Spectrophotometric determination of bisazo dye malachite green in water sample

In this paper, a new spectrophotometric method was established for the determination of malachite green. The optimal pH for the determination of malachite green for the method is 4.0 with a suitable temperature of 35 degrees C. In a pH 4.0 acetic acid-sodium acetate buffer solution medium, the maximum absorption wavelength of malachite green was located at 614 nm. A good linearity is presented over the concentration range of 0-6.0 mu g/mL of malachite green and absorbance at this wavelength. The apparent molar absorption coefficient of the method was 7.43 x 10(4) L/(cm center dot mol) at 614 nm with a detection limit of 0.13 mu g/mL and a quantification limit of 0.43 mu g/mL. Then influences of thirty-three co-existing substances on the determination of malachite green were determined. The inter-day and intra-day relative standard deviation for polluted water sample is 0.60% and 0.83%, respectively. The present method was used for the determination of malachite green in a few kinds of water samples with good precision and accuracy. A rapid and accurate method has been established for the determination of malachite green in water samples.