A new differential pulse polarographic method for the determination of some ions in different media, application to real samples

It is known that trace elements found in cow liver such as Cu, Cd, Pb , Zn and Se exhibited interference with selenite during their DPP determination. This interference could be eliminated by working at pH=8.5 medium. These trace elements found in cow liver were determined using DPP in two media where interference with Se will occur and will not occur. It was found that the quantities for Cu, Cd, Pb and Zn were larger in medium where interference does not take place. The quantities of trace elements found in cow liver which have no interference with Se, such as Cr, Fe, Se, Mo and Ti were also determined at appropriate electrolyte conditions.It was found that the best medium for the direct and indirect determination of sufite using DPP was pH 4 HAc/ NaAc buffer. With the sulfite peak at about ?0.6 V in this medium it was possible to determine 2x10-6 M of sulfite by direct method. However, with indirect method using selenite as oxidizing agent, 7x10-7 M of sulfite could be determined.Nitrite ion could be determined both by direct and indirect methods. The best medium was found to be as pH 5 HAc/ NaAc buffer. In direct method the peak at about ?1.4 V was used and it was possible to determine 6x10-6 M nitrite. Sulfite ion was used as reducing agent for the indirect method and 2x10-6 M nitrite could be determined.The method for nitrite determination was successfully applied for sausage and the new method for sulfite determination was applied for apricot and wine.The interference between Cr(VI) and Se(IV) in pH 8.5 acetate electrolyte, could be eliminated by phosphate and borate. In the presence of either phosphate or borate, it was possible to determine 9x10-8 M Cr (VI) by using its peak at ?0.4V. The developed method was applied to Gerede river and chromium content of it was determined.