Application of dc and mark-space bias differential electrolytic potentiometry for determination of cyanide using a programmable syringe pump

Abstract

This paper describes a rapid sequential injection titration method for the determination of cyanide in aqueous solutions. Mercuric nitrate was used as a titrant and a pair of gold-amalgam electrodes as an indicating system. The technique of differential electrolytic potentiometry using both mark-space bias (m. s. b.) and dc current for polarization was employed. The optimum values of current and percentage bias were 5 μA and 13%, respectively. The effects of dispense time, volume of analyte, supporting electrolyte, and the concentration of titrant were investigated. The results obtained are in agreement with those of the standard method (APHA), with a relative standard deviation of 1. 43%, t = 0. 783, F = 1. 713. A sampling rate of about 20 samples per hour was achieved with good reproducibility and lower consumption of reagents. © 2011 The Author(s).