Method optimization of the simultaneous detection of B12 congeners leading to the detection of a novel isomer of hydroxycobalamin in seawater.
Rapid Commun Mass Spectrom
; 36(23): e9401, 2022 Dec 15.
Article
em En
| MEDLINE
| ID: mdl-36104947
ABSTRACT
RATIONALE More than half of surveyed microalgae and over 90% of harmful algae have an obligate requirement for vitamin B12 , but methods for directly measuring dissolved B12 in seawater are scarce due to low concentrations and rapid light-induced hydrolysis. METHODS:
We present a method to detect and measure the four main congeners of vitamin B12 dissolved in seawater. The method includes solid-phase extraction, separation by ultrahigh-performance liquid chromatography and detection by triple-quadrupole tandem mass spectrometry utilizing an electrospray ion source. This method was applied to coastal field samples collected in the German Bay, Baltic Sea and the Danish Limfjord system.RESULTS:
The total dissolved B12 pool ranged between 0.5 and 2.1 pM. Under ambient conditions methyl-B12 and adenosyl-B12 were nearly fully hydrolyzed to hydroxy-B12 in less than 1 h. Hydroxy-B12 and a novel, corresponding isomer were the main forms of B12 found at all field sites. This isomer eluted well after the OH-B12 peak and was also detected in commercially available OH-B12 . Both compounds showed very high similarity in their collision-induced dissociation spectra.CONCLUSIONS:
The high instability of the biologically active forms of Me-B12 and Ado-B12 towards hydrolysis was shown, highlighting the importance of reducing the duration of the extraction protocol. In addition, the vitamin B12 pool in the study area was mostly comprised of a previously undescribed isomer of OH-B12 . Further studies into the structure of this isomer and its bioavailability are needed.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Água do Mar
/
Hidroxocobalamina
Tipo de estudo:
Diagnostic_studies
Idioma:
En
Revista:
Rapid Commun Mass Spectrom
Ano de publicação:
2022
Tipo de documento:
Article