The role of high-resolution mass spectrometry in environmental research: Developments and challenges

The analysis of environmental samples involves dealing with high matrix complexity, low concentrations, and thousands of potential contaminants. Analytical investigation of organic contaminants based on high-resolution mass spectrometry (HRMS) hyphenated to chromatography can follow different strategies: target, suspect and non-target analysis. In target analysis, the main objective is reliable identification and quantification of a limited list of known contaminants for which reference standards are available. However, many potential contaminants present in the samples can remain ignored by this approach. This highlights the need for applying strategic workflows to face this challenge. To this aim, HRMS appears as the most powerful tool at present owing to the valuable information contained in the accurate-mass full-spectrum data. HRMS(/MS) screening approaches are feasible using large databases, where detected “suspects” can be tentatively identified employing this data. The complementary use of spectral libraries, prediction tools and in-silico methods show huge potential for the efficient and comprehensive screening of large number of organic contaminants. If a compound detected cannot be tentatively identified because it is not present in any library, a variety of non-target approaches exist for further identification. The first step is usually peak picking, either using commercial (vendor) software or one of the open-source approaches. In contrast to target analysis, suspect and non-target screening are less mature forms of data exploration and require more time and mass spectrometric fragmentation knowledge for a successful application. This seminar aims to discuss the pros and cons of the different HRMS acquisition workflows and data exploration approaches, but also pays attention to new developments such as ion mobility and the use of prediction tools to improve the identification capabilities in high-complex samples.

Dr. Lubertus Bijlsma is researcher at the Research Institute for Pesticides and Water (IUPA) of the University Jaume I (UJI), Castellon, Spain. His research interests focus on wastewater-based epidemiology and the use of liquid chromatography coupled to low-resolution and high-resolution mass spectrometry in environmental science. One of his most recent research activities in this field is directed towards the use of ion mobility separations coupled to HRMS. In 2021, he was awarded a prestigious Postdoctoral Junior Leader fellowship funded by “la Caixa” Foundation in the framework of a Marie-Curie Action to implement the project entitled “Wastewater-based epidemiology as surveillance and early warning of antimicrobial agents usage and resistance to the community level (SEWAR)”. He was additionally awarded a grant Ramón y Cajal that permits him to enter a tenure track at UJI. He currently is the vice-coordinator of the Sewage Analysis CORe group Europe (SCORE) network and member of the Editorial Board of Science of the Total Environment.