Influence of Alkyl Chain on a Neutral-Carrier for Use in Selective Membranes Mercury Ions

摘要

Regarding the ISEs, their recognition element or ionophore is the main parameter to be considered at their building time, which is the reason to synthesize four molecules of the same family, all of them candidates to be the best recognition element for building a novel Hg(Ⅱ) ions selective electrode with a solid inner contact. The difference between the four structures is the alkyl group bound to one of the sulphur donating groups, the aliphatic chain can be: methyl, ethyl, propyl or butyl. Electrodes were prepared for each of the ionophores synthesized using the composition (%) of the ionophore membrane: o-NPOE:PVC:NaTPB with 5:62:33:1.0mg. The best neutral-carrier for the selective determination of mercury ions proves to be the ionophore containing the methyl in its structure, as its detection limit of (9.1 ± 0.8)×10~(-10) mol L~(-1), linear range (1.0×10~(-9) a 1.0×10~(1)) mol L~(-1) and Nernstian response (29.8 ± 0.4) mV decade~(-1) demonstrated.