Gas chromatographic quantitation of breath hydrogen and carbon monoxide for clinical investigation in adults and in children.

A simple and suitable method of breath sampling and the gas chromatographic determination of H2 and CO in breath of children as well as of adults are described. The analytical system allows the measurement of concentrations of H2 and CO as low as a few ppm. The proposed method of breath collection (tedlar bag with low resistance valve face mask) appears particularly useful for long storage purposes, because it eliminates the need for additional manipulations and the possible associated sample dilution. Normalization of H2 breath amounts to internal standard O2 to obtain reliable and precise measurements is particularly useful in non-collaborating patients whose observed H2 peak values increase by 15% after the correction. The overall procedure is fast, inexpensive and accurately recognizes adult or children lactose malabsorbers as well as subjects exposed even to low levels of CO.