Instability of conducting polymer sensors in an electronic nose system

Abstract

A solution of 1 mL/L ethanol in water was used to study the repeatability of measurements performed with an electronic nose equipped with 12 conducting polymers based on polypyrrole. The sensor responses exhibited a poor repeatability independently of whether synthetic air or nitrogen was used as carrier gas. The responses varied from one day to the next as well as from one hour to the next. The variations in the baseline resistances, which were also examined, did not help to explain the observed instability. The variations in sensor response could however, be partly explained by a temperature fluctuation of the sensor module. A correction for the temperature changes halved the scatter of the measurements.