Determination of salmeterol in dried blood spot using an ionic liquid based dispersive liquid-liquid microextraction coupled with HPLC

A novel analytical method based on the use of a modified dispersive liquid-liquid microextraction (DLLME) technique by ionic liquids has been developed for the first time. This method was applied for the determination of salmeterol in dried blood spot samples from asthmatic patients followed by HPLC system equipped with fluorescence detector. The main novelty of the present work deals with the analysis of salmeterol in dried blood spot with significant advantages with regard to invasive sampling, volume of blood used (<20 mu L), storage and transport of biological materials and requirements for special biohazard arrangements. The effects of significant factors in microextraction procedure including extracting and disperser solvents volume, sample pH and salt contents were investigated. Under optimized conditions, the mean recoveries were higher than 90.0% with linear responses about 1.00-500 ng mL(-1) concentration range. The limit of detection (LOD) was 030 ng mL(-1) in S/N of 3. Intra-day (n = 6) and inter-day (n = 3) assay precision showed relative standard deviation lower than 6.0 and 8.5% for studied drug, respectively. The developed microextraction procedure was simpler and faster than conventional extraction techniques and was omitted hazard organic solvents. Finally, the proposed method is suitable for the analysis of salmeterol in dried blood spots from asthmatic patients for therapeutic drug monitoring purpose. (C) 2013 Elsevier B.V. All rights reserved.