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.
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.
Horáková
Jana
J
Department of Analytical Chemistry, Palacký University, Trída Svobody 8, Olomouc, Czech Republic.
Petr
Jan
J
Maier
Vítezslav
V
Znaleziona
Joanna
J
Stanová
Andrea
A
Marák
Jozef
J
Kaniansky
Dusan
D
Sevcík
Juraj
J
D019817:Benzoic Acid / Q000032:analysis / Q000302:isolation & purification*; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D004586:Electrophoresis / Q000379:methods; D019075:Electrophoresis, Capillary / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D013011:Sorbic Acid / Q000032:analysis / Q000302:isolation & purification*
D019817:Benzoic Acid; D013011:Sorbic Acid