Simultaneous gas-chromatographic measurement of rhamnose, lactulose and sucrose and their application in the testing gastrointestinal permeability

Background: As it is important to test gastric and intestinal permeability simultaneously in gastrointestinal disorders such as Celiac disease, we developed a gas-chromatographic (GC) method to estimate rhamnose (L-rh), lactulose (Lacl) and sucrose (Suc) in urine. Methods: The method is based on the use of alditol acetate derivatives giving a lower number of GC peaks than reducing sugars do. Acetate derivatives are more stable and less expensive than GC silylates and keep the flame-detector cleaner. We checked the chemical stability of alditol acetates by verifying the reproducibility of the standard curve of a sugar derivative sample which had been stored for 2 months at -20°C. Results: The calibration proved linear over the range 0.1-1 μg of sugar injected. Analytical sugar recovery was 88%±19.4% (mean±S.D.) for rhamnose, 105%±7.4% for sucrose and 102%±2.4% for lactulose. Mean within-day precision (CV) was 7.7% for rhamnose, 5.7% for sucrose and 1.9% for lactulose, and between-day (CV) was 6. 7% for rhamnose, 3.9% for sucrose and 1.6% for lactulose. The rhamnose, lactulose and sucrose as the lactulose/rhamnose ratio clearly differentiated 25 healthy controls from 36 patients with active gluten-sensitive enteropathy. Conclusions: A fast, reliable and cheap gas-chromatographic method is presented here to evaluate gastric and intestinal permeability. © 2003 Elsevier B.V. All rights reserved.