Liquid chromatography-mass spectrometric detection (LC-MSD) was used to determine the concentration of emodin in water samples from ephemeral and permanent ponds at Carroll University’s Greene Field Station. These ponds are home to tadpoles, whose development is impacted by the presence of emodin. A high abundance of emodin in pond water correlates to liver damage and mortality of amphibians in those environments. Emodin is an anthraquinone-like compound that is released into the water and sediment when buckthorn (pervasive invasive plant) leaves fall and decompose. The shallow, temporal ponds are created in early spring by melting snow. The permanent ponds present in late summer are typically deeper and spring fed. Emodin was extracted from pond water samples by solid phase extraction (SPE) and analyzed by LC-MSD using purpurin as the internal standard. The quadrupole MSD was run in API-ESI, SIM, negative ion mode for m/z ions at 256 amu (purpurin) and 270 amu (emodin). An isocratic method using 0.1% formic acid and acetonitrile resulted in a reproducible retention time of 20 minutes for emodin. The method was validated through replicate analysis of standards for reproducibility and sensitivity. The limit of detection (LOD), 9.7 ug/L, and limit of quantification (LOQ), 32 ug/L, were determined by the best-fit-line method. The SPE method was tested through a recovery study resulting in an average recovery of 16 percent. The low recovery was likely due to a cosolvent effect in the emodin sample solution as it contained high levels of methanol. Further method development needs to be completed for the SPE method before pond water samples can be analyzed.

LC-MSD analysis of emodin in pond water – ecological implications

ACS Spring Meeting 2021

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