Mass spectral characterization of ergot alkaloids by electrospray ionization, hydrogen/deuterium exchange, and multiple stage mass spectrometry: usefulness of precursor ion scan experiments

Abstract

Six ergot alkaloids belonging to the lysergic acid derivatives (ergonovine (EGN) and methysergide hydrogen maleinate (MHM)) and peptide-type derivatives (ergocristine (EGR), ergotamine (EGT), ergocornine (EGC) and alpha-ergokryptine (EGK)) were studied by positive electrospray tandem mass spectrometry. The fragmentation mechanisms of these compounds were studied by collision-induced dissociation (CID) using triple quadrupole and ion trap mass spectrometers, and the nature of the major product ions further confirmed by hydrogen/deuterium (H/D) exchange experiments. A common abundant product ion at m/z 223 was characteristic of the two classes of ergot alkaloids. Therefore, a precursor ion scan of m/z 223 that triggers information data acquisition (IDA) in combination with CID experiments was used to identify other potential ergot alkaloids. Using this approach, it was possible to confirm the presence of ergosine, another peptide-type ergot alkaloid, in a rye flour extract at trace levels.

Multi-mycotoxin Analysis of Finished Grain and Nut Products Using Ultrahigh-Performance Liquid Chromatography and Positive Electrospray Ionization–Quadrupole Orbital Ion Trap High-Resolution Mass Spectrometry

“…Five A+2 isotopes, including ergometrine, the ergot alkaloid in this study with the lowest molecular weight, could not be detected at 1 ng/mL. In contrast, ochratoxin A, the only mycotoxin in this study consisting of 35 Cl and 37 Cl isotopes, produced a fourth molecular isotope that could be reliably identified at all three concentration levels. Table 3.…”

“…The use of Q-orbital trap MS technology has been evaluated thoroughly by applying a validation for mycotoxins in grain and nut products comparable to a previous LC-MS/MS study, evaluating reference and actual food samples, and providing high-accuracy mass fragmentation information that was useful for mycotoxin identification. Future research will include 30 and Mohammed et al 31 with experimental agreement and some modifications by studies performed in this work as well as by Mulac et al 32 and Arroyo-Manzanares et al 35 If protonation occurs at the amide bond 1A, two fragmentation pathways (A,B) are possible: (A) α-cleavage of the amide bond to form 3A, 3B, or (B) β-cleavage of the amide bond in 2, which can lose NH 3 to form 3A, 3B. Structures 3A, 3B can either lose CO to 5 or undergo rearrangement to 4.…”

“…Previous LC-MS/MS studies have provided detailed fragmentation schemes of these peptide-like indole alkaloids, resulting in the formation of two characteristic lysergic acid moiety products (m/z 223 and 208), typically used for quantitation and identification. A possible fragmentation pathway from the precursor ion, ergocornine, to its various products is illustrated in Figure 4, based on previous LC-MS/MS studies 34,35 and supported by high-resolution/ high-mass-accuracy DDMS 2 analysis. Fragmentation begins by protonation of the amide bond in 1A (m/z 562.30240), leading to two possible pathways involving α-and β-cleavage of the amide bond, and then the formation of the ergoline products 2 (m/z 268.14435) and 12, and 3A (m/z 251.11789), respectively.…”

An integrated targeted and untargeted approach for the analysis of ergot alkaloids in cereals using UHPLC – hybrid quadrupole time-of-flight mass spectrometry

“…2014; Mohamed et al, 2006b) and indicated that all derivatives give rise mainly to fragment ions with m/z 223 and 208 corresponding to the four-ring system of the lysergic moiety and its demethylated counterpart, respectively. In total, 19 different compounds demonstrated a fragmentation pattern that pointed to ergot alkaloids.…”

“…Analytical methods for the determination of ergot alkaloids include thin layer chromatography (TLC) (Salvat and Godoy, 2001), capillary electrophoresis (CE) (Franch and Blaschke, 1998), enzyme linked immunosorbent assay (ELISA) (Hill et al, 2001), gas chromatography (GC) with electron capture detection (ECD) (Barrow and Quigley, 1975), liquid chromatography (LC) with ultraviolet (Veress, 1993), fluorescence (Komarova and Tolkachev, 2001a;Storm et al, 2008) or mass spectrometric (MS) (Diana di Mavungu et al, 2012;Burk et al, 2006;Kokkonen and Jestoi, 2010;Krska et al, 2008a;Mohamed et al, 2006b) detection. Over the last decade, LC-MS has become a dominant tool for mycotoxin determination, and has provided an unequivocal identification of ergot alkaloids in various matrices (Diana di Mavungu et al, 2012;Friedrich et al, 2004;Kokkonen and Jestoi, 2009;Krska et al, 2008;Lehner et al, 2005;Mohamed et al, 2006a;Mohamed et al, 2006b). Due to its simple operation and low cost, ergot alkaloid analysis is currently mainly conducted using a triple-quadrupole (QqQ) MS system.…”