Determination of low concentrations of the flotation reagent ethyl xanthate by sampled DC polarography and flow injection with amperometric detection

A polarographic DCinst method with the static mercury drop electrode, SMDE, was developed for determination of the flotation collector ethyl xanthate (EtX) in the concentration range from 1x10(-5) to 8 x 10(-5) M. The potenti ality of the method was demonstrated by evaluating the capacity of powdered galena ore (PbS) to adsorb EtX in a titration-like procedure. Sulfide coul d be determined simultaneously with EtX because in NaOH electrolyte their a nodic waves are well separated (E-1/2 congruent to - 0.72 and - 0.42 V Vers us Ag/AgCl, respectively). In addition, a new FIA method was developed by a dapting a simple device to the tip of the glass capillary of a mercury elec trode and doing amperometric detection at a fixed potential of - 0.1 V, alw ays in the DCtast mode. No oxygen removal was required. Reproducible result s were obtained at a frequency of 72 injections per h, with automatic renew al of the SMDE every second. The calibration curve for freshly prepared EtX standards rendered a straight line from 5 x 10(-6) to 8 x 10(-5) hi with c orrelation coefficient of 0.997, suitable for real applications in flotatio n processes and its effluents. (C) 2001 Elsevier Science B.V. All rights re served.