A dispersive liquid-liquid microextraction based on ionic liquids followed by HPLC-FLD for simultaneous determination of atenolol, metoprolol and propranolol in biological real samples and method optimization by taguchi experimental design.

A new dispersive liquid–liquid microextraction (DLLME) method based on ionic liquids followed by high-performance liquid chromatography-fluorescence detector (HPLC-FLD) has been developed for preparation and determination of atenolol, metoprolol and propranolol in urine real samples. Four effective parameters in DLLME process, including pH of aqueous sample, volume of dispersion and extraction solvents and ionic strength of donor phase, were optimized using fractional factorial screening methodology (FFSM) based on Taguchi experimental design [1]. The urine real samples were purified with sedimentation of Acyl glucuronic acid derivatives using 2 mol.L-1 NaOH solution. For DLLME, a mixture of ionic liquid (1-butyl-3-methyl imidazolium hexa fluoro phosphate) and disperser solvent (acetonitrile) was rapidly injected into the sample solution by syringe and semi cloudy solution is formed. Subsequently, the sedimented ionic liquid drop was analyzed by HPLC-FLD. The detection limits for all medicines were 0.08-1.2 ng.mL-1. The relative standard deviations (RSD) for ten experiments were between 4.02-4.81% for three target analytes. The proposed method illustrated wide dynamic linear range, desirable linearity, high enrichment factors and good extraction recovery. A comparison of this method with previous methods indicated that the suggested method is a reproducible, rapid and reliable sample pretreatment method that gives very good enrichment factors and detection limits for extraction and determination of pharmaceuticals in urine real samples.