Application of Ambient Mass Spectrometry for the Detection of Emerging Organic and Inorganic Environmental Contaminants

Rapid, direct analysis of environmental contaminants is important not only for ecology and environmental safety, but also for human health, and researchers working in these areas are in need of cutting-edge analytical solutions. Chemical compounds found in cosmetic products and metal species are of increased interest, as they have become persistent environmental pollutants. As most analyses targeting environmental species are labor-intensive, a direct analysis solution based on mass spectrometry would be quite novel. Desorption electrospray ionization mass spectrometry (DESI-MS) is capable of trace-level detection of cosmetic chemicals in a matter of seconds. Additionally, little to no preparation is typically needed prior to analysis of most samples. Moreover, coupled with portable instrumentation, this technique could be suitable for on-site environmental analysis without removal of the sample from its native state and location. Heavy metals in aquatic environments can also lead to soil and vegetation contamination, as well as accumulation in animal species. In regards to metals analysis, no ambient MS techniques have been applied for the investigation of trace level contamination. While analysis of metals themselves would be problematic, we propose the use of specially-selected chelators to help turn the target analytes into ionizable complexes. Paper spray ionization mass spectrometry (PSI) is a combination of paper chromatography and electrospray ionization and is capable of rapid detection of metal-complexes. Due to the current and changing needs of environmental analysis, effective techniques that are robust while realizing the inherent advantages of MS detection are of interest. In this work, chemicals found in cosmetic compound are selected as a model system for emerging organic environmental contaminants, while free metal ions are selected as a model system for emerging inorganic environmental contaminants. DESI-MS is demonstrated to be a rapid and reliable technique for analyzing these cosmetic chemicals with minimal sample preparation. Special focus was given to the investigation these chemicals as trace residues and as ingredients in authentic cosmetic formulations. Paper spray ionization mass spectrometry proves to be a valid technique for the rapid detection of pre-formed and real-time metal-ligand complexes. These metal-ligand complexes were also detected in authentic contaminated water samples