Silver Selective Electrode Based on Hybrid Mesoporous Silica (MCM-41) Modified Material

A silver selective electrode based on TEPQA-MCM-41 material was developed and used for the selective determination of Ag+ ion in various samples. The effect of various plasticizers i. e. dimethyl phthalate (DMP), Tris(ethylhexyl)phosphate (TEP), bis-(2-ethylhexyl)sebacate (BEHS), bis-(2-ethylhexyl)adipate (BEHA) was investigated. The electrode of the composition of 2 : 1 : 77 : 12 : 8 (w/w, %) of TEPQA-MCM-41 : NaTPB : Graphite powder : paraffin oil : DMP respectively, works satisfactorily in a wide concentration range of 1.3x10(-9) M-1.0x10(-1) M for Ag+ ion with a lower detection limit (LOD) of 1.0x10(-9) M and has Nernstian slope of 63.4 +/- 1 mV/decay. The electrode can be used in a pH range of 2.3 to 6.7 for a period of 3 months without any divergence in potential response. The selectivity coefficient calculated by fixed interference method indicates the high selectivity of the electrode towards Ag+ ion over other tested cations.