Determination of metronidazole and clarithromycin in plasma samples using surfactant-modified amorphous carbon-based...

This work offers preparation of surfactant-modified amorphous carbon and its application in dispersive solid phase extraction of metronidazole and clarithromycin from plasma samples. The extraction procedure was combined with dispersive liquid-liquid microextraction for further preconcentration of the analytes for sensitive determination of the analytes followed by high performance liquid chromatography-diode array detector. In this work, first, the sorbent was added to the sample and the mixture vortexed to adsorb the analytes. Then, the obtained supernatant after centrifuging is discarded and the loaded analytes onto the sorbent surface were eluted with a water-miscible organic solvent. In the following, to further enrichment of the analytes the microextraction step was done. For this purpose, the eluate is taken, mixed with a water-immiscible organic solvent, and injected into deionized water. After centrifuging, an aliquat of the sedimented phase is taken and injected into the analytical instrument for the quantitative analysis. Under the optimum extraction conditions, high extraction recoveries (79 and 89% for metronidazole and clarithromycin, respectively), low limits of detection (2.1 and 1.9 ng mL^-1 for metronidazole and clarithromycin, respectively) and quantification (7.0 and 6.3 ng mL^-1 for metronidazole and clarithromycin, respectively), good repeatability (relative standard deviations less than 4.3% for intra- and 6.3% inter-day precisions), and wide linear ranges (7.3-1000 and 6.3-1000 ng mL^-1 for metronidazole and clarithromycin, respectively) were obtained. At the end, the introduced method was applied on the plasma samples of the patients treated with metronidazole and clarithromycin successfully.