Assessment of constant current anodic stripping potentiometry for determination of arsenic in fish and water samples

An assessment of constant current anodic stripping potentiometry on a glassy carbon gold film electrode (GCAuFE) is described for the determination of arsenic in fish and water samples. The electrolytic preconcentration of arsenic, as As⁰, on the gold film was affected by the tendency for increased hydrogen evolution at longer deposition times (>3 min.), as well as by the presence of organic and inorganic substances. The hydrogen evolution problem was avoided by use of short deposition time (<1 min.), while organic end inorganic interferences were overcome either by sample decomposition and/or by use of standard additions for quantification. The decomposition of sample material by dry ashing with magnesium nitrate, as an ashing aid, enabled accurate determination of arsenic in fish on the GCAuFE. Reliable determination of arsenic in water samples was also accomplished after dilution with concentrated hydrochloric acid.