Ion-selective gold–thiol film on integrated screen-printed electrodes for analysis of Cu(ii) ions

Abstract

A novel type of ion-selective electrode (ISE) was manufactured for detecting trace amounts of Cu(II) ions. The basic substrates of ISE were fabricated using screen-printing technology, which could produce disposable electrodes on a large-scale with good repeatability. Moreover, the printed integrated three-electrode system of ISE could be directly used to read out the open-circuit potentials by a handheld device through a USB port. The ion-selective film was composed of gold nanorods (GNRs) and 6-(bis(pyridin-2-ylmethyl)amino)hexane-1-thiol (compound a), which were layer-by-layer modified on the electrode through an easily controlled self-assembly method. Compound a contained the 2,2′-dipyridylamine (dpa) group that could coordinate with Cu(II) ions to form a 2 : 1 complex, therefore the screen-printed ISEs exhibited Nernstian potentiometric responses to Cu(II) ions with a detection limit of 6.3 × 10⁻⁷ mol L⁻¹ over the range of 1.0 × 10⁻⁶ to 1.0 × 10⁻² mol L⁻¹. The easily prepared screen-printed ion-selective electrode reported here was appropriate for in field analysis and pollutant detection in remote environments.