A combined experimental/computational study on metal-organic framework MIL-101(Cr) as a SPE sorbent for the determination of sulphonamides in environmental water samples coupling with UPLC-MS/MS

As a novel kind of materials, metal-organic frameworks (MOFs) have great potential for the preconcentration of trace analytes. In our work, MIL-101(Cr) was prepared and applied as a solid phase extraction (SPE) sorbent for the pretreatment of sulfadiazine (SDA), sulfamethazine (SMZ), sulfachloropyridazine (SCP) and sulfamethoxazole (SMX) in different environmental water samples coupling with ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) detection. Experimental parameters, such as SPE materials, pH of water sample, volume of sample, flow rate, and type and volume of elution solvent, were properly optimized. Under the optimum conditions, good sensitivity levels were achieved with the detection limits of 0.03-0.08 μg/L and the quantitation limits of 0.11-0.27 μg/L. The linear ranges were from 0.2-40 or 0.5-100 μg/L (r2>0.996) for the analytes, and the relative recoveries were in the range from 83.5% to 107.3% with the relative standard deviations (RSD) between 0.2% and 8.0% (n=6). In addition, computational simulation was primarily used to predict the adsorption of MIL-101(Cr) toward sulphonamides (SAs), and also demonstrated the molecular interactions and free binding energies with the molecular modeling method. The results revealed that the combination of experimental and computational study not only accurately recognized the adsorption of MIL-101(Cr) on SAs, but also provided a new strategy on the trace contaminant analysis.