Abstract:

A comprehensive analytical method was developed for simultaneous determination of 28 corticosteroids in surface water based on ultra-high performance liquid chromatography- electrospray tandem mass spectrometry (UHPLC-ESI-MS/MS). The solid-phase extraction was performed using hydrophilic-lipophilic balance (HLB) cartridges, and the chromatographic separation was achieved on a reversed-phase C8 column. Qualitative and quantitative analyses were performed in the dynamic multiple reaction monitoring (DMRM) mode using positive and negative electrospray ionization (ESI±). The 28 target compounds were quantified by the internal standard method. Good linear relationships were obtained (R²>0.99) for the 28 analytes in the concentration range of 1.0-100 μg/L. The method limits of detection and quantification were in the range of 0.21-0.48 ng/L and 0.32-0.72 ng/L, respectively. When the matrix spiking levels were at 5.0, 10, and 50 ng/L, the average recoveries for the target compounds ranged from 68.6% to 108.7%, and the relative standard deviations (RSDs) were between 0.1% and 8.1%. Because of its high sensitivity, good precision, and reliability, this method can be widely applied to trace monitoring of glucocorticoids and mineral ocorticoids for investigating their behaviors and risks of corticosteroids in the environment.

Key words: corticosteroids, surface water, ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS)