Spectrophotometric Determination of Cyanide and Hydrogen Cyanide Using p-Amino benzoic Acid as a New Reagent and Its Application in Steel Industries

Abstract

A new reagent system is proposed for the determination of cyanide and
hydrogen cyanide. Cyanide is reacted with bromine and pyridine to form
glutaconic aldehyde, which is then condensed with p-aminobenzoic acid
to give a yellow orange dye extractable in n-butanol. Beer's law is obeyed
over a concentration range of 0.02-0.2 ppm of cyanide at 410 nm. The
molar absorptivity and Sandell's sensitivity were found to be
1.3 x 10⁴ L mol^-1cm^-1, and 0.002  μg cm^-1 respectively. The analytical
parameters have been optimised and applied for the determination of
cyanide in industrial effluent and air. The method has been favourably
compared with ion selective electrode and other methods normally used
in steel industries and found to be sensitive and specfic.