Batch-injection stripping voltammetry of metals in fuel bioethanol

This article reports for the first time the application of batch injection analysis (BIA) with anodic stripping voltammetry (ASV) for determination of metals in fuel bioethanol. An aliquot of bioethanol plug (up to 1 mL) is directly injected onto a working (mercury-film) electrode immersed in electrolyte through an electronic micropippete and simultaneously metal deposition occurs. Stripping peaks for cadmium, lead, and copper were obtained at the same voltammetric scan under optimized conditions (electrolyte, deposition time and potential, injected volume, and dispensing rate). The proposed method presented low detection limit (⩽1 μg L−1) for a 90 s deposition time, a linear range between 12.5 and 200 μg L−1, and adequate recovery values (87-109%) for spiked samples. Estimation of the labile fraction of metals in bioethanol samples was also attained. Such remarkable analytical features associated with the portability characteristics of BIA attest the promising application of the proposed method for routine and on-site determination of metals in bioethanol.