SIA with Voltammetric Detection

SIA has been proposed as an alternative to FIA especially in monitoring of industrial processes where robustness, low reagent consumption, stability, low maintenance, versatility, and automation are essential requirements. There are various review papers describing the fundamentals, potentialities, and limitations of SIA [16, 43, 44, II0-II2]. However the applications in agriculture and food analysis have still presented very few examples using electrochemical detectors, in particular voltammetric sensors. 

Gutes et al. [113] have described an automated procedure based on voltammetric electronic tongue formed by a biosensor array for the determination of glucose in fruit juice samples. Linear sweep voltammetric signals were obtained with high selectivity and artificial neural networks were used as the modeling tool. 

The SIA system in association with amperometric detection using a boron-doped diamond electrode was proposed for the quantification of sulfite in wine samples [114], To prevent interference from sample matrices, a gas diffusion unit was used. A linear range from 0.2 to 20 mg and a detection limit of 0.05 mg 1 were achieved during SOg analysis. 

Exploring the excellent combination between SIA and anodic stripping voltammetry for quantification of metals in river sediment extracts and water samples, different detectors were used as well as the preconcentration step was carried out by deposition of analytes on mercury electrode and bismuth or antimony film electrode [115-117]. Reliable voltammetric signals were obtained since it was possible to reproduce the conditions of charge and mass transport with high precision by reproducible electrode area, stirring, and time control. 

Injang et al. [118] have developed a fast method for the simultaneous determination of Pb , Cd +, and Zn + in herb samples by association of SIA with anodic stripping voltammetry. A bismuth film on the screen-printed carbon nanombes was prepared in situ and used as working electrode. Using a flow rate of 12 pi s low detection limits (0.2 pg 1 for Pb, 0.8 pg for Cd and 11 pg 1 for Zn) were achieved. 

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