Many molecules in the Ag Chem arena can have the same exact mass and empirical formula but are structurally different. This can lead to false positives in screening assays, as well as difficulties during structure elucidation. For example, 2,4-dichlorophenoxyacetic acid, 2, 3-dichlorophenoxy acetic acid, methyl 3,5-dichloro-4-hydroxybenzoate, and 3,6-dichloro-2-methoxybenzoic acid (dicamba), all have the same exact monoisotopic mass (219.969406 Da) and empirical formula (C8H6Cl2O3) but all are structurally different. In many cases chromatographic separation can be used to differentiate structurally similar molecules. Fragmentation analysis is another way to differentiate these chemistries. Examples of how accurate mass spectrometry coupled with fragmentation analysis will be presented. Utilization of a SciEx 5600 Qtof and a SciEx 4000 Q-trap to confirm structures will be compared.

Use of accurate mass instrumentation for the differentiation of molecules with the same exact mass

246th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.