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A cathodic stripping technique for the determination of trace levels of arsenic and selenium in waste, organic, and environmental samples

Technical Report ·
OSTI ID:6015595
This paper describes a sensitive, accurate method based on electrochemical cathodic stripping to determine trace levels of arsenic and selenium. Advantage of this technique is the ability to preconcentrate the elements at the mercury electrode as mercury complexes. These compounds can then be stripped back into the supporting electrolyte of HCl with the resulting current proportional to the concentration. A PARC model 384B polarographic analyzer with multiple 303A static drop mercury electrodes was used to analyze samples with detection limits of 0.005 mg/L for both arsenic and selenium. The primary obstacle to the use of high sensitivity voltammetric analysis has been high background currents caused by the presence of electroactive substances in the sample matrix. In order to eliminate this problem, sample preparations consist of a perchloric/nitric acid digestion for aqueous samples, or oxygen bomb digestion for organic samples. These techniques have proven satisfactory for most samples and result in a sample matrix that is satisfactory for voltammetric analysis. An anion/cation ion exchange technique has been developed to eliminate background problems. In addition, the ion exchange eliminates direct interference from metals such as copper, lead, and tin.
Research Organization:
Oak Ridge Gaseous Diffusion Plant, TN (USA)
DOE Contract Number:
AC05-84OT21400
OSTI ID:
6015595
Report Number(s):
K/PS-5078; ON: DE88002257
Country of Publication:
United States
Language:
English