In situ bismuth-film electrode for square-wave cathodic voltammetric detection of pendimethalin at nanomolar level

An in situ plated bismuth-film electrode (BiFE) was used for the study of the herbicide pendimethalin. A single peak was observed by cyclic voltammetry at −0.520 V associated with the reduction of pendimethalin in HCl solution at pH 3.0. Square-wave cathodic voltammetry (SWCV) was used for the analytical procedures after the preparation of the BiFE using 10.0 μmol L−1 Bi(III) for 80 s at −0.250 V. A peak current at −0.585 V related to the reduction of the herbicide was obtained, which increased linearly with the pendimethalin concentration in the range of 0.3 to 1.0 μmol L−1. The limit of detection attained was 37.0 nmol L−1. The sensor prepared in situ was applied for the determination of pendimethalin in simulated samples of tap water and sea water with satisfactory results being obtained compared with the UV–vis spectroscopy technique. In addition, pendimethalin was spiked and determined at nanomolar level in samples of water collected from a local river. The recovery values for such experiments were between 93% and 96%.