2014 Volume 31 Issue 1 Pages 27-
The simultaneous determination of As(III) and As(V) in aqueous solution based on the acidic permanganate and luminol chemiluminescence (CL) detection systems have been applied to a split microfluidics flow injection (µFI) with dual-channel manifolds at rapid sampling rate. The µFI-CL system consisted of two halves of micro-conduit platforms, which ran on a simple device made from small pieces of the laser engraved polymethylmethacrylate (PMMA) and polydimethylsiloxane (PDMS). The specific CL reaction for As(III) was produced by the oxidation of acidic potassium permanganate in the presence of sodium hexametaphosphate media, while the CL reaction for As(V) was generated based on the oxidation of luminol with a vanadomolybdoarsenate heteropoly acid (AsVMo-HPA) complex in an alkaline solution. The µFI method involved the injection of the mixed standard solution into an acid carrier stream where it was then splitted and merged with the reagent solutions of each reaction systems on a spiral-designed microfluidic platform. The solution mixtures were passed through each spiral flow channel, where the CL intensity of both resulting reaction mixtures were measured with two photomultiplier tubes. Linear calibratons for As(III) and As(V) were established over the concentration ranges of 20-60 µg L-1. The limits of detection (signal-to-noise ratio of 3) of As(III) and As(V) were found to be 4 µg L-1 and the limits of quantification (signal-to-noise ratio of 10) were found to be 10 µg L-1, respectively. The proposed procedure was successfully applied for the determination of As(III) and As(V) in ground water samples.
