Current Status and Recent Advances in the Chromatography and Mass Spectrometry of Ecdysteroids

Evershed, Richard P.; Kabbouh, Mohamed; Prescott, Mark; Maggs, James L.; Rees, Huw H.

doi:10.1007/978-1-4684-8062-7_10

Cited by 6 publications

(3 citation statements)

References 23 publications

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“…In the NP-LC of these compounds, both adsorbent phases or chemically bonded polar phases, and apolar, chemically bonded stationary phases can be used. Silica, the most widely applied stationary phase, results in outstanding resolution in the separation of ecdysteroids, as confirmed in the literature [11][12][13]. The most general mobile phases on silica are ternary systems based on dichloromethane, with isopropanol as polar modifier.…”

Section: Introductionmentioning

confidence: 88%

Dynamic On-Column Eluent Modification: A Novel Strategy for Peak Resolution Enhancement. Application to the Preparative Separation of Ecdysteroid Isomers

Hunyadi

Kalász

Báthori

2008

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A novel LC method was applied to enhance the peak resolution of two ecdysteroids: 20-hydroxyecdysone and its 3-epimer. An isocratic solvent system of methanol-water (6:4, v/v) was used on a C18 column, and 100 lL of water was injected during the development in such a manner that the eluted solvent peak appeared exactly between the two overlapping peaks. This resulted in the increased retardation of the later-eluted peak, and in a good separation of the two compounds within 4.5 min.

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Section: Introductionmentioning

confidence: 88%

Dynamic On-Column Eluent Modification: A Novel Strategy for Peak Resolution Enhancement. Application to the Preparative Separation of Ecdysteroid Isomers

Hunyadi

Kalász

Báthori

2008

Chroma

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“…' Fast-atom bombardment mass spectrometry (FAB-MS) provides the most widely applicable ionization technique for the mass spectrometric investigation of ecdysteroids (see Ref. 4 and Refs therein). The technique is applicable to free ecdysteroids, polar metabolites and apolar and polar conjugates.…”

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confidence: 99%

“…3 Since the concentration of ecdysteroids in biological tissues and fluids is often low, mass spectrometry has played a central role in their detection and characterization (see Ref. 4 and Refs therein). The usefulness of electron ionization (EI) for the study of ecdysteroids is limited by their low volatility and tendency to dehydrate in the absence of derivatization."'…”

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confidence: 99%

Metastable ions arising from pseudomolecular [M  H]⁻ ions produced by fast‐atom bombardment negative‐ion mass spectrometry of ecdysteroids

Evershed

Prescott

Kabbouh

et al. 1989

Rapid Comm Mass Spectrometry

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Metastable ions arising from pseudomolecular [M-H]- ions produced by fast-atom bombardment negative-ion mass spectrometry of a range of free ecdysteroids, ecdysteroid conjugates and polar metabolites were investigated by means of linked scanning at constant B/E. Free ecdysteroids displayed daughter-ion spectra which allow 20-hydroxyecdysteroids and ecdysteroids lacking C-20 hydroxylation to be readily distinguished. The ejection of acetic acid from acetylated ecdysteroids was also readily detectable. Characteristic metastable-ion decomposition of ecdysteroid acids was not observed, presumably as a result of charge localization. High-mass daughter ions were also lacking in the case of phosphate conjugates.

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Cyclic boronates in the mass spectrometry of ecdysteroids

Vaisar¹,

Píš²

1993

Rapid Comm Mass Spectrometry

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For the structural elucidation of ecdysteroids a reaction with phenylboronic acid has been employed. This reaction takes place exclusively on the C20,C22 diol moiety, thus facilitating fast and easy detection of this moiety in the molecule of ecdysteroid. This derivatization also redirects fragmentation to C17/C20 bond cleavage with charge retention on both fragments enabling assessment of the structure both of the steroid nucleus and of the side-chain. Possible reaction of phenylboronic acid with the diol moiety of the glycosyl group of the glycoside of ecdysteroid, producing di-adduct, is demonstrated; participation of the 5p-hydroxy group of 58,20-dihydroxyecdysone in the formation of such a di-adduct is discussed; and the role of the enol form of the 6-carbonyl group is proved.Ecdysteroids are polyhydroxylated steroid compounds, which take part in the regulation of developmental processes of invertebrates. Many compounds of this structural type have also been isolated from plants. ' Structure elucidation of these polyfunctional substances is usually accomplished by spectral methods, mainly nuclear magnetic resonance (NMR) and mass spectrometry because of the low amounts of the individual compounds that are available. Mass spectrometry is especially suitable because it requires only a very small amount of sample. Its combination with NMR and infra-red spectroscopy can give a large amount of information about the structure of the compound under investigation.Fast-atom bombardment (FAB) mass spectra of ecdysteroids give molecular weight information' and further information can be obtained from the spectra of daughter ions from collision-activated dissociation (CAD) in either the positive-or negative-ion m~d e .~.~ On the other hand, in an electron-impact (EI) mass spectrum the molecular ion is usually missing or is very weak, but from extensive fragmentation by sequential losses of molecules of water, cleavage of bonds C20/C22 for those compounds with a C20,C22 diol group or of bonds C17/C20 for compounds without this group as well as from steroid nucleus fragmentation, the main structural features can be Desorption chemical ionization (DCI) mass spectra can provide both molecular weight information and structural information from the extensive fragmentation that can be observed. However, in order to achieve both kinds of information it is necessary to set the experimental conditions precisely .'Another way of obtaining structural information is via the preparation of derivatives of ecdysteroids in order to change the mass spectrum in a defined way. For this purpose the derivatization reaction should fulfil the following criteria: it should be quantitative, it should produce only one product, and a mass spectrum should give information which cannot be obtained from the spectrum of an underivatized ecdysteroid. Trimethylsilylation has been used for increasing the volatility for GC/MS analysis,' while acetonides and Author to whom correspondence should be addressed. acetates have been prepared for elucidation of...

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Current Status and Recent Advances in the Chromatography and Mass Spectrometry of Ecdysteroids

Cited by 6 publications

References 23 publications

Dynamic On-Column Eluent Modification: A Novel Strategy for Peak Resolution Enhancement. Application to the Preparative Separation of Ecdysteroid Isomers

Dynamic On-Column Eluent Modification: A Novel Strategy for Peak Resolution Enhancement. Application to the Preparative Separation of Ecdysteroid Isomers

Metastable ions arising from pseudomolecular [M  H]⁻ ions produced by fast‐atom bombardment negative‐ion mass spectrometry of ecdysteroids

Cyclic boronates in the mass spectrometry of ecdysteroids

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Current Status and Recent Advances in the Chromatography and Mass Spectrometry of Ecdysteroids

Cited by 6 publications

References 23 publications

Dynamic On-Column Eluent Modification: A Novel Strategy for Peak Resolution Enhancement. Application to the Preparative Separation of Ecdysteroid Isomers

Dynamic On-Column Eluent Modification: A Novel Strategy for Peak Resolution Enhancement. Application to the Preparative Separation of Ecdysteroid Isomers

Metastable ions arising from pseudomolecular [M  H]− ions produced by fast‐atom bombardment negative‐ion mass spectrometry of ecdysteroids

Cyclic boronates in the mass spectrometry of ecdysteroids

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Metastable ions arising from pseudomolecular [M  H]⁻ ions produced by fast‐atom bombardment negative‐ion mass spectrometry of ecdysteroids