Total cyanide determination by a segmented flow injection–on-line UV digestion–amperometric method

Abstract

Extensive species and concentration dependent cyanide recovery studies were carried out using a novel automated segmented flow injection–on-line UV digestion–amperometric (FI-UV) method for determination of total cyanide in water and wastewater samples. In addition, the response of the method to the presence of potential interferents was tested. The performance of the proposed method was compared with that of the standard method. The data obtained show that the FI-UV method has significant advantages over the EPA/ASTM approved procedures. Total cyanide levels and spike recoveries were determined for nine different industrial effluents. The precision and accuracy of the method, when applied to these effluents, expressed in terms of mean relative standard deviation and average percentage of spike recovery, were 1.5% and 101.0%, respectively. The technique developed eliminates the need for the time consuming, labor intensive distillation called for in the EPA/ASTM approved procedures. The method is rapid, selective and reproducible with a detection limit of 0.2 µg L^–1 and a throughput of 30 analyses per hour.