Analysis of concomitant O-18 in C-13-urea

The C-13-urea breath test by infra-red absorption or mass spectra has been extensively used to detect Helicobacter pylori infection. However, commerci ally available C-13-urea contains higher O-18, compared to natural urea. It is evidently important for this diagnosis to investigate the C-18-isotope effect on infra-red absorption or mass spectra, based on the quantitative a nalysis of O-18 in C-13-urea. For this purpose, a new analytical method usi ng mass spectroscopy has been established to deter mine O-18 abundance in u rea.