New sample preparation techniques for the analysis of azole antifungal drugs in biological samples (#81)
Sample preparation miniaturization often results in increased analyte enrichment factor, faster speed, easier automation and solvent and sample savings. This work explores new approaches in microextraction utilizing mesoporous materials. Solid phase membrane tip extraction (SPMTE) incorporating mesoporous silica MCM-41 was developed and combined with high performance liquid chromatography (HPLC) for the determination of azole antifungal drugs, namely voriconazole (VRZ), ketoconazole (KTZ) and itraconazole (ITZ) in human plasma. It required minute amounts of sorbent (3 mg) and desorption solvent (100 μL). The developed method showed high recoveries in the range of 82.5-111.0%, acceptable precision (RSD < 16%, n = 3) and low limits of detection (LODs) (20-40 µg L-1). Dispersive micro-solid phase extraction (D-μ-SPE) coupled with liquid chromatography tandem mass spectrometry (LC-MS/MS) was used to successfully determine six azole antifungal drugs namely fluconazole (FLZ), VRZ, KTZ, econazole (ECZ), clotrimazole (CTZ) and miconazole (MCZ) in human plasma and urine. It provides excellent LODs (0.003-3.000 µg L-1), good precisions (RSDs < 16 n = 9) and good analyte recoveries (76.3-116.8%). Vinyl functionalized mesoporous carbon, V-COU-2 in dispersive solid phase extraction (V-COU-2-DSPE) was developed and LODs in the range of 0.4 - 0.5 µg L-1 were obtained for KTZ and ITZ, respectively, with good linearity in the range of 1 - 300 µg L-1. The method was successfully applied to the analysis of urine and human plasma samples to give high analytes recoveries (89.8 - 113.9%) and RSDs < 13%, (n = 3). The proposed techniques proved to be suitable alternative extraction techniques for efficient, simple and rapid sample clean-up and determination of azole drugs in biological samples.