Mass spectrometry continues to play an important role in the discovery, development, and registration of agricultural chemicals. This talk will provide an overview of several of these areas of application, describing the use of novel separation techniques including supercritical fluid chromatography (SFC) and capillary electrophoresis (CE) in agrochemical R&D. We will also present the application of isotopic labeling approaches, ion mobility mass spectrometry (IM-MS), and alternate fragmentation mechanisms such as ultraviolet photodissociation (UVPD) and electron-induced dissociation (EID) in the identification of impurities and metabolites. As a part of our search for new actives with favorable environmental profiles, a series of environmental studies are often conducted early in discovery process to generate preliminary data on biotransformation pathways in soils, plants, and various in vitro cell models. This work is generally performed prior to the availability of a radiolabel, and the detection of the resulting xenobiotic metabolites is often aided by the use of data reduction methods including mass defect filtering (MDF), isotope filtering, sample/control comparison, and screening for predicted metabolites. These approaches can be enhanced through the incorporation of stable-label isotopes (13C, 15N, or deuterium), which can provide a unique isotopic fingerprint to be monitored in the presence of complex matrices. We will show examples where environmental samples were analyzed on ultra-high resolution LC/MS systems and processed using software packages that can filter for the unique isotopic pattern of the applied parent material. Registration of a new agrochemical requires the determination of its fate in several environmental systems including; plant & animal metabolism, photolysis, soil degradation, hydrolysis, and water sediment. LC/MS plays a critical role in the structural elucidation of the complex trace level metabolites generated in these studies. Modern LC/MS instrumentation combining high resolution mass spectrometry with tools including micro and nano-scale separations, supercritical fluid chromatography, and ion mobility separations have been applied to speed the identification of these challenging trace level environmental degradates. In this presentation we will provide a brief introduction of the several of these techniques, and how they can be applied to the identification of impurities and environmental metabolites.

Novel mass spectrometry tools to speed the identification of metabolites and impurities

2019 Fall National Meeting

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