Stripping voltammetry microprobe (SPV): Substantial improvements of the protocol

•Stripping voltammetry microprobe (SPV) allows determining the concentration of an analyte in samples up to 10 μL.•The active specie is precipitated on an electrode surface, and analyzed by CV or DPV.•There are two restrictions for the analyte.•(i) Submit a redox couple in the potential window; (ii) be insoluble in the electrolyte.

The recently introduced new electroanalytical protocol of stripping voltammetry microprobe (SPV) has been considerably improved with respect to analytical performance. The determination of the silver ions is shown to be possible by the precipitation of a solution of silver drops on an electrode surface, which is previously moistened with a solution of NaCl. The electrode thus modified, i.e., with the silver chloride precipitate on the surface, is introduced into a chloride electrolyte and is negatively polarized to reduce the silver salt to metallic silver. Whereas this reduction process produces only a broad signal, the following electrochemical oxidation of the silver metal back to AgCl provides a highly sensitive and narrow signal, which lends itself for analysis. The linear range for determination of silver ions following this protocol is 1.4 × 10−7 to 7.4 × 10−4 mol L−1 and the detection limit is 4.6 × 10−8 mol L−1.

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