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Simultaneous determination of lead, copper, and mercury at a modified carbon paste eletrode containing humic acid
Author(s) -
Jeong EuhDuck,
Won MiSook,
Shim YeonBo
Publication year - 1994
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.1140061014
Subject(s) - chemistry , detection limit , copper , metal ions in aqueous solution , anodic stripping voltammetry , electrode , differential pulse voltammetry , inorganic chemistry , aqueous solution , analytical chemistry (journal) , mercury (programming language) , graphite , ion , electrochemistry , cyclic voltammetry , chromatography , organic chemistry , computer science , programming language
The modified carbon paste electrode (CPE) responding simultaneously to lead(II), copper(II), and mercury(II) ions has been constructed by incorporating humic acid (HA) into the graphite powder with Nujol oil. Simple immerging of the electrode into the measuring solution containing these metal ions led to the chemical deposition of the ions onto the electrode through the complexation of the ions with HA. Cyclic and differential pulse voltammetry (DPV) characterized the modified electrode's surfaces. Several cyclings of the potential regenerated the electrode (from more positive than the stripping potential of reduced Hg to more negative than the reduction of Pb(II)ion), which was then used for another deposition. After five deposition/measurement/regeneration cycles, the peak current of voltammograns of the analyte decreased slightly. The response reproduced with a 5.1% relative standard deviation. We also applied ihe differential pulse technique to the previously mentioned system. Here, the detection limit tor Pb(II), Cu(II), and Hg(II) ions were 5.0 × 10 −9 M 8.0 × 10 −9 M, and 8.0 × 10 −9 M, respectively, for 20 minutes of deposition time. After pretreatment of silver(I) ion with KC1, we could not observe any interference by other metal ions on the determination of the test ions in aqueous solution. Satisfactory results were acquired for the determination of the test metal ions in certified standard urine reference material SRM's 2670 (trace elements in urine).