High-Resolution Mass Spectrometry Imaging in Environmental Research

In environmental science, researchers are experimenting with new techniques and technologies that allow them to learn more about our ecosystems and the interactions that take place within it.

A recent review published in Trends in Environmental Analytical Chemistry by Kevin R. Tucker, a leading researcher from Southern Illinois University Edwardsville, explored this topic by investigating the application of high-resolution mass spectrometry imaging (HR–MSI) in environmental research (1).

World water day concept, idea of saving water and protecting world environment. Generated with AI. | Image Credit: © xuan - stock.adobe.com

Mass spectrometry (MS) has played a vital role in recent research in environmental analysis. Most of the recent studies published in academic journals explored how MS, when coupled with inductively coupled plasma (ICP-MS), can quantify elemental mapping of plants and other elements in cells and biotissues (2,3). Traditionally, MS-based techniques required the homogenization of samples prior to analysis. Although this process can be effective at quantification, it often falls short in discerning information regarding the spatial distribution of analytes (1).

However, HR–MSI can alleviate this issue. The review article highlights how high-resolution MS, when combined with advanced imaging techniques, allows researchers to obtain two-dimensional (2D) spatial information about unlabeled analytes. This not only enables the identification of these substances, but it also provides insight into their distribution and relative concentration changes following pollutant exposure (1).

There are several areas where HR–MSI is contributing in a meaningful way, which Tucker and his team delved into in the article. Currently, HR–MSI is making an impact in non-target analysis, wastewater treatment plant (WWTP) constituents, and perfluorinated alkyl substances (PFAS) toxicology (1).

Starting with non-target analysis (NTA), the researchers discussed how HR–MSI offers a unique advantage by allowing researchers to detect and identify a broad spectrum of unknown contaminants without prior knowledge of their presence (1). This is particularly valuable in environmental samples, where the complexity and diversity of potential pollutants often pose significant challenges to traditional analytical methods (1). By providing a 2D map of analytes within a sample, HR–MSI helps researchers pinpoint areas of concern with precision.

The application of HR–MSI to wastewater treatment plants (WWTPs) is another area of growing interest. WWTPs are crucial in mitigating the release of pollutants into the environment, but they also serve as a source of complex chemical mixtures, some of which could be harmful (1). HR–MSI allows for the detailed analysis of these constituents, offering insights into the effectiveness of treatment processes and the fate of residual contaminants (1). By visualizing the spatial distribution of these substances, researchers can better understand how they interact within the treatment system and identify potential areas for improvement (1).

And finally, in per-and polyfluoroalkyl substances (PFAS) analysis, HR–MSI provides a powerful tool for studying PFAS distribution in environmental matrices, aiding in the identification of hotspots and understanding how these substances move through ecosystems (1).

HR–MSI is a relatively new advancement in environmental analysis, but as the research team shows, it is impacting several key areas. Because it is still relatively new, the utility of HR–MSI is expected to expand.

One promising development on the horizon is the integration of ion mobility spectrometry (IMS) with HR–MSI. IMS adds another layer of separation to MS, enabling even more detailed analysis of complex mixtures (1). This combination could further enhance the capabilities of HR–MSI, allowing for even more precise identification and quantification of contaminants in environmental samples.

References

(1) Selby, K. G.; Hubecky, E. M.; Zerda-Pinto, V.; et al. Mass Spectrometry Imaging for Environmental Sciences: A Review of Current and Future Applications. Trends Environ. Anal. Chem. 2024, 42, e00232. DOI: 10.1016/j.teac.2024.e00232

(2) The Editors of Spectroscopy, What’s New in ICP-MS for Environmental Analysis? Spectroscopy 2024, 39 (3), 8–10. https://www.spectroscopyonline.com/view/what-s-new-in-icp-ms-for-environmental-analysis

(3) Wetzel, W. Accurate Elemental Mapping of Plant Tissues Using LA-ICP-TOF-MS. Spectroscopy. Available at: https://www.spectroscopyonline.com/view/accurate-elemental-mapping-of-plant-tissues-using-la-icp-tof-ms (accessed 2024-08-13).