Fungicide residue identification and discrimination using a conducting polymer electronic-nose
The identification of fungicide residues on crop foliage is necessary to make periodic pest management decisions. The determination of fungicide residue identities currently is difficult and time consuming using conventional chemical analysis methods such as gas chromatography-mass spectroscopy. Different fungicide types produce unique electronic aroma signature patterns when headspace volatiles are analyzed using a multi-sensor array within an electronic–nose device. The advantage of electronic-nose sensor devices over conventional methods is that fungicides may be rapidly identified even in the presence of complex plant volatile organic compounds derived from crop foliage that may be present in the headspace mixture. New methods were developed for a conducting polymer type electronic nose device, the Aromascan A32S with a 32-sensor array, to accurately identify and discriminate between fungicide residues types in vitro. The A32S electronic nose distinguished between nine of eleven fungicide types, providing correct identification determinations at frequencies ranging from 84-98%. The distribution of aroma class components, defined by the principal aroma elements detected for each fungicide type analyzed, was determined providing some indications of chemical relatedness between different fungicide aroma classes. The A32S electronic-nose device was capable of providing effective identification and discrimination determinations of most fungicide residue types tested in vitro and has strong potential feasibility for making e-nose fungicide residue determinations on plant (crop) surfaces in the field.