There are 700 (Velde V, 2009) or 3481 (Phillips M, 1999) gases in the breath but Halimeter detects only one gas while Oral chroma detects 3 gases only.
I always use MX6 (IndSci) portable gas detector. Thus I can read more than 100 gases in oral air. I have developed a measurement protocol to separetly read gas composition of oral-nasal-alveolar air by using MX6. See below paper:
(Aydin M. Özen ME. Kirbiyik U, Evlice B, Ferguson M, Uzel I. A new measurement protocol to differentiate sources of halitosis. Acta Odontol Scand., 2016, 11:1-5 DOI: 10.3109/00016357.2016.1163732 )