Magnetic metal-organic frameworks-101 functionalized with graphite-like carbon nitride for the efficient enrichment of glucocorticoids in cosmetics

In this work, magnetic metal-organic frameworks-101 functionalized with graphite-like carbon nitride material (Fe 3 O 4 /g-C 3 N 4 /MIL-101) has been simply prepared for the efficient enrichment of glucocorticoids in cosmetics. Due to the introduction of g-C 3 N 4 , the water stability of MIL-101 has been greatly improved. This composite material also showed better selectivity for glucocorticoids than those for polycyclic aromatic hydrocarbons and benzene compounds due to the hydrogen bonding effect with g-C 3 N 4 and the size-matching effect with MIL-101. When the prepared material was used as the sorbents in magnetic solid-phase extraction (MSPE) and coupled with ultra-performance liquid chromatography-mass spectrometry (UPLC-MS/MS), a sensitive MSPE-UPLC-MS/MS method was developed. Under the optimal conditions, the calibration curves were linear over the concentration ranging from 0.01 to 2 μg/L with correlation coefficients (R 2 ) between 0.9915 and 0.9995. The limit of detection (LOD) was as low as 2 ng/L with the RSDs lower than 5.5%. The recoveries ranged from 77.3% to 113%. The LOD of glucocorticoids in real samples analysis was improved by nearly three orders of magnitude compared to current literature records. The results indicated that Fe 3 O 4 /g-C 3 N 4 /MIL-101 could be used as MSPE extractant to determine glucocorticoids in complex cosmetics matrix.