Determination of cyanide as tetracyanonickelate(II) by flow injection and spectrophotometric detection

A two channel gas diffusion flow injection (GDFI) system was utilized successfully for the quantitative determination of cyanide. The analytical procedure is based on the complexation reaction in the acceptor stream between nickel ions in ammoniacal solution and the cyanide ions formed as a result of the diffusion of hydrogen cyanide from the acidified donor stream where the sample is injected. The design and the chemical parameters of the GDFI system were optimized with respect to sensitivity and sampling rate. The interference effect of a number of frequently encountered chemical species on the analytical determination was investigated in real samples and methods for their removal were developed. When applied to real samples where the cyanide ions are predominantly complexed with various metal ions the GDFI method was found to give results close to those obtained by standard distillation methods for weak acid dissociable (WAD) cyanide.