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An array of chemiresistors based on conducting polymers was assembled for the differentiation of coconut oil products. The chemiresistor sensors were fabricated through the potentiostatic electrodeposition of polyaniline (PANi), polypyrrole (PPy) and poly(3-methylthiophene) (P-3MTp) on the gap separating two planar gold electrodes set on a Teflon substrate. The change in electrical resistance of the sensors was measured and observed after exposing the array to the headspace of oil samples. The sensor response was found rapid, reversible and reproducible. Different signals were obtained for each coconut oil sample and pattern recognition techniques were employed for the analysis of the data. The developed system was able to distinguish virgin coconut oil (VCO) from refined, bleached & deodorised coconut oil (RBDCO), flavoured VCO, homemade VCO, and rancid VCO. [ABSTRACT FROM AUTHOR]

A reduced graphene oxide/chitosan (rGO/Chi) nanocomposite film for chemoresistive trimethylamine sensing was prepared by solution-phase mixing and deposited on nylon membrane via vacuum assisted self-assembly (VASA) method. The film was analysed using Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The electrical property of the prepared films were measured by four-point probe measurement. Using 0.40% volume fraction (v.f) it was exposed to trimethylamine vapour and its electrical resistance quickly changed. The composite film sensor exhibited linear range from 23 to 230mg/L (r 2 = 0.9774) and the calculated limit of detection was 20.56mg/L. It exhibited a repeatable response to trimethylamine gas. [ABSTRACT FROM AUTHOR]