Study of Halitosis-Substance Sensing at Low Concentration Using an Electrochemical Sensor Array Combined with a Preconcentrator

Abstract

A method for quantitative detection and discrimination of volatile sulfur compounds (VSCs) using an electrochemical sensor array combined with a preconcentrator was proposed. Halitosis is due to VSCs produced by bacterial metabolism inside the oral cavity. An organoleptic test is typically performed by a dental clinician for the assessment of halitosis, although it is a subjective test. Thus, an objective evaluation of halitosis is required. In this study, it was possible to discriminate among the VSCs such as hydrogen sulfide (H₂S), methyl mercaptan (CH₃SH), and dimethyl sulfide ((CH₃)₂S) over the range of 200ppb to 1000ppb. Moreover, mixture of two VSC vapors (H₂S and CH₃SH) at various mixing ratios were measured. The results indicated that the sensor responses to mixed samples satisfied the linear superposition. The mixture compositions of VSCs were almost correctly obtained from the sensor responses using partial least squares (PLS) regression analysis.