Analusis 28, 217-227 (2000)
DOI: 10.1051/analusis:2000113

Instability of conducting polymer sensors in an electronic nose system

E. Schaller¹, J. O. Bosset¹ and F. Escher<sup>2

1</sup>  Federal Dairy Research Station, CH-3003 Bern, Switzerland
²  Swiss Federal Institute of Technology (ETH), Institute of Food Science, CH-8092 Zürich, Switzerland

(Received December 17, 1999; revised February 14, 2000; accepted February 15, 2000.)

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.

Key words: Electronic nose -- polypyrrole -- conducting polymer -- ethanol.


© EDP Sciences, Wiley-VCH 2000