Non-Targeted Suspect Screening Strategies Using Low Resolution LC-MS-MS

Non-Targeted Compound Screening
Oral Presentation

Prepared by

Contact Information: [email protected]; 951-653-3351


Over the last few decades much data has been collected using high resolution accurate mass (HRAM) instruments. This technique has provided us with volumes of information about contamination of new chemicals that were not being detected simply because no one was looking for them previously. An indirect benefit of this data is that it has provided insights into key areas that benefit Low-Res MS users. We can now observe common fragmentation pathways under collisionally activated dissociation conditions allowing in-silico predictions of non-targeted suspect fragmentation when no transition data is available. This technique has been applied to perfluorinated compounds which produce distinct product ions and neutral losses. Exploiting information gathered under HRAM can tremendously narrow a list of suspect candidates when collecting data even for Low-Res MS users. Another key piece of information that has been learned is what eluent compositions promote or disrupt electrospray ionization (ESI) and contribute ultimately to the response of an analyte. This also is important for High Res MS users as well because a non-targeted suspect will never be detected if LC or ESI source conditions prevent ionization.
New derivatization techniques are also presented as a tool to isolate certain chemical classes that are normally not amenable to ESI. One particularly useful derivatization technique is sulfonation of aromatic hydrocarbons because it is fast, produces high yield, and produces readily ionized products under most HPLC conditions. Also, because sulfonation is an aggressive reaction, many other compound classes are simply broken down. Aromatic sulfonates produce a distinct [SO3]- product ion at 80m/z so compounds can be screened on that basis. This technique has been applied to detect compound classes such as polynuclear aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and others at trace levels using ESI.