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A Study on Stripping Voltammetric Determination of Osmium(IV) at a Carbon Paste Electrode Modified In Situ with Cationic Surfactants
Author(s) -
Galík Michal,
Cholota Michal,
Švancara Ivan,
Bobrowski Andrzej,
Vytřas Karel
Publication year - 2006
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.200603650
Subject(s) - potentiometric titration , detection limit , osmium , chemistry , bromide , carbon paste electrode , stripping (fiber) , ammonium bromide , cationic polymerization , electrochemistry , inorganic chemistry , ammonium , cathodic stripping voltammetry , analyte , electrode , nuclear chemistry , voltammetry , cyclic voltammetry , chromatography , materials science , pulmonary surfactant , polymer chemistry , catalysis , organic chemistry , biochemistry , composite material , ruthenium
This article deals with the development of a method for the determination of osmium at a carbon paste electrode (CPE) modified with cationic surfactants of the quaternary ammonium salt type; namely, cetyltrimethylammonium bromide (CTAB) and 1‐(ethoxycarbonyl)‐pentadecyltrimethyl‐ammonium bromide (Septonex); both being added in situ and serving for preconcentration of osmium via its hexachloroosmate(IV) anion. The proper electrochemical detection was performed by cathodic scanning in the differential pulse voltammetric mode. Optimization studies concerning important experimental parameters also included a specially performed potentiometric titration, helping to define the actual stoichiometry for the ion‐pairing process, the main principle and driving force of the accumulation step. In a chloride/acetate buffer based supporting medium and with Septonex as the modifier of choice, the reduction signal for osmium was found to be proportional to the Os(IV) concentration in a range from 5×10 −9 to 5×10 −7 mol L −1 with a limit of detection close to 5×10 −9 mol L −1 (with preconcentration for 60 s). The method capable to determine Os(IV) in the presence of both Pt(IV) and Ir(III) was tested on model solutions as well as with real sample of industrial waste water (spiked with the analyte); both yielding the recovery rates within 88–99%.