Our objective is to develop new agrochemical products with favorable environmental profiles. In order to achieve this goal, a series of environmental studies are conducted early in the discovery process to generate preliminary data on biotransformation pathways and rate of metabolism in soils, plants, and various in vitro cell models. These systems can generate multiple trace level metabolites that must be identified to recognize and eliminate actives which could potentially transform into persistent or toxic metabolites in the environment. Many of the metabolites which are generated in these studies are small polar substances that present several analytical challenges.  Recent developments in high resolution mass spectrometry, combined with techniques including ion mobility, SFC, CE, and nano separations, have been applied to these complex problems. We will present selected examples where these approaches have proven essential in the identification and quantitation of metabolites in environmental systems. Examples will show the analysis of challeging environmental samples on several modern LC/MS systems capable of accurate MS and MS/MS measurements including the; Fusion Q-OT-IT (Thermo), 5600 Q-TOF (Sciex), and 6560 Q-TOF (Agilent) coupled with separation techniques including SFC, ion mobility, and capillary electrophoresis.  In early stage discovery, this work is generally performed prior to the availability of a radiolabel. 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 may be additionally enhanced through the incorporation of stable-label isotopes (<sup>13</sup>C, <sup>15</sup>N, or deuterium), which can provide a unique isotopic fingerprint to be monitored in the presence of complex matrices. Data are processed using software packages that can filter for the unique isotopic pattern of the applied parent material, which increases the flexibility, accuracy, and efficiency of our metabolite ID workflows.

High resolution mass spectrometry applications in the identification of polar environmental metabolites to support development of new agricultural products

256th National Meeting (2018)

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