Appropriate sample bags and syringes for preserving breath samples in breath odor research: a technical note

It is now generally accepted that the volatile sulfur compounds (VSCs) hydrogen sulfide, methyl mercaptan and dimethyl sulfide are the main contributors to halitosis when of oropharyngeal origin. The VSCs hydrogen sulfide and methyl mercaptan are the major causes of bad breath in oral malodour whereas dimethyl sulfide is generally the major cause of bad breath in extra-oral halitosis. To facilitate research in the field of halitosis, it is highly advantageous to be able to preserve breath samples for longer periods of time before measurement of the VSCs, e.g. for sampling patients at home or when studying a large cohort of patients where an immediate measurement of the VSCs is not possible. After testing numerous sample bags, ultimately the foil balloons, coated inside with the synthetic polymer polyethylene, were the preferred ones. All the VSCs in breath remained quite stable for at least 3 days in these balloons. Besides the sampling bags, the use of an appropriate syringe for sampling mouth air and for injecting samples in e.g. a gas chromatograph is also of great importance. Usually, syringes with a rubber barrel seal are used. However, some rubbers quickly adsorb the VSCs in breath. When preserving breath samples for longer periods, the rubber also releases VSCs, especially methyl mercaptan. It was also found that these syringes release a compound which interferes with dimethyl sulfide, when using gas chromatographic measurements with the OralChroma. We now use all-plastic syringes (B/Braun Injekt), made of polypropylene and polyethylene, in which the VSCs in breath remain quite stable for at least 9 h.