A NEW CONCENTRATION AND DETERMINATION METHOD OF HEXAVALENT CHROMIUM IN WATER BY AN ORGANIC SOLVENT-SOLUBLE MEMBRANE-FILTER

A new concentration and determination method for ppb-levels of hexaval ent chromium ion in water, based on the reaction between chromium (VI) and iodide ion to form triiodide ion and the collection of the ion-as sociate of the triiodide ion with a cation surfactant on an organic so lvent-soluble membrane filter, has been described. The color intensity due to the ion-associate in the resulting solution, obtained by disso lving the filter and solute, is directly proportional to the amount of chromium (VI) in the range 0.2 - 1.2 mu g. Detection limits better th an 0.2 mu g dm(-3) as Cr (VI) can been achieved with a 100-fold enrich ment factor, The diverse components normally present in water do wt in terfere, The proposed method has been applied to the analysis of sever al water samples, such as ground water and waste waters, The recoverie s of the chromium (VI) added to the samples are quantitative, and resu lts found are satisfactory.