Kinetic fluorimetric determination of cyanide by means of its catalytic effect on the aerial oxidation of pyridoxal-5-phosphate oxalyldihydrazone.
A highly specific determination of traces of cyanide is described, based on the catalytic effect of cyanide on the oxidation of pyridoxal-5-phosphate oxalyldihydrazone by dissolved oxygen. The reaction is monitored by measuring the fluorescence of the oxidation product (lambda(ex) 350, lambda(em) 420 nm), and allows determination of 3-180 ng ml cyanide concentrations with relative standard deviations of 0.4-0.8%. The effect of 56 foreign ions has been investigated: 45 of them do not interfere, and only one, Hg(II), interferes when present at the same level as the cyanide. Its application to the determination of total cyanide in industrial and synthetic samples, without preliminary distillation, is reported.
Rubio
S
S
Department of Analytical Chemistry, Faculty of Sciences, University of Córdoba, Córdoba, Spain.
Gomez-Hens
A
A
Valcarcel
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M