抄録
A flow injection method for determining cyanide was applied to the screening of waste water samples from metal plating processes. A sample flowing at 1.2 ml/min was mixed with a sulfuric acid solution stream [2% (v/v), 0.4 ml/min] to adjust its pH to below 2. The acidified solution (200 μl) was introduced into a carrier stream [10% (w/v) NaCl, 2.0 ml/min] via an injector valve. Hydrogen cyanide liberated was diffused into a collector stream (0.1 N NaOH, 1.2 ml/min) through a Teflon membrane in a gas diffusion cell at 40°C. The collector solution was monitored with a flow-through cyanide ion selective electrode. The apparent permeability of cyanide was calculated as 34% at the 1 μg/ml level. A linear relationship was observed between the peak height and logarithmic concentration of cyanide in the range of 0.3-100μg/ml. The values determined by the present method (x) were in fair agreement with those obtained by the official method (y) for cyanide liberated at pH5. The following correlation was obtained between the two methods ; y=0.957 x+0.013 (r=0.946, n=50). By this method, 40 samples can be analyzed in one hour.
