Breath odor evaluation by detection of volatile sulfur compounds – correlation with organoleptic odor ratings

Background:  Detection of oral volatile sulfur compounds (VSC) by gas chromatography (GC) is a widely used method for evaluating breath odor. Air aspirated from the mouth is injected into the GC column for analysis. To eliminate discrepancies caused by variations in operator sampling or injection techniques, a new GC system designed to aspirate breath samples directly into the GC was developed.
Objective:  A clinical study was performed to compare this new automated breath-sampling GC system to organoleptic evaluation by two trained odor judges.
Methods:  A randomized, two-cell, double-blind, parallel design was used in which subjects were tested before and 3 h after using either a mouthrinse containing zinc or a matching placebo rinse. Thirteen subjects used the zinc mouthrinse, and 12 used the placebo. Subjects with a wide range of VSC levels were studied. The average organoleptic ratings for each subject at each time-point were compared with the average VSC measurements made with the GC, and Pearson product–moment correlation coefficients between the corresponding GC and organoleptic measurements were determined.
Results:  The correlation between the GC and organoleptic assessment methods were highly significant ( P  ≤ 0.001) for: total VSC, 0.65; H₂S, 0.63; CH₃SH, 0.61; and (CH₃)₂S, 0.46. The correlation between the two judges was also highly significant (0.823, P  < 0.001).
Conclusion:  These results demonstrate the utility of the automated GC method for evaluating breath odor.