Flow injection-gas diffusion technique for the determination of cyanide in waters
Written by sctunisie no commentsA rapid and simple flow injection system with gas diffusion separation and spectrophotometric detection is described for the determination of acid dissociable cyanide in natural and wastewater samples. The proposed method is based on the diffusion of cyanide (as hydrogen cyanide) through a microporous PTFE membrane wall from a hydrochloric acid donor stream into a bromothymol blue acceptor stream. The transferred cyanide was then reacted with bromothymol blue and the changes in the reagent colour was monitored spectrophotometrically at 630 nm. The working conditions of the flow injection system (donor stream concentration, acceptor stream concentration and pH, sample loop volume, flow rates...etc.) were optimised. The calibration graph is linear from 1 to 25 μgml-1 cyanide (R2 = 0.998), the detection limit is 0.5 μgml-1, the sampling rate is 25 samples h-1 and the precision was 1.85% RSD. The method is simpler and quicker than other published flow injection methods.
L. Monser, N. Adhoum
Cyanide, Bmmothymol blue, Flow injection, Gas diffusion, Spectophotometry
Pages 1607-1613
