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Determination of iodide in samples with complex matrices by hyphenation of capillary isotachophoresis and zone electrophoresis
Author(s) -
Pantůčková Pavla,
Urbánek Marek,
Křivánková Ludmila
Publication year - 2007
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200700189
Subject(s) - isotachophoresis , capillary electrophoresis , chemistry , chromatography , iodide , seawater , electrolyte , capillary action , thermal conductivity detector , electrophoresis , analytical chemistry (journal) , chloride , gas chromatography , materials science , inorganic chemistry , composite material , geology , organic chemistry , oceanography , electrode
A method has been developed for the determination of iodide in mineral water, seawater, cooking salt, serum, and urine based on hyphenation of capillary ITP and zone electrophoresis. A commercially available instrumentation for capillary ITP with column‐switching system was used. ITP served for removal of chloride present in the analyzed samples in a ratio of 10 6 –10 7 :1 to iodide, zone electrophoresis was used for evaluation. Isotachophoretic separation proceeded in a capillary made of fluorinated ethylene–propylene copolymer of 0.8 mm id and 90 mm total length to the bifurcation point filled with a leading electrolyte (LE) composed of 8 mM HCl + 16 mM β‐alanine (β‐Ala) + 10% PVP + 2.86 mM N 2 H 4 ×2HCl, pH 3.2; and a terminating electrolyte composed of 8 mM H 3 PO 4 + 16 mM β‐Ala + 10% PVP + 5 mM N 2 H 4 , pH 3.85 for all the matrices except seawater. For ITP of seawater the LE consisted of 50 mM HCl + 100 mM β‐Ala + 10% PVP + 2.86 mM N 2 H 4 ×2HCl, pH 3.52. Distance of conductivity detector from the injection point and bifurcation point was 52 and 38 mm, respectively. Zone electrophoresis was performed in a capillary made of fused silica of 0.3 mm id and 160 mm total length filled with LE from isotachophoretic step. LODs reached for all matrices were 2–3×10 −8 M concentration (2.5–4 μg/L) enabled monitoring of iodide in all analyzed samples with RSD 0.4–9.3%. Estimated concentrations of iodide in individual matrices were 10 −6 –10 −8 M.