Monitoring hydrogen sulfide in simulated breath of anesthetized subjects

- We applied negative ion APCI mass spectrometry to the quantification of simulated breath containing air, water vapor, N2O and CO2.
- We added CHCl3 to mimic the influence of halocarbons associated with the breath of anesthetized subjects.
- Both SO2− and SO3− were observed to be sensitive to H2S down to about 1 ppt (trillion). The observed ratio of [SO2−] to [SO3−] was found to be the most useful monitor of H2S.
- SH− was found to be suppressed by CO2 and so unsuitable for H2S quantification in breath.