Green application of surfactant modified silica as effective sorbent for extraction and preconcentration of sulfonamide residues in environmental water and honey samples.

Micro-solid phase extraction (µ-SPE) using surfactant coated silica for extraction and preconcentration of sulfonamide residues at trace levels in environmental water and honey samples prior their analysis by high performance liquid chronatography coupled with photodiode array detector (HPLC-PDA). The sample solution were dispersed in a small amounts of solid sorbent by vacuum manifold for sample preparation, and extraction occurred by adsorption in a short time. Finally, the analytes were subsequently desorbed using an appropriate solvent. The pure and coated silica were physicochemically and morphologically characterized by nittrogen (N2) sorptions analyses, and transmission electron microscopy (TEM). Parameters influencing extraction efficiency, such as amount of sorbent, kind, concentration and volume of surfactant, and kind and volume of desorption solvent, were investigated. The optimum conditions of the proposed method, were mixed standard/sample solution (10 mL), 0.4 g silica, 0.03 M CTAB (150 µL), and 500 μL methanol (as elution solvent). The proposed method, under optimal conditions, showed excellent linearity in different ranges (9-300 μg L-1, the a coefficient of determination (R2) of greater than 0.99), good repeatability (RSD < 6.72 %), good sensitivity (LODs in the range of 1 to 3 µg L-1), high enrichment factor (5.63-13.33), and acceptable relative recoveries (61.0-121.4 %). The developed µ-SPE method was applied to analyze sulfonamide residues in water and honey samples with relative recoveries of 60.9-119.4 % were obtained. This alternative method is simple and is also environmentally friendly which assessed using Analytical Eco-scale and Analytical GREEnness metric (AGREE).