Dispersive Liquid-Liquid Semi-Microextraction of Сu(II) with 6,7-dihydroxy-2,4-diphenylbenzopyrylium Chloride for its Spectrophotometric Determination.

A novel dispersive liquid-liquid semi-microextraction (DLLsME) procedure for copper(II) preconcentration is proposed. The system containing copper(II) and 6,7-dihydroxy-2,4-diphenylbenzopyrylium chloride (DHDPhB), after addition a mixture of chloroform and methanol becomes cloudy and the formation of the organic phase was observed immediately. The optimal conditions of DLLsME were found to be: pH 5, absorption band maximum was 570 nm, 1 cm3 of 1×10-3 mol/dm3ofDHDPhB, and mixed extractant containing 1 cm3 of chloroform and 1 cm3 of methanol. Under optimal conditions, the calibration plot was linear in the range of copper(II) concentration 4.32-65 µg/dm3 and the limit of detection was 1.29 µg/dm3. The rocks and tap water samples were successfully analyzed according to the suggested procedure with RSD no more than 4.9%.