Fabrication of magnetic zinc adeninate metal–organic frameworks for the extraction of benzodiazepines from urine and wastewater

In this study, an alternative method for synthesizing magnetic cobalt adeninate metal–organic frameworks was developed, and the synthesized materials were examined for their potential application for separating and enriching benzodiazepines from complex samples. Benzodiazepines, widely used as hypnotics, muscle relaxants, sedatives, and anxiolytics, are a class of drugs that require accurate detection and monitoring. Results showed that Fe3O4 nanoparticles could be well anchored onto the external surface of cobalt adeninate metal–organic frameworks by using amino‐silane as a linkage. Their adsorption of benzodiazepines was mainly promoted by intermolecular hydrogen binding, π–π interactions and electrostatic attraction. Their potential application was evaluated by extraction of benzodiazepines in urine and wastewater samples prior to liquid chromatography with mass spectrometry. Under optimum conditions, the calibration curves were linear with a correlation coefficient of ≥0.9928 in the concentration range of 10–5000 ng/L for lorazepam and 5–5000 ng/L for estazolam, chlordiazepoxide, alprazolam, midazolam and triazolam. The limits of detection were in the range of 0.71–2.49 ng/L. The percent of extraction recoveries were 80.2–94.5% for urine and 84.1–94.4% for wastewater, respectively. Results suggested that magnetic cobalt adeninate metal–organic frameworks could potentially be a promising material for enriching benzodiazepines from urine and wastewater with high accuracy and precision.