The positive identification and quantitiation of compounds in natural product samples typically relies on analytically pure of known standards of known concentration in order to provide reliable comparative data. Unfortunately, for most natural products, standards of analytically pure materials are not readily available. We use gas chromatography-mass spectrometry (GC-MS) in electron impact (EI) mode to identify alkaloids in the extracts of the skins of poison frogs. Unfortunately, the EI spectra of many alkaloid classes tend to give similar specra containing one or two high abundance (30-100%) and a variety of low abundance (&lt;10%) fragments that while specific to the compound, are often difficult to reliably distinguish from background. We are attempting to automate analysis using the NIST-AMDIS analysis package. However, our existing library based largely on tabulated literature data does not contain these low abundance ions, which are critical to positive identification. We are thus constructing an electronic library of authentic, background subtracted electron impact spectra of the over 800 alkaloids thus far identified in poison frogs, using original instrumental datasets and re-examination of archival extracts from the John Daly laboratory at NIH. Our intention is to make this library publicly available and results to date will be presented.

Construction of an electron impact mass spectral library for the automated analysis of poison frog alkaloids

2019 Spring National Meeting

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