Comparison of electrospray ionization and atmospheric pressure photoionization liquid chromatography mass spectrometry methods for analysis of ergot alkaloids from endophyte-infected sleepygrass (Achnatherum robustum)

• Published in: Journal of pharmaceutical and biomedical analysis Vol. 117; pp. 11 - 17
• Main Authors: Jarmusch, Alan K., Musso, Ashleigh M., Shymanovich, Tatsiana, Jarmusch, Scott A., Weavil, Miranda J., Lovin, Mary E., Ehrmann, Brandie M., Saari, Susanna, Nichols, David E., Faeth, Stanley H., Cech, Nadja B.
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 05-01-2016
• Subjects: Achnatherum robustum; Atmospheric Pressure; Atmospheric pressure photoionization; Chromatography, Liquid - methods; Electrospray ionization; Endophyte; Endophytes - chemistry; Ergonovine; Ergot; Ergot Alkaloids - analysis; Lysergic acid amide; Poaceae - microbiology; Spectrometry, Mass, Electrospray Ionization - methods; Tandem Mass Spectrometry - methods; Electrospray ionization; Endophyte; Lysergic acid amide; Ergonovine; Atmospheric pressure photoionization; Ergot; Achnatherum robustum
• ISSN: 0731-7085; 1873-264X
• DOI: 10.1016/j.jpba.2015.08.031

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•Ergot alkaloids are mycotoxins with an array of biological effects.•Here we compare two ionization techniques, APPI and ESI, for analysis of ergots.•Studies were performed with endophyte-infected grasses containing ergots.•APPI demonstrated similar performance to the more commonly used ESI.•These are the first to show the applicability of APPI for analysis of ergots.
Ergot alkaloids are mycotoxins with an array of biological effects. With this study, we investigated for the first time the application of atmospheric pressure photoionization (APPI) as an ionization method for LC–MS analysis of ergot alkaloids, and compared its performance to that of the more established technique of electrospray ionization (ESI). Samples of the grass Achnatherum robustum infected with the ergot producing Epichloë fungus were extracted using cold methanol and subjected to reserved-phase HPLC–ESI–MS and HPLC–APPI–MS analysis. The ergot alkaloids ergonovine and lysergic acid amide were detected in these samples, and quantified via external calibration. Validation parameters were recorded in accordance with ICH guidelines. A triple quadrupole MS operated in multiple reaction monitoring yielded the lowest detection limits. The performance of APPI and ESI methods was comparable. Both methods were subject to very little matrix interference, with percent recoveries ranging from 82% to 100%. As determined with HPLC–APPI–MS quantification, lysergic acid amide and ergonovine were extracted from an A. robustum sample infected with the Epichloë fungus at concentrations of 1.143±0.051ppm and 0.2822±0.0071ppm, respectively. There was no statistically significant difference between these concentrations and those determined using ESI for the same samples.