Manufacture of Lead-Specific Screen-Printed Sensor Based on Lead Schiff Base Complex as Carrier and Multi-Walled Carbon Nanotubes for Detection of Pb(II) in Contaminated Water Tests

摘要

A novel screen-printed electrode (SPE) based on [Pb(L)] complex (H2L = 2-((2-(2-(2-(2-hydroxy-5- methoxybenzylidene amino)phenyl)disufanyl)phenylimino) methyl)-4-methoxyphenol) was preparedfor selective determination of Pb(II)ion. The ligand and its Pb(II) complex were prepared and1 characterized using elemental analysis, spectroscopic (IR and H NMR) and molar conductance.Different individual variables were optimized using IUPAC recommendation such as graphite powder,plasticizer, amounts of [Pb(L)] complex ionophore and multi-walled carbon nanotubes (MWCNT).Their possible interactions were investigated. In this potentiometric method, fabrication of screen- printed (SPE; electrode V) and multi-walled carbon nanotubes-screen-printed (MWCNT-SPE;electrode IX) sensors was described. [Pb(L)] complex alone or with MWCNT was used as modifier incase of electrodes V and IX, respectively. Optimum composition resulted in enhancement in thesensitivity and selectivity of the SPE toward Pb(II)ions significantly over the concentration range of-7 -1 -8 -1 -1 -7 1.0 10 -1.0 10 and 4.6 10 -1.0 10 mol L of Pb(II)with detection limit of 1.0 10 and 4.6-8 -1 -1 10 mol L and a Nernstian slope of 28.980.92 and 30.280.70 mV decade for electrodes V andIX, respectively. No significant change in response was observed over the pH range of 3.0-8.0 and 2.5- 8.5 with response time lower than 9 and 7s for electrodes V and IX, respectively. The potentiometricselectivity coefficients were calculated and the results obtained showed the good selectivity of themodified SPE electrodes (V and IX) for Pb(II) ion over other metal ions. Finally, these electrodes wereprecisely applied for the determination of Pb(II) ions in real spiked water samples. The results obtainedusing both the proposed potentiometric method and atomic absorption spectrometer (AAS) showedsatisfactory agreement.