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

Abstract EN

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), C25H31N3) 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 μg 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 μg L−1 ClO-, a sampling throughput of 84 determinations per hour, and a waste generation of 432 μL per determination.