Combination of large volume sample stacking and dynamic pH junction for on-line preconcentration of weak electrolytes by capillary electrophoresis in comparison with isotachophoretic techniques |
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Authors: | Horáková Jana Petr Jan Maier Vítezslav Znaleziona Joanna Stanová Andrea Marák Jozef Kaniansky Dusan Sevcík Juraj |
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Institution: | Department of Analytical Chemistry, Palacky University, Trída Svobody 8, Olomouc, Czech Republic. |
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Abstract: | An on-line preconcentration capillary electrophoresis (CE) technique, which combines a large volume sample stacking with a dynamic pH junction technique, is introduced in this paper. This dynamic pH junction with co-electroosmotic migration is formed between sodium borate pH 9.5 and sodium phosphate pH 2.5 with 150 mM sodium dodecylsulfate (SDS). A full capillary based injection allows determination of weak acidic compounds at ppb concentration levels (achieved LOD for benzoic acid was 11 nmol L(-1)). The proposed preconcentration method was compared with ITP/ITP (LOD 120 nmol L(-1)), ITP/CZE (LOD 740 nmol L(-1)) and a simple CZE method (LOD 23,330 nmol L(-1)). The analytical potential of this method was assessed with juice test samples. |
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