# Quantification of Monosaccharides in Blood and Urine by HPAEC-PAD

## TL;DR

The paper introduces a reliable method to measure specific sugars in blood and urine, revealing how they are absorbed and excreted after consumption.

## Contribution

The first demonstration of tagatose uptake into erythrocytes and its low renal excretion.

## Key findings

- Plasma and erythrocyte levels of monosaccharides increased within 60 minutes after consumption.
- Plasma tagatose levels remained elevated even after 180 minutes.
- Only 3.7% of ingested tagatose was excreted by the kidneys within 24 hours.

## Abstract

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.