Selective methanol detection in adulterated alcoholic beverages using a chemiresistive sensor-embedded analyzer

초록

Methanol poisoning is a global health concern, often caused by counterfeit or improperly labeled alcoholic beverages, particularly in regions with lenient alcohol regulations. Real-time detection is challenging due to the similar structures of methanol and ethanol. This study introduces a real-time methanol analyzer using a proton form of Zeolite Socony Mobil-5 (HZSM-5)-catalyst-coated In2O3 bilayer gas sensor. By dehydrating ethanol into ethylene through the acidic surface properties of HZSM-5, ethanol interference is suppressed without compromising the methanol response. This demonstrates high methanol response (14.6-55.4) and selectivity (6.1-7.0) over ethanol, even at various analyte gas concentrations (20-400 ppm) and high humidity conditions (relative humidity (RH) 80 %). To simplify commercial sensor fabrication, superior methanol-sensing performance was demonstrated using an HZSM-5 and In2O3 composite in the sensing layer. The developed methanol analyzer, incorporating an HZSM-5-coated In2O3 bilayer sensor, enables highly selective methanol detection with negligible interference from ethanol. Under the tested conditions, the analyzer accurately measured the methanol concentration, corresponding to no apparent error, while the commercial analyzer showed a substantial overestimation (error rate: 60 %) due to ethanol cross-sensitivity. This innovative methanol analyzer offers a practical solution for verifying the legal compliance of alcoholic beverages and monitoring methanol concentrations in home and industrial distillation processes.

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