indirect determination of cyanide by vortex-assisted liquid-liquid microextraction prior to uv-vis spectrophotometry using methylene blue method

Abstract: cyanide is extremely toxic and hazardous for human beings. the natural generation or accidental release of cyanide from the wastewater of industrial processes such as electroplating, metallurgy, nylon and acrylic plastics production, ore leaching and gold mining, lead to contamination of aquatic environments. the world health organization (who) and the european union have set the maximum permissible level of cyanide in drinking water to 70 and 50 μg l-1 [1, 2], respectively. electrochemical and chromatographic methods have been reported for the accurate and sensitive measurement of cyanide in water samples. in this research, the fes particles are added to cyanide solution then is mixed with stirrer for 10 min. ferrocyanide complex is formed and the result, sulfide ions are produced in solution. the leaching solution was separated through a filter paper from fes particles. sulfide ions reacts with n, n-dimethyl-p-phenylenediamine in the presence of ferric chloride to produce methylene blue. to determine trace amount of sulfide, a pre-concentration method is used. a vortex-assisted liquid-liquid microextraction method along with uv-vis spectrophotometric method based on methylene blue formation reaction for selective and sensitive determination of sulfide ions. methylene blue is extracted into 1,2-dichloroethane organic solvent and measured at the wavelength maximum of 658 nm. the peak height of transient signal was proportional to cyanide concentration and was monitored for quantitative analysis. the influence of various chemical and microextraction relevant parameters has been investigated and the performance of the method optimized. at the optimized conditions, the proposed method successfully detected cyanide, which the detection limit obtained as 0.025 ng ml−1. the effects of several potential interferences have studied. the method was successfully applied to determine cyanide in wastewater (electroplating) and various types of water samples.