Chemically-sensitive resistors have been developed that allow rapid detection of an important class of compounds, biogenic amines, at levels of 1−10 parts per trillion in ambient air. The materials are composites of a conducting organic polymer, the emeraldine salt of polyaniline, with particles of another conducting phase, carbon black. The resistance response of an EM−DBSA(1:0.5)/CB (80:20) detector exposed to water (a), acetone (b), methanol (c), ethyl acetate (d), and butanol (e) is approximately a factor of a million smaller than that to butylamine (f)
