Selenocystine modified screen-printed electrode as an alternative sensor for the voltammetric determination of metal ions.

A novel selenium based screen-printed electrode was developed based on the immobilization of selenocystine on aryl diazonium salt monolayers anchored to a carbon-nanofiber screen-printed electrode support (SeCyst-SPCNFE). SeCyst-SPCNFE was analytically compared to a screen-printed carbon nanofiber electrode modified with L-Cystine (Cyst-SPCNFE) for the determination of Pb(II) and Cd(II) by stripping voltammetric techniques. Their analytical performance suggests that SeCyst-SPCNFE could be a much better alternative for metal ion determination at trace levels than Cyst-SPCNFE. The proposed electrode was successfully applied for the simultaneous voltammetric determination of trace Pb(II) and Cd(II) in a wastewater reference material with a very high reproducibility (3.2%) and good trueness (2.6%).