Liquid chromatography mass spectrometry of dexamethasone and betamethasone

Cairns, Thomas; Siegmund, Emil G.; Stamp, John J.; Skelly, Jerome P.

doi:10.1002/bms.1200100317

Cited by 28 publications

(8 citation statements)

References 14 publications

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“…On the basis of our data, and assuming equilibrium gas-phase chemistry, we conclude that the PA of most carbamates must be close to that of ammonia (854 kJ/mol [50]) and even closer to that of nicotinic acid (not available). The fact that complex formation occurs with most carbamates is in line with the idea [13,17,251 that the carbamate group provides the site of protonation. Moreover, the carbamates that do not generate complex ions (aminocarb, carbendazim, pirimicarb) have structural features that may provide a different site of protonation: a dimethyl amino group in aminocarb and an aromatic ring nitrogen in carbendazim and pirimicarb would make these compounds more basic.…”

Section: Positive Ion Thermospray Spectrasupporting

confidence: 65%

Ion formation of N-Methyl carbamate pesticides in thermospray mass spectrometry: The effects of additives to the liquid chromatographic eluent and of the vaporizer temperature

Honing

Barceló

Baar

et al. 1994

J. Am. Soc. Mass Spectrom.

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The effects of three additives-ammonium acetate, ammonium formate, and nicotinic acid-to the liquid chromatographic (LC) eluent and of the vaporizer temperature on the ion formation of N-methyl carbamate pesticides in thermospray (TSP) mass spectrometry was investigated by using filament- or discharge-assisted ionization. Nineteen carbamates and 12 of their known environmental degradation products were used as model compounds. The additives cause a strong reduction in the abundance of the characteristic fragment ions [M + H - CH3NCO](+) and [M - H - CH3NCO](-) for some of the carbamates. The addition of nicotinic acid reduces the quasimolecular ion intensity and, in most cases, produces nicotinic acid adduct ions. The addition of ammonium acetate or ammonium formate increases the intensity of the quasimolecular ion and in most cases produces a base peak for the ammonium adduct ion. The combination of a suppression of fragmentation and an enhancement of quasimolecular ion formation produces an overall gain in sensitivity. As to more specific effects, the addition of the ammonium salts reduces the intensity of M(-•) with the chlorinated carbamate barban and suppresses the formation of "odd" adduct ions in the TSP mass spectra of most other carbamates. Monitoring the intensity of the fragment and the quasimolecular ion signal as a function of the probe stem temperature, and the related probe tip temperature, proved to be an easy method to study the thermal degradation of the carbamates. This monitoring procedure showed that methiocarb and its sulfone already suffer from thermal degradation at a stem temperature of 90°C and that these compounds will therefore present problems in quantitation with LC/TSP mass spectrometry.

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Section: Positive Ion Thermospray Spectrasupporting

confidence: 65%

Ion formation of N-Methyl carbamate pesticides in thermospray mass spectrometry: The effects of additives to the liquid chromatographic eluent and of the vaporizer temperature

Honing

Barceló

Baar

et al. 1994

J. Am. Soc. Mass Spectrom.

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“…Observed ions included (M + H)+ and (M + H -H,O)+ from the undegraded C2,-steroid but also protonated molecular ions from the degraded 17-ketone (96).…”

Section: A Free Steroidsmentioning

confidence: 99%

Chemical ionization mass spectrometry of steroids and other lipids

Lin¹,

Smith²

1984

Mass Spectrometry Reviews

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“…Isotopic ratio mass spectrometry (GC‐C‐IRMS) was also used to distinguish natural endogenous CoSTs from their exogenous analogues 50. But further developments in LC‐MS51–54 and LC‐MS n 55–64 with API techniques permitted significant improvements in terms of sensitivity and specificity, as well as kinetic and metabolism studies 65. The recently introduced ultra‐performance/fast liquid chromatography systems (UPLC) should be an ultimate reason for considering LC‐MS n as the actual and future standard for corticosteroid analysis.…”

Section: The Analysis Of Corticosteroids (Group B2f) With Mass Spectrmentioning

confidence: 99%

Past, present and future of mass spectrometry in the analysis of residues of banned substances in meat‐producing animals

et al. 2007

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A residue is a trace (µg kg −1 , ng kg −1 ) of a substance, present in a matrix. Banned substances, such as growth promoters, which are abused in animal fattening and where this article is focused on, may be divided into four major groups: thyreostats, anabolics or anabolic steroids, corticosteroids and beta-agonists or repartitioning agents. The combination of chromatographic techniques with mass spectrometry (GC-MS n , LC-MS n , etc.) plays a key role in the production of specific results in residue analysis. In this review, the past, present and future of mass spectrometry in this area are discussed in the light of the impact of these substances on human health and the reliable production of analytical results, ready for challenge in a court.

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Liquid chromatography mass spectrometry of dexamethasone and betamethasone

Cited by 28 publications

References 14 publications

Ion formation of N-Methyl carbamate pesticides in thermospray mass spectrometry: The effects of additives to the liquid chromatographic eluent and of the vaporizer temperature

Ion formation of N-Methyl carbamate pesticides in thermospray mass spectrometry: The effects of additives to the liquid chromatographic eluent and of the vaporizer temperature

Chemical ionization mass spectrometry of steroids and other lipids

Past, present and future of mass spectrometry in the analysis of residues of banned substances in meat‐producing animals

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