Margaret A McCooeye

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A high-field asymmetric waveform ion mobility spectrometry (FAIMS)-based method for the determination of the mycotoxin zearalenone (ZON) and its metabolites alpha-zearalenol (alpha-ZOL), beta-zearalenol (beta-ZOL), and beta-zearalanol (beta-ZAL), in a cornmeal (maize) matrix is described. Detection limits achieved using the FAIMS device coupled with(More)
A high-resolution mass spectrometric detection method is described for the identification of key metabolites in the selenium pathway in selenium enriched yeast. Iodoacetic acid (IAA) was used as the derivatizing reagent to stabilize the selenols. Oxidized forms of selenocysteine (Se-Cys), selenohomocystine (Se-HCys), selenoglutathione (Se-GSH),(More)
Morphine and codeine have been identified and measured in a human urine matrix using high-field asymmetric waveform ion mobility spectrometry (FAIMS) in a tandem combination with electrospray ionization (ESI) and mass spectrometric (MS) detection. The addition of helium to the nitrogen carrier gas resulted in a substantial improvement in the sensitivity of(More)
A suite of five ephedra-containing dietary supplement Standard Reference Materials (SRMs) has been issued by the National Institute of Standards and Technology (NIST) with certified values for ephedrine alkaloids, synephrine, caffeine, and selected toxic trace elements. The materials represent a variety of natural, extracted, and processed sample matrixes(More)
A method is described for the determination of ephedrine (E) and pseudoephedrine (PE) and their metabolites norephedrine (NE), norpseudoephedrine (NPE), methylephedrine (ME), and methylpseudoephedrine (MPE) alkaloids in natural health products by flow injection-electrospray ionization-high field asymmetric waveform ion mobility spectrometry-mass(More)
Here, we describe a new application of ultra-performance liquid chromatography coupled with an electrospray ionization quadrupole time-of-flight mass spectrometry operating in MS(E) mode (UPLC-QTOF-MS(E)) for the sensitive, fast, and effective characterization of alkaloids in goldenseal (Hydrastis canadensis). This approach allowed identification of(More)
Liquid chromatography coupled to multistage mass spectrometry (LC-MS(n)) is being used increasingly in pharmaceutical research and for quality control in herbal medicines because of its superior sensitivity and selectivity. In this study, a rapid, high-resolution liquid chromatography-mass spectrometry (LC-MS(n)) method was developed to separate and(More)
The National Institute of Standards and Technology, the U.S. Food and Drug Administration, Center for Drug Evaluation and Research and Center for Food Safety and Applied Nutrition, and the National Institutes of Health, Office of Dietary Supplements, are collaborating to produce a series of Standard Reference Materials (SRMs) for dietary supplements. A(More)
A method for accurate determination of ephedrine (E) alkaloids in natural health products (NHP) is described. The NIST dietary supplement standard reference materials (SRMs) were selected for these studies. These SRMs comprise ground Ma Huang herb (Ephedra sinica Stapf.), a spray dried extract of the former, and commercial formulations derived from gel caps(More)
Absolute quantitation of peptides/proteins in dilute calibration solutions used in various diagnostic settings is a major challenge. Here we report the absolute quantitation of peptides by non-species-specific isotope dilution liquid chromatography-inductively coupled plasma mass spectrometry (ID LC-ICPMS) based on stoichiometric Eu tagging. The method was(More)