Spectrophotometric determination of brilliant green in aqueous samples after supramolecular solvent extraction

Brilliant green (BG) is one of the triphenylmethane dyes that has been widely used to color silk and wool in textile industry [1]. BG has also been used in fish farming industry because of its high efficiency in the prevention and treatment of certain fish disease and its low cost [2]. BG dye is toxic and has mutagenic and carcinogenic effects that affect aquatic biota and humans. Due to its carcinogenic properties, the use of BG as veterinary treatment is banned by the USA, European and many other countries [3]. So, there is a serious need to develop a fast, sensitive, inexpensive, and simple method for determining the BG from real samples.In the present study, a simple supramolecular solvent based dispersive liquid-liquid microextraction method was developed for the separation and preconcentration of brilliant green prior to its determination by spectrophotometry. The method is based on the extraction of brilliant green with coacervates made up of decanoic reverse micelles in tetrahydrofuran-water mixture. Sodium dodecyl sulfate was used for the ion-pair formation with brilliant green. The influence of the effective parameters such as pH, type and volume of the extraction solvent, volume of disperser solvent, and sample volume on the extraction of brilliant green was investigated and optimized. Under the optimized conditions, the calibration graph was linear in the range of 1.0-17.5 μg L-1 of BG. The limit of detection (LOD) and limit of quantification (LOQ) were 0.28 μg L-1 and 0.94 μg L-1, respectively. The repeatability expressed as the relative standard deviation for six replicate measurements at 5.0 ng L-1 brilliant green was 3.6%. The method was successfully applied to the extraction and determination of brilliant green in different water and fish farming water samples.