Continuous flow and flow injection stripping voltammetric determination of silver( I ), mercury( II ), and bismuth( III ) at a bulk modified graphite tube electrode

The epoxy‐impregnated graphite tube electrode bulk modified with 2‐mercaptobenzoxazole, employed in a wall‐jet configuration, was found to be useful for the continuous flow and flow injection stripping voltammetric determinations of Ag I , Hg II and Bi III . For continuous flow, detection limits for Ag I , Hg II and Bi III were 1.8 × 10 −10 M, 1.9 × 10 −9 M and 9.5 × 10 −9 M, respectively (10 min accumulation, S / N = 3). Precisions for 5.00 × 10 −9 M Ag I , 1.00 × 10 −8 M Hg II and 1.00 × 10 −7 M Bi III were 10.5%, 5.77 % and 7.90% (relative standard deviations, n = 6), respectively. In the case of flow injection stripping, with a 500 μL injection loop, detection limits of 0.59 ng, 2.0 ng and 120 ng were obtained for Ag I , Hg II and Bi III , respectively ( S / N = 3). Selected metal ions, inorganic and organic substances were investigated for interferences. The electrode was tested with a certified sample and then applied to the determinations of the metal ions in a urine and a sea‐water sample.