A comparative study on fabrication of Mn2 + selective polymeric membrane electrode and coated graphite electrode

Poly(vinyl chloride)-based membranes of two ligands 2,4-bis(2-acetoxybenzylamino)-6-phenyl-1,3,5-triazine (L1) and N2,N4-di(cyanoethyl)-2,4-bis(2-acetoxybenzylamino)-6-phenyl-1,3,5-triazine (L2) were fabricated and explored as Mn2 + ion selective electrodes. The performance of the polymeric membranes electrodes of ionophores with different plasticizers (dibutylphthalate, benzoic acid, o-nitrophenyloctyl ether, 1-chloronapthalene and tri-n-butylphosphate) and anion excluders (sodium tetraphenylborate and potassium tetrakis p-(chloro phenyl)borate) was looked in to and the better results were obtained with the membrane having composition L2: NaTPB: DBP: PVC as 6: 3: 56: 35 (w/w; mg). The coated graphite electrode (CGE) with same composition was also fabricated and investigated as Mn2 + selective electrode. It was found that CGE showed better response characteristics than PME. The potentiometric response of CGE was independent of pH in the range 3.0–9.0 exhibiting the Nernstian slope 29.5 ± 0.3 mV decade− 1 of activity and working concentration range 4.1 × 10− 7–1.0 × 10− 1 mol L− 1 with a limit of detection 6.7 × 10− 8 mol L− 1. The electrode showed a fast response time of 12 s with a shelf life of 105 days. The proposed CGE could be successfully used for the determination of Mn2 + ions in different water, soil, vegetables and medicinal plants also used as an indicator electrode in potentiometric titration with EDTA.

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► Polymeric membrane electrode (PME) and coated graphite electrode (CGE) based on L1 and L2 were fabricated and compared.
► CGE could selectively sense Mn2 + among metal ions checked.
► CGE is used for the determination of Mn2 + in different environmental samples.