On-line determination of cyanide in the presence of sulfide by flow injection with pervaporation

Abstract

A pervaporation-flow injection (PFI) method is described for the analysis of cyanide in the presence of sulfide. The interfering sulfide ion in the injected sample is precipitated on-line using an acidified lead nitrate reagent solution before the donor stream enters the pervaporation cell. Using amperometric detection at a silver electrode set at -50mV (vs Ag/AgCl), linear calibration was obtained in the range 0.02-100.0 mg l-1 with a detection limit of 1.0 μg l-1. Sample throughput was of the order of 12-15 h-1. When the method was applied to the analysis of synthetic samples, there was no significant interference from sulfide at concentrations up to 50mg l-1. Thiocyanate did not interfere..