min. Results: The inclusion of internal stan dards reduced the coefficient of variation from 9.44% to 4.78%. The me thod provided better sensitivity, range of analysis, and linearity tha n a previously published HPLC method reducing variances in the recover y of lactulose and mannitol added to urine, The clinical application o f this method was tested in preterm infants fed human milk or cow's mi lk based formula and in breast fed term infants. Conclusion: The metho d described here for the determination of urinary lactulose and mannit ol is more rapid, simpler, and more accurate than other previously pub lished methods.