Simple Sampling Method and Routine Gas Chromatography-Mass Spectrometry Analysis in 13C Breath Tests

Abstract

The 13C-labeled CO2 breath tests are convenient methods for various uses. They can be used to measure gastric emptying rate of solids (1), detect fat malabsorption (2), and evaluate pancreatic lipase activity (3), exocrine pancreatic insufficiency (4), glucose adsorption and utilization (5), liver function control (6), and lactase deficiency (7) with appropriate 13C isotope-labeled compounds. In recent years, the 13C-urea breath test has been used to detect Helicobacter pylori (8). With an appropriate analytical background and the facilities required for the detection or quantification of labeled CO2, the 13CO2 breath test could be widely applied for diagnostic purposes in the medical practice. Although several infrared or mass spectrometric methods (9) are available, the transport of large volumes of gaseous samples to analytical centers as well as storage before measurement involves great problems. Therefore, we have developed a simple method that allows storage of these samples in minimal liquid volume. By this technique, the liberation of isotope-labeled CO2-containing gas occurs immediately before measurements. Because most medical centers are not equipped with expensive and complex isotope-ratio mass spectrometers but generally have a routine low-mass-resolution gas chromatography-mass spectrometry (GC-MS) apparatus, we have also used a simple detection method for 13CO2 by standard GC-MS techniques. Analysis requires only a few minutes, and the method is suitable for selection of 13CO2-containing samples. In our test experiments, we used an air …