Electrochemically prepared chalcogenide ion-selective membranes as an alternative to conventional pressed-pellet ion-selective electrodes

✍ Scribed by M.T. Neshkova

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 920 KB
• Volume: 273
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/0003-2670(93)80165-h

✦ Synopsis

Applymg cathodic electrodeposltion of thm metal chalcogemde (selemde, tellunde or arsenide) membranes on an inert electroconductrve substrate, all-solid-state ion-selectwe electrodes (ISEs) were developed for Cu(II), Pb(II), A&) and cyanide Technologically, the eledrochermcal approach offers a cost-effective means of m situ membrane preparation which suits best the demand for disposable sensors for environmental and process control Membranes of very sophisticated composition and strongly defective structure were developed as a result of prehmmary membrane composition optimization studies A brief outhne of the optnnum electrodeposition conditions for each membrane 1s given The major advantage of these sensors as flow-mjection potentiometnc detectors was demonstrated on the examples of C+_,Se and Ag,,Se,,Te,,, membranes A linear Nemstian response was observed down to n x 10e6 M Cu(I1) or Ag(I) (n = 2-5) Interference of chlonde with Cu ISEs can be ehmmated with electroplated membranes m the flow-uqection mode for Cl concentrations up to 0 5 M, the lower hneanty hmrt still being 5 x 10m6 M Cu(II) It 1s shown that by switchmg from the steady-state to the flow-mJection mode, separation by rate of the Cu(II) potential-determmmg processes occurrmg at the membrane/solution interface m the presence of Clbecomes possible The potential of the electrochermcal approach for model response mechanism studies was demonstrated by the example of a Cu ISE The chenucal and phase composition of the Cuz_,Se membrane was vaned m the range 0 67 > x > 0 and the Cu(II) electrode function was examined for dtierent x values Conclusions with regard to the potential-generating reaction and the optimum membrane composition were drawn on tins basis