Simultaneous extraction and preconcentration of three beta (ß)-blockers in biological samples with an efficient magnetic dispersive micro-solid phase extraction procedure employing in situ sorbent modification

A straightforward and sensitive magnetic dispersive micro-solid phase extraction based on in situ sorbent modification in sample solution was developed for the simultaneous extraction of metoprolol, atenolol, and propranolol (three beta-blockers) in human plasma and urine samples. To prepare a suitable sorbent, magnetic graphene oxide as a magnetic core was synthesized and modified with sodium dodecyl sulfate in the sample solution containing the analytes. In the procedure, the sorbent synthesis and the analyte extraction were simultaneously performed in the sample solution, which leads to a reduction in the time and cost of the determination of the analytes. Three surfactants such as cetyltrimethylammonium bromide, triton X100, and sodium dodecyl sulfate were utilized to modify the magnetic graphene oxide composites and their effects on the extraction of beta-blockers were investigated. The effective variables in the microextraction process of the analytes were optimized based on a design of experiment strategy. Under the optimal conditions, the dynamic ranges of linear were 5-10000, 50-5000, and 10-5000 ng mL(-1) with method detection limits of 0.8, 10, and 2 ng mL(-1) for Atenolol, Metoprolol, and Propranolol, respectively The relative standard deviations of the intra-day and inter-day were less than 2.96% and 5.35% (n = 5) for the determination of the analytes, respectively. A suitable enrichment factors of 14, 16, and 18 were obtained for the determination of metoprolol, atenolol, and propranolol, respectively. Finally, the suggested method was successfully applied to measure the beta-blockers in several plasma and urine samples of healthy volunteers without taking drugs and patient volunteers with taking drugs. The method shows suitable relative recoveries in the ranges of 82.4-109.4% and 77.6-95.9% for the analysis of urine and plasma samples with relative standard deviations between 3.1 and 6.7% for the determination of all analytes, respectively.