Emily Crawford   Emily Crawford completed her B.S. in Chemistry in 2023 at the Georgia Institute of Technology in Atlanta, GA. She is currently an analytical chemistry Ph.D. candidate at the University of North Carolina at Chapel Hill in Dr. Erin Baker’s laboratory. Here, her research focuses on optimizing separation and mass spectrometry techniques to assess the effects of pharmaceutical pollution on the environment.

Assessing Antidepressant Pharmaceuticals in the Environment through the Development of a Multidimensional Liquid Chromatography-Ion Mobility Spectrometry-Mass Spectrometry Library

Antidepressant (AD) medications are globally prescribed to alleviate depression symptoms by altering neurotransmitter reuptake in the brain. Up to 90% of an orally administered AD dose is excreted from the body as either the parent chemical or pharmacologically active metabolites which remain active even at low concentrations. These molecules are not currently removed by wastewater treatment plants (WWTPs), posing great environmental and ecological concerns. To understand exposure risks, we developed methods to quantify 26 parent ADs and 16 metabolites in surface water with liquid chromatography, ion mobility spectrometry, and mass spectrometry (LC-IMS-MS). Read More
This work provides the first multidimensional LC-IMS-MS reference library for ADs and their metabolites, enabling targeted suspect screening in Skyline (MacCoss Lab Software, v. 23.1) and enhancing confidence in identifications within complex samples. The library was used to evaluate AD pollution in North Carolina surface water and is publicly available to all Skyline users for broader AD analysis. Water samples were collected from five locations across central North Carolina: four directly downstream from WWTP discharge pipes, and a fifth from a recreational lake with no issued permits for wastewater discharge. Each sample, as well as calibration standards and method blanks, were spiked with a mixture of deuterated standards, concentrated using solid phase extraction (SPE), and analyzed using an Agilent 1290 UHPLC coupled with an Agilent 6560 IM-QTOF. Identifications were made on Skyline by comparing LC retention times, collision cross section values, fragmentation patterns, and m/z ratios to the multidimensional AD library. Each detection was quantified by comparing light-to-heavy signal ratios against the calibration curve. Out of the 42 pharmaceuticals present in the library, ten ADs and six metabolites were detected in the surface water samples at concentrations ranging from ng/L to µg/L. Since previous studies indicate behavioral disturbances and altered swimming abilities in both fish and amphipods exposed to ADs at ng/L levels, these results demonstrate the urgent need for improvements in WWTP practices.