The in situ technique of aqueous binding concentration and diffusion for measurements of arsenate concentrations in lake waters.

Arsenic contaminations in waters are concerned worldwide. This research was to examine an in situ method of aqueous binding concentration and diffusion (ABCD) technique with an aqueous solution of metal immobilized polycationic polymer (MIP) as a binding phase and a dialysis membrane as a diffusive layer to pre-concentrate trace arsenate in lake waters. Although the maximum binding capacity of arsenate to MIP was influenced by the presence of anions in water, the binding phase was capable of pre-concentrating arsenate in lake water. This in situ pre-concentration technique was combined with light emitting diodes (LED) for semi-on line detection of trace arsenate in waters. The system was eventually validated in lake waters in lab and in natural lake waters in China. In this work, new colorimetric method for detection of arsenate in the binding phase has been developed to minimize the potential spectra interferences of silicates, phosphates and other oxyanions. Potassium iodide was used to reduce arsenate to arsenite before the solution was mixed with the colour generation reagent of RhodamineB.