Effect of 3-methyl-1-cetylimidazolium chloride ionic liquid on the electrophoretic preconcentration of steroid hormones

Abstract

We studied the capabilities of different versions of the on-line preconcentration of steroid hormones (field-amplifying sample stacking, sweeping, sweeping in high-salt sample matrix) in micellar electrokinetic chromatography using an ionic liquid (IL) of 3-methyl-1-cetylimidazolium chloride (C₁₆MImCl) as a component of a background electrolyte. The optimal conditions for the preconcentration of hormones are found. The simultaneous addition of the above ionic liquid (0.5 mM) and sodium dodecyl sulfate (25 mM) to the background electrolyte ensures efficiency of up to ∼1 × 10⁶ theoretical plates and detection limits for hormones down to 25–100 ng/mL.