Novel colorimetric sensor for oral malodour.

Area of Science:

• Biochemistry
• Analytical Chemistry
• Biomedical Engineering

Background:

• Oral malodour is primarily caused by volatile sulfur compounds (VSC).
• Accurate quantification of VSC is crucial for diagnosing causes and monitoring treatments for bad breath.
• Existing quantitative tools can be expensive or complex for widespread use.

Purpose of the Study:

• To develop an objective, cost-effective, do-it-yourself colorimetric sensor for quantifying oral malodour.
• To assess the sensor's suitability for detecting hydrogen sulphide (H2S) at levels relevant to human breath.

Main Methods:

• A colorimetric sensor was designed using an iodine sensing solution and starch indicator.
• A gas sampling unit collected a known volume of mouth air for analysis.
• Iodine depletion by H2S was measured colorimetrically using a photometric detector.

Main Results:

• The sensor demonstrated a detection limit of 0.05 µg L⁻¹ for H2S, suitable for healthy individuals and halitosis patients.
• VSC levels in healthy volunteers ranged from 0.2–0.4 µg L⁻¹.
• High correlation (R²=0.934) was observed between the sensor and a halimeter.

Conclusions:

• The developed portable sensor provides a cost-effective and objective method for oral malodour quantification.
• The sensor shows significant potential as a clinical evaluation tool for assessing bad breath.
• Ease of laboratory fabrication makes the sensor accessible for research and clinical applications.