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Differential pulse stripping voltammetric determination of thallium with an 8‐hydroxyquinoline‐modified carbon paste electrode
Author(s) -
Cai Qiantao,
Khoo Soo Beng
Publication year - 1995
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.1140070415
Subject(s) - thallium , detection limit , chemistry , masking agent , stripping (fiber) , differential pulse voltammetry , carbon paste electrode , electrode , anodic stripping voltammetry , metal , analytical chemistry (journal) , voltammetry , 8 hydroxyquinoline , nuclear chemistry , inorganic chemistry , electrochemistry , cyclic voltammetry , materials science , chromatography , organic chemistry , composite material
A carbon paste electrode incorporating 8‐hydroxyquinoline was fabricated to selectively accumulate Tl I at open circuit. The accumulated Tl I , after reduction to metallic thallium at the electrode surface, was anodically stripped by differential pulse voltammetry. Under optimized conditions, Tl I concentrations in the range 1.00 × 10 −8 M − 1.00 × 10 −5 M gave two linear regions due to different controlling factors for accumulation. A detection limit of 4.90 × 10 −9 M (1.00 ppb) was found for a 120‐s accumulation. For 10 determinations of Tl I at concentrations of 1.00 × 10 −6 M and 1.00 × l0 −7 M, relative standard deviations of 2.60% and 3.20% were obtained, respectively. Interferences from Bi III , Pb II and Cu II could be removed by masking with complexing agents such as sodium diethyldithiocarbamate, EDTA, sodium citrate, etc. A method was developed for thallium speciation and analysis, based on the determination of Tl I while masking Tl III with EDTA followed by chemical reduction of Tl III to Tl I with hydroxylamine hydrochloride. This method was tested using a synthetic sample containing known concentrations of Tl I and Tl III .