Development of a compact and simple gas chromatography for oral malodor measurement

J Periodontol. 2006 Jul;77(7):1142-7. doi: 10.1902/jop.2006.050388.


Background: Volatile sulfur compounds (VSCs) in oral air are the only type of gases correlated with the strength of oral malodor. We developed a compact and simple gas chromatograph (GC) equipped with a newly invented indium oxide semiconductor gas sensor (SCS) for measuring the concentrations of VSCs in mouth air. We have assessed the correlation between measurements with a GC-SCS and those with a regular GC.

Methods: Oral air samples from randomly selected volunteers were analyzed with both a GC-SCS and a GC with a flame photometric detector (FPD), which is specific to VSCs, and GC-SCS measurements were compared to those obtained by GC-FPD. Subsequently, oral air samples before and after mouthrinsing with 5% ethanol mouthwash were analyzed to determine the effect of ethanol on VSC measurements by GC-SCS.

Results: There were strong correlations between VSC concentrations determined using these two gas chromatography methods (hydrogen sulfide, R=0.821, P<0.0001; methyl mercaptan, R=0.870, P<0.0001; and dimethyl sulfide, R=0.770, P<0.0001). Although GC-SCS can differentiate ethanol and VSCs in oral air samples after mouthrinsing, GC-SCS measurements demonstrated higher values than those obtained by GC-FPD; however, this discrepancy improved over time due to the reduced effect of ethanol.

Conclusion: The results suggest that GC-SCS may be useful for the diagnosis of halitosis.

Publication types

  • Comparative Study
  • Evaluation Study

MeSH terms

  • Adolescent
  • Adult
  • Biosensing Techniques / instrumentation
  • Breath Tests / instrumentation*
  • Chlorides
  • Chromatography, Gas / instrumentation*
  • Ethanol
  • Female
  • Halitosis / diagnosis*
  • Humans
  • Indium
  • Male
  • Middle Aged
  • Mouthwashes
  • Photometry / instrumentation
  • Reproducibility of Results
  • Semiconductors
  • Statistics, Nonparametric
  • Sulfur Compounds / analysis*
  • Zinc Compounds


  • Chlorides
  • Mouthwashes
  • Sulfur Compounds
  • Zinc Compounds
  • Indium
  • Ethanol
  • indium oxide
  • zinc chloride