RAPID DISTILLATIONLESS FREE CYANIDE DETERMINATION BY A FLOW-INJECTIONLIGAND-EXCHANGE METHOD

In the first part of this research, extensive species-dependent cyanid e recoveries studies were performed using the approved standard method s available for determination of free cyanide. The data obtained show that serious problems are associated with both the CATC (cyanide amena ble to chlorination) and WAD (weak and dissociable cyanide) methods. I n the second part, a novel flow injection gas-diffusion method for the determination of free cyanide was developed. Complete cyanide recover ies even in the presence of a large excess of the free CN- ion were fo und for the following species: [Zn(CN)(4)](2-), [Cd(CN)(4)](2-), [Ni(C N)(4)](2-), [CU(CN)(4)](3-), [Ag(CN)(2)](-), [Hg(CN)(4)](2-), and Hg(C N)(2). No recoveries of CN- were obtained from the species that are co nsidered as non free cyanide producing ones, such as [Fe(CN)(6)](3-)/( 4-), [Co(CN)(6)](3-), and [Au(CN)(2)](-). The method developed is rapi d, selective, reproducible, and easy to automate.