Petr Jan, Vítková Katerina, Ranc Václav, Znaleziona Joanna, Maier Vítezslav, Knob Radim, Sevcík Juraj
Department of Analytical Chemistry, Faculty of Science, Palacky University in Olomouc, Trida Svobody 8, Olomouc, Czech Republic.
J Agric Food Chem. 2008 Jun 11;56(11):3940-4. doi: 10.1021/jf8000179. Epub 2008 May 13.
An online accumulation/mobilization preconcentration technique based on a dynamic pH junction technique and electrokinetic injection was employed for analysis of phenolic acids (sinapic, ferulic, coumarinic, caffeic, syringic, vanillic, and 4-hydroxybenzoic acid) in extracts from Majorana hortensis leaves. Samples were extracted by pressurized solvent extraction with acetone at 150 degrees C and 15 MPa. The capillary electrophoretic method employed 50 mmol.L (-1) sodium borate, pH 9.5, as the sample electrolyte, 50 mmol.L (-1) sodium phosphate, pH 2.5, as the background electrolyte, and 50 mmol.L (-1) sodium phosphate, pH 2.5, with 60 mmol.L (-1) sodium dodecyl sulfate as the mobilization electrolyte. The method allowed 720-fold to 5560-fold preconcentration of the phenolic acids during 30 min of electrokinetic accumulation with detection limits from 0.38 to 4.22 ng.mL (-1).
