Development of a dispersive solid-phase extraction based on modified biopolymers combined with dispersive liquid-liquid microextraction for extraction of clarithromycin and metronidazole in biological samples and their determination by high performance liquid chromatography

Abstract

Introduction: In this method, a DSPE procedure in combination with DLLME has been used for the extraction and preconcentration of s metronidazole and clarithromycin from human plasma using surfactant modified amorphous carbon in the DSPE step. Expression of purpose: The main goal of this work was preparation of surfactant–modified amorphous carbon and its application in dispersive solid phase extraction of metronidazole and clarithromycin from plasma samples. Methods: First, 0.5 mL of blank plasma spiked with the analytes was diluted with HPLC–grade water at a ratio of 1:2(v/v). After dissolving, 2.5%, w/v NaCl, 15 mg of the prepared sorbent was added and the mixture was vortexed for 2 min. In the following, 0.5 mL methanol was used for desorption of the selected drugs from the sorbent. To obtain high enrichment factors, the eluate was mixed with chloroform at 50μL level and DLLME method is done. After centrifuging, the sedimented phase was evaporated to dryness under stream of nitrogen at room temperature. The residue containing the enriched analytes was reconstituted in 20 μL of the mobile phase and injected into the HPLC–DAD system. Results: ER was in the ranges 79-89%. LOQ and LOD were in the range of 6.3-7 ng mL-1 and 1.9-2.1 ng mL–1, respectively. RSDs for extraction of the selected antibiotics were (≤6.3%). Discussion and conclusion: In this work, for the first time, surfactant-modified amorphous carbon nanoparticles were prepared through a simple and rapid process and used as an efficient sorbent in DSPE procedure. The developed approach provided satisfactory outcomes such as low LODs and LOQs, high ERs, and wide LRs. Also, having no serious matrix effect allowed the method to be applied on patient’s plasma samples.