Development of VOC analyzer using a WO3 thick film based gas sensor

This paper describes a VOC gas analyzer system developed using an original gas sensor and gas chromatography for the detection of aromatic hydrocarbon gases. The sensor is based on a WO₃ thick film where Pd and Pt are applied as catalyst to a limited area of the film to promote sensitivity and improve gas selectivity. The sensor shows extremely high sensitivity to the target aromatic hydrocarbon gases and low sensitivity to interference gases such as ethanol and hydrogen etc., and these features have brought a high performance to the system in conjunction with gas chromatography. The target gases at ppb level can be simply measured by directly injecting only a 10 ml sample into the system without using any sampler to concentrate the sample gas, and the concentrations of the target gases are correctly determined by an original quantitative analysis method incorporated in the system.