Separation of Fluoroquinolones by MEKC Modified with Hydrophobic Ionic Liquid as a Modifier

Abstract

The hydrophobic ionic liquid [BMIM]PF 6 (1-butyl-3-methylimidazolium hexafluorophosphate) can interact with sodium dodecyl sulfate (SDS) micelles in aqueous solution and modify their physicochemical properties to produce a unique separation efficiency in micellar electrokinetic chromatography (MEKC). An MEKC method was developed using [BMIM]PF 6 as a modifier for separating eight fluoroquinolone compounds (ciprofloxacin, enrofloxacin, gatifloxacin, ofloxacin, norfloxacin, enoxacin, pazufloxacin, and tosufloxacin). The effects of several parameters on the separation selectivity, e.g., pH, concentration of background electrolyte, concentration ratio and amount of [BMIM]PF 6 and SDS, were investigated. Under the optimal conditions of 10 mmol L -1 sodium borate, pH 7.1, 1.7% (w/w) SDS, 1.5% (w/w) [BMIM]PF 6 with 18 kV as running voltage, the eight investigated quinolone compounds were baseline separated within 15 min. The selectivity of the developed method differed from that of the simple SDS micelles system containing no ionic liquid. The results suggest that hydrophobic ionic liquids should be promising modifiers in capillary electrophoresis, especially in MEKC analysis.

Effect of ionic liquids on the interaction between liposomes and common wastewater pollutants investigated by capillary electrophoresis

“…These experiments were performed by adding ILs to the BGE solution containing liposomes. Imidazolium ILs and other nitrogen-based ILs, linear and cylic, have previously been successfully used as BGE additives in the separation of various compounds [24,[34][35][36][37][38][39][40][41] and as surfactant modifiers [42][43][44] in EKC. Phosphonium ILs have not been as widely employed as pseudostationary phases in EKC, however, our group has successfully separated neutral compounds [23], aromatic compounds, and steroids [20] by using long alkyl chained phosphonium ILs.…”

Determination of fluoroquinolone antibiotics by microchip capillary electrophoresis along with time-resolved sensitized luminescence of their terbium(III) complexes

“…This method allows the separation of selected FQs as models (CIP, ENR and FLU) in less than 4 min, which is lower than the time required in other previously described methods using conventional CE [32][33][34][35][36][37]. The applied voltage (2 kV) was less than those applied in other CE systems.…”

Recent advances in CE analysis of antibiotics and its use as chiral selectors

“…EKC‐UV has also been applied to the separation of fluoroquinolone antibiotics . The separation of three fluoroquinolones (ciprofloxacin, norfloxacin, and ofloxacin) was carried out by MEKC with SDS in the BGE .…”

“…Separation was performed in approximately 8.5 min with LODs lower than 2.49 mg/L. Chen et al employed the ionic liquid 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([BMIM]PF 6 ) in combination with SDS in a 10 mM sodium borate buffer (pH 7.1) for the simultaneous separation of enoxacin, tosufloxacin, ofloxacin, norfloxacin, gatifloxacin, pazufloxacin, enrofloxacin, and ciprofloxacin . The effect of several parameters on the separation selectivity such as pH, concentration of BGE, concentration of ionic liquid, and surfactant, etc., allowed fixing the best experimental conditions for achieving the complete resolution.…”

“…1: Ofloxacin, 2: Norfloxacin, 3: Gatifloxacin, 4: Ciprofloxacin, 5: Enoxacin, 6: Pazufloxacin, 7: Tosufloxacin, 8: Enrofloxacin. Reprinted with permission from .…”