A Porphyrin Based Potentiometric Sensor for Zn2+ Determination

Abstract

PVC based membranes of disodium salt of porphyrin 3,7,12,17-tetramethyl-8, 13-divinyl 2,18-porphine dipropionic acid (I) as ionophore with sodium tetra phenyl borate (NaTPB) as anion excluder and dibutyl phthalate (DBP), dioctyl phthalate (DOP), dibutyl butyl phosphonate (DBBP), tris(2-ethyl hexyl)phosphate (TEP), tri-n-butylphosphate (TBP) and 1-chloronaphthalene (CN) as plasticizing solvent mediators were prepared and constructed for determination of Zn(II). The PVC based membrane of (I) with DBBP as plasticizer and having anion excluder, NaTPB in the ratio PVC: I: NaTPB: DBBP (150: 10: 2: 200) gave the best results in terms of working concentration range (1.3×10-5 -1.0 ×10 -1 M) with a Nernstian slope (30.0 mV/decade of activity). The useful pH range of the sensor is 3.0 -7.4, beyond which a drift in potential was observed. The response time of the sensor is 10s and the lifetime was about 2 months during which it could be used without any measurable divergence. It had good stability and reproducibility. The membrane worked satisfactorily in non-aqueous medium up to 40% (v/v) non-aqueous content. M, respectively. The electrode has been used as an indicator electrode to determine the end point in the potentiometric titration of Zn 2+ with EDTA.

Zinc(II) PVC-based membrane sensor based on 5,6-benzo-4,7,13,16,21,24- hexaoxa-1,10-diazabicyclo[8,8,8]hexacos-5-ene

“…Table 4 compares the selectivity coefficients, detection limit, and dynamic linearity range of the proposed sensor with the best previously reported Zn(II) sensors. 3,4,[8][9][10][11][12] As seen, the proposed sensor not only, in term of selectivity, but also, in terms of detection limit and linearity range is superior than the reported Zn(II) sensors.…”

“…5,6-Benzo-4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo [8,8,8]hexacos-5-ene was purchased from Fluka and used as received. The nitrate and chloride salts of all cations used (all from Merck and Aldrich) were of the highest purity available and used without any further purification except for vacuum drying over P 2 O 5 .…”

“…11,[14][15][16][17][18] In this paper, we wish to introduce a highly zinc(II)-selective sensor based on 5,6-benzo-4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo [8,8,8]hexacos-5-ene (BHDE), as a novel neutral ionophore for monitoring of zinc in industrial samples. BHDE is a cryptand with six oxygen and two nitrogen donor atoms in its structure.…”

“…Mostrou, em toda faixa de concentração usada, um tempo de resposta relativamente curto (< 10s), e pode ser usado por, no mínimo, 10 semanas em um intervalo de pH de 2,8 -7,3. O sensor proposto foi usado com sucesso na determinação direta de íons zinco em águas de descarte de companhias de eletrodeposição de zinco industrial, e também como um eletrodo indicador na titulação com EDTA.The 5,6-benzo-4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo [8,8,8]hexacos-5-ene (BHDE) was used as an excellent ionophore in construction of a Zn(II) PVC-based membrane sensor. The best performance was obtained with a membrane composition of 30% poly(vinyl chloride), 64.5% nitrobenzen (NB), 2.5% BHDE and 3% sodium tetraphenylborate (NaTPB).…”

“…The 5,6-benzo-4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo [8,8,8]hexacos-5-ene (BHDE) was used as an excellent ionophore in construction of a Zn(II) PVC-based membrane sensor. The best performance was obtained with a membrane composition of 30% poly(vinyl chloride), 64.5% nitrobenzen (NB), 2.5% BHDE and 3% sodium tetraphenylborate (NaTPB).…”