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

A simple procedure for the detection of low concentrations of malachite green and crystal violet in water is presented. The dyes were preconcentrated from 1000 ml of water samples with magnetic solid phase extraction using magnetic affinity adsorbent (magnetite with immobilized copper phthalocyanine dye). Due to the magnetic properties of the adsorbent the preconcentration process can also be performed in water samples containing suspended solids. After elution of the captured dyes, their presence in eluates was detected spectrophotometrically. Concentrations of both dyes in the range 0.5–1.0 μg l−1 of water could be reproducibly detected. The dyes can be detected not only in potable water, but also in river ones.