PORTABLE BATTERY-POWERED FLOW-INJECTION ANALYZER FOR VOLATILE ALCOHOLS USING SEMICONDUCTOR GAS SENSORS

The response characteristics of Taguchi TGS812 and TGS824 type semicon ductor gas sensors were evaluated for flow injection monitoring of alc ohol concentrations in liquid samples. The detection method was based on the head space analysis of vapour above aqueous samples containing ethanol. A low cost, hand-held monitor has been developed for this app lication in which an air carrier stream is pumped through a twin senso r cell. Different sensitivities to aqueous ethanol samples were observ ed at each sensor. Analysis of commercial liquor samples such as beers , wines and liqueurs showed a correlation coefficient as high as 0.999 9 in comparison with gas chromatography analysis. This system is there fore applicable as a portable, hand-held flow injection monitor for pr ocess control during production and for monitoring the quality of prod ucts containing ethanol.