Cyanides and hydrogen cyanide. amongst the most toxic chemicals are used in various industries (1. 2).
Cyanides act directly on the central nervous system and are also absorbed through skin. The maximum tolerable concentration of cyanide is 5 ms/mJ in air calculated as CN-(1). The WHO recommends that water containing more than 0.01 ppm of cyanide is harmful for common public uses ( 3 ) .
Various instrumental methods are reported for its determination (4-9). Most common spectrophotometric methods are based on Konig reaction (10) developped by Alridge (7) and Epstein ( 8 ) .
The reagents used have their own merits and demerits (8, 9. 11. 12). In the proposed method cyanide is determined by conversion into cyanogen bromide followed by its reaction with pyridine.
The clutaconic aldehyde so formed is coupled with phloroglucinol forming a red violet dye measured at 540 nm. The optimum reaction conditions for full colour development have been studied and applied for the determination of cyanide in waste water and biological fluids.
EXPERIMENTAL Apparatus
A Carl-Zeiss spekol and calibrated glasswares were used.