Magnetic solid-phase extraction of angiotensin II receptor antagonists in human urine and plasma with a reversed-phase/cation-exchange mixed-mode sorbent

Biocompatible magnetic nanoparticles that featured divinylbenzene and sulfonate functionalities were used for the magnetic solid-phase extraction of five angiotensin II receptor antagonists from human urine and plasma samples based on a reversed-phase and cation-exchange mixed-mode mechanism. Under the optimized extraction conditions, coupled to high-performance liquid chromatography with fluorescence detection, this proposed method was found to be accurate and precise with relative standard deviations of less than 11.7%, and a good recovery of 80.1-119.5% for both samples. The linear ranges were 0.2-2000 and 0.2-2500 ng/mL along with correlation coefficients above 0.9923 and 0.9928 for urine and plasma samples, respectively. Limits of detection were 0.01-5.74 and 0.01-1.31 ng/mL, respectively. The proposed magnetic solid-phase extraction based on the magnetic nanoparticles functionalized with divinylbenzene and sulfonate was a reliable and convenient sample pretreatment method and had the potential for isolating and enriching the angiotensin II receptor antagonists in biological samples.