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Square Wave Voltammetric Determination of Lead(II) Ions Using a Carbon Paste Electrode Modified by a Thiol‐Functionalized Kaolinite
Author(s) -
Tonlé Ignas K.,
Letaief Sadok,
Ngameni Emmanuel,
Walcarius Alain,
Detellier Christian
Publication year - 2011
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.201000467
Subject(s) - kaolinite , carbon paste electrode , anodic stripping voltammetry , intercalation (chemistry) , electrode , detection limit , aqueous solution , analytical chemistry (journal) , square wave , inorganic chemistry , thiol , chemistry , carbon fibers , voltammetry , materials science , electrochemistry , cyclic voltammetry , mineralogy , composite number , organic chemistry , chromatography , composite material , physics , voltage , quantum mechanics
Abstract This work reports the electroanalysis of lead(II) in aqueous medium, using a carbon paste electrode modified by a novel thiol‐functionalized clay. This later was obtained upon the grafting of 3‐chloropropyltriethoxysilane onto the interlayer surfaces of kaolinite, followed by the substitution under carefully controlled conditions of chloro by thiol groups. The raw kaolinite, its dimethylsulfoxide (DMSO) intercalate used as starting material and the resulting hybrids were characterized by X‐ray diffraction, thermal analysis, infrared spectroscopy and CHNS elemental analysis. These techniques demonstrated the displacement of DMSO by the organosilane molecules which were grafted on the internal hydroxyl groups located on the kaolinite surface. The final functionalized kaolinite, with approximate chemical formula Si 4 Al 4 O 10 (OH) 6 [O 2 Si(OEt)(CH 2 ) 3 SH] was evaluated as electrode modifier for lead(II) sensing. A two‐step analytical procedure based on the accumulation at open circuit–detection was applied by square wave voltammetry. Various parameters affecting both the two steps were optimized: a linear response to lead(II) was obtained in the concentration range from 3×10 −7 to 10 −5 M, with a detection limit estimated at 6×10 −8 M. The interfering effect of some ions likely to influence the stripping determination of lead(II) ions was evaluated, and the proposed method applied to a real sample.