Determination of trace borohydride in basic solutions using differential pulse polarography

Authors : Ülkü ÜNAL and Güler SOMER

Pages : 657-665

Doi:10.3906/sag-1202-96

View : 14 | Download : 8

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :Synthesis of borohydride is important because of its use as a hydrogen energy source. The objective of this study was to develop a new and simple method for the trace determination of borohydride so that it can be used during the investigation of a new reaction for its synthesis or in some kinetic studies. A differential pulse polarographic method has been developed for this purpose since the results obtained with this method are very reproducible and the instrument used is not expensive. The optimum working condition was found to be as 0.05 M phosphate buffer insert ignore into journalissuearticles values(pH 9);, containing 0.1 M KNO3 electrolyte. It allows trace determination of borohydride in the range of 10-4-10-6 M using the oxidation peak at --0.06 V with high accuracy. The detection limit was 6 \times 10-7 M in phosphate buffer. The nature of the peak was evaluated using direct current polarography and it was found that this peak at --0.06 V was an oxidation peak. There was no serious interference from some cations such as Crinsert ignore into journalissuearticles values(III);, Crinsert ignore into journalissuearticles values(VI);, Feinsert ignore into journalissuearticles values(III);, Cdinsert ignore into journalissuearticles values(II);, Pbinsert ignore into journalissuearticles values(II);, Zninsert ignore into journalissuearticles values(II);, Niinsert ignore into journalissuearticles values(II);, and Seinsert ignore into journalissuearticles values(IV); and anions such as chloride, bromide, nitrate, and sulfite when 2-14 times of borohydride was present. It was found that only copper insert ignore into journalissuearticles values(II); had an overlapping peak. This interference of copper was eliminated by the addition of EDTA. Using this procedure, in the presence of 5 \times 10-5 M copper, for 2 \times 10-5 M borohydride the result found was insert ignore into journalissuearticles values(1.9 \pm 0.2);10-5 M for N = 3 and 90% confidence interval.
Keywords : Trace borohydride, etermination, ifferential pulse polarography, opper interference