Characterization of N-acyl-D-biotinols by particle-beam liquid chromatography-mass spectrometry. An alternative to probe mass spectrometry for thermally labile samples.
In the course of preparing biotin-labeled nucleic acid probes, it was necessary to verify structures of intermediate N-acyl derivatives of biotinol. Characterization by mass spectrometry (MS) involved use of particle-beam liquid chromatography (LC)-mass spectrometry MS to supplement standard heated-solids probe techniques. The probe data for a sample of N-toluoylbiotinol indicated it to be a mixture of mono- and di-toluoylbiotinols which was inconsistent with other analytical information. Analysis of the same sample by LC-MS on a reversed-phase column with a water-acetonitrile gradient showed a single major peak with spectrum consistent with that for the monotoluoyl species. These results suggested that a thermal transacylation reaction might be occurring in the probe during heating prior to volatilization and ionization. This was confirmed by heating the sample to 200 degrees C and then repeating the LC-MS analysis to find peaks now present for biotinol and ditoluoylbiotinol as well as the starting material. These results demonstrate the value of particle-beam LC-MS as a technique for obtaining electron-impact mass spectra of thermally sensitive compounds.
Chipman
G R
GR
Amoco Corporation, Amoco Research Center, Naperville, IL 60566.
Cruickshank
K A
KA
D001710:Biotin / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry; D002853:Chromatography, Liquid / Q000379:methods*; D004355:Drug Stability; D006358:Hot Temperature; D013058:Mass Spectrometry / Q000379:methods*
D001710:Biotin