Quantification of Monosaccharides in Blood and Urine by HPAEC-PAD

This study presents an analytical method for the quantification of glucose, fructose, tagatose, and galactose in plasma, erythrocytes, and urine using high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). The method has been validated with regard to linearity, LOD, LOQ, precision, and recovery over a wide concentration range. In oral glucose, fructose, and tagatose (containing galactose) tolerance tests. The analytical method proved to be suitable and reliable to examine the absorption and excretion of dietary monosaccharides. Postprandial plasma and erythrocyte levels of the four monosaccharides increased within 60 min and decreased to basal levels after 180 min, except for the plasma tagatose levels, which remained elevated. To our knowledge, this is the first time that an uptake of tagatose from plasma into erythrocytes has been shown. The renal excretion of ingested tagatose was only 3.7% within 24 h, while an oral glucose and fructose tolerance test had no influence on the renal excretion of dietary monosaccharides.