Effect of urea addition in micellar electrokinetic chromatography

Parameters controlling the elution window and retention factors in micellar electrokinetic capillary chromatography

“…Moreover, the elution window will be extended by the addition of organic modifiers [10,11]. To study the influence of different organic modifiers in MECC, experiments were carried out with an electrolyte system of 0.01 M TRIS-boric acid at pH 8.5, containing different amounts of methanol, acetonitrile or urea.…”

“…In reversed-phase high-performance liquid chromatography it has been shown that the variation of the retention factor, k, with the volume fraction of organic solvent in the aqueous-organic mobile phase, ~b, is reasonably well described by [27]: Ink = A + Bth + C~) 2 (11) where A, B and C are constants for a specific solute and eluent combination. For a small range of solvent compositions Eqn.…”

“…Applying the same instrumentation as in capillary zone electrophoresis, in MECC uncharged compounds can be separated based on differences in their partitioning between two phases, just as in chromatographic techniques. Since the introduction of MECC by Terabe et al [1,2], several authors have paid attention to the fundamental characteristics of this separation method [3,4] and to the effect of different separation parameters on the migration behavior [5][6][7][8][9][10][11]. Also the theoret-the solute in the micellar and the aqueous phase, and ts, tEO F and tMC are the migration times of the solute, the electroosmotic flow (EOF) and the micelles, respectively.…”

Determination of Amino Acids in Tobacco Samples by Capillary Electrophoresis/Indirect Absorbance Detection with Isolation of the Electrolysis Compartment and p-Aminobenzoic Acid as a Background Electrolyte

“…Amino acids can be determined by an amino acid analyzer, 1 high-performance liquid chromatography (HPLC), 2 gas chromatography (GC) 3,4 and capillary electrophoresis (CE). 5,6 CE has been employed in the determination of amino acids because of its high separation efficiency, low sample consumption and fast analysis velocity. Since most amino acids have insufficient UV absorbance and no fluorescence, their spectrometric methods, such as UV-Vis absorbance, 5,6 fluorescence (FL) and laser-induced fluorescence (LIF), [7][8][9] are mainly based on pre-or post-column derivation.…”

“…5,6 CE has been employed in the determination of amino acids because of its high separation efficiency, low sample consumption and fast analysis velocity. Since most amino acids have insufficient UV absorbance and no fluorescence, their spectrometric methods, such as UV-Vis absorbance, 5,6 fluorescence (FL) and laser-induced fluorescence (LIF), [7][8][9] are mainly based on pre-or post-column derivation. The derived amino acids can improve the detection sensitivity, but the deriving operations are troublesome and time-consuming.…”