An Environmental Friendly Procedure for Photometric Determination of Hypochlorite in Tap Water Employing a Miniaturized Multicommuted Flow Analysis Setup

摘要

A photometric procedure for the determination of ClO~(?) in tap water employing a miniaturized multicommuted flow analysis setup and an LED-based photometer is described. The analytical procedure was implemented using leucocrystal violet (LCV; 4,4′,4′′-methylidynetris (N,N-dimethylaniline), C_(25)H_(31)N_(3)) as a chromogenic reagent. Solenoid micropumps employed for solutions propelling were assembled together with the photometer in order to compose a compact unit of small dimensions. After control variables optimization, the system was applied for the determination of ClO~(?) in samples of tap water, and aiming accuracy assessment samples were also analyzed using an independent method. Applying the paired t -test between results obtained using both methods, no significant difference at the 95% confidence level was observed. Other useful features include low reagent consumption, 2.4? μ g of LCV per determination, a linear response ranging from 0.02 up to 2.0?mg?L~(?1)??ClO~(?), a relative standard deviation of 1.0% ( n = 11) for samples containing 0.2?mg?L~(?1)??ClO~(?), a detection limit of 6.0? μ g?L~(?1)??ClO~(?), a sampling throughput of 84 determinations per hour, and a waste generation of 432? μ L per determination.