A rapid, sensitive, and specific screening technique for the determination of cyanide.

A colorimetric method for the screening of cyanide in biological specimens is presented. Cyanide in a 200-microL sample is diffused in a Conway 3 compartment dish into the center well where it catalyzes the reaction between p-nitrobenzaldehyde and o-dinitrobenzene. The resulting blue-violet color intensity is proportional to cyanide concentration. The reaction is specific for cyanide, and concentrations as low as 0.05 mg/L can readily be detected.