CYANIDE DETERMINATION IN BIOLOGICAL-FLUIDS USING A MICRODIFFUSION METHOD WITH A FLOW SYSTEM AND POLAROGRAPHIC DETECTION

The report describes a method for the automated polarographic determin ation of cyanide as tetracyanonickelate(II) anion complex in a gas-dif fusion flow system. The volatile cyanide, existing in whole blood, pla sma and urine samples, was measured after gas-diffusion using 8 x 10(- 5) mol l(-1) hexaaminenickel solution as acceptor. The linear range of calibration, for measurements at the hanging mercury-drop electrode ( HMDE), was from 0.1 to 2.0 mu g cyanide with r = 0.998, The RSD was, r espectively, 3.4 and 1.2% (n = 5) for 0.4 mu g cyanide measured with a nd without the flow-system configuration, Detection limits of 7.4 mu g l(-1) were calculated using the flow system and the method was compar ed with the classical method using Cavet flasks. Parameters that affec t the cyanide determination in the proposed method, such as acceptor s olution, pH, flow rate and temperature, were investigated.