Μagnet integrated fabric phase sorptive extraction (MI-FPSE) for the selective isolation of seven sulfonamides from human urine prior to HPLC-DAD analysis

In the present study magnet integrated fabric phase sorptive extraction (MI-FPSE) was employed for the selective extraction of seven sulfonamides (i.e., sulfamerazine, sulfamethazine, sulfamethoxypyridazine, sulfamonomethoxine, sulfamethoxazole, sulfisoxazole and sulfadimethoxine) from human urine prior to their determination by high pressure liquid chromatography – diode array detection (HPLC-DAD). The MI-FPSE protocol was optimized after studying the critical parameters that affect extraction, namely: type of sol–gel sorbent, extraction time, desorption time, stirring rate, type and volume of elution solvent, the ionic strength and the pH of the sample matrix using the one-factor-at-a-time method. The developed MI-FPSE-HPLC-DAD method was validated in terms of linearity, sensitivity, selectivity, accuracy, and precision and presented satisfactory results. The limits of detection (LODs) and quantification (LOQs) ranged between 0.02–0.04 ng/μL and 0.06–0.15 ng/μL, respectively. The RSD% values of the intra-day and inter-day assays were found lower than 6.7 % and 9.4 %, respectively, showing good precision. Accuracy was assessed using percentage of relative recovery and varied from 86.3–112.9 % (intra-day study) and 85.5–106.9 % (inter-day study) for all examined analytes. The green character and practicality of the proposed method were investigated using the ComplexGAPI index and Blue Applicability Grade Index (BAGI).