Detection of low concentrations of malachite green and crystal violet in water

A simple procedure for the detection of low concentrations of malachite gre en and crystal violet in wa ter is presented. The dyes were preconcentrated from 1000 ml of water samples with magnetic solid phase extraction using m agnetic affinity adsorbent (magnetite with immobilized copper phthalocyanin e dye). Due to the magnetic properties of the adsorbent the preconcentratio n process can also be performed in water samples containing suspended solid s, After elution of the captured dyes, their presence in eluates was detect ed spectrophotometrically. Concentrations of both clues in the range 0.5-1. 0 mug l(-1) of water could be reproducibly detected. The dyes can be detect ed not only in potable water, but also in river ones. (C) 2001 Elsevier Sci ence Ltd. All rights reserved.