Evaluation of a rapid breath hydrogen analyzer for clinical studies of carbohydrate absorption

A second-generation gas chromatograph for the analysis of H₂ in expired air has been developed. It incorporates a solid-state detector with high sensitivity for H₂ and has a small, internal pump which supplies air as the carrier gas, thus eliminating the need for a large tank of compressed gas for the carrier. A reference gas of known H₂ concentration is, of course, still required. The entire system weighs 6.0kg and is completely portable, requiring only 120 V electric current for use. The instrument has a mean intersample interval of less than 2 min, with H₂ concentration registered on a digital display. The output has a track-hold feature which permits the output, in parts per million H₂, to be retained by the meter so the reading can be verified. The chromatogram can also be recorded on a conventional analog strip-chart recorder. The sensitivity and precision are superior to those of a thermal conductivity H₂ gas chromatograph. Moreover, the rapid response time encourages frequent calibration checks with the reference gas. This analyzer offers significant advantages over previous H₂-measuring systems for breath-analysis tests used both for diagnostic clinical practice and for field studies of nutritional assessment. INCAP Publication No. I-1268 Dr. Solomons is a recipient of a Clinical Investigator Award (1 K08-AM-00715) from the National Institutes of Health (NIH).