Determination of Umifenovir and Its Metabolites by High-Performance Liquid Chromatography with Combined Mass Spectrometric Detection

An approach to the highly sensitive and selective determination of the bromine-containing antiviral drug umifenovir (Arbidol) and its metabolites in natural and waste water, activated sludge, and bottom sediments by chromatography-mass spectrometry based on a combination of two techniques– inductively coupled plasma mass spectrometry (ICP MS) and electrospray ionization high-resolution mass spectrometry (ESI HRMS) is developed. Reversed-phase chromatographic separation and detection based on ESI HRMS provide the reliable detection and identification of analytes in complex matrices, while the use of ICP-MS with 79Br signal detection makes it possible to exclude matrix effects and use a single analytical standard for quantitative analysis. The use of solid-phase extraction and pressurized liquid extraction as sample preparation methods made it possible to achieve limits of detection at a level of 0.2 ng/L and 2 µg/kg for liquid and solid samples, respectively. The developed approach was successfully tested in the analysis of real samples. It is shown that the concentrations of analytes in urban wastewaters are in the range 4.4–260 ng/L. The highest concentration (up to 3.7 mg/kg) is characteristic of activated sludge, which acts as an effective sorbent for umifenovir and its transformation products.