Related Experiment Video
Updated: May 13, 2026

Using a Cyclic Ion Mobility Spectrometer for Tandem Ion Mobility Experiments
Published on: January 20, 2022
LC/MS/MS of steroids having vicinal diol as electrospray-active boronates
Tatsuya Higashi1, Katsumi Kawasaki, Nagisa Matsumoto
1Faculty of Pharmaceutical Sciences, Tokyo University of Science, Noda, Chiba, Japan. higashi@rs.tus.ac.jp
Abstract:
A derivatization procedure with (3-dimethylaminophenyl)dihydroxyborane (DAPB) was introduced to enhance the detectability of steroids having a vicinal diol in LC/electrospray ionization (ESI)-MS/MS. DAPB reacted with the vicinal diol on the steroids [4β-hydroxycholesterol (4-HCh), pregnanetriol (PT) and 20R,22R-dihydroxycholesterol] in pyridine at 50°C within 1 h. The resulting DAPB-derivatives were highly responsive in ESI-MS operating in the positive-ion mode and gave characteristic product ions during MS/MS, which enabled sensitive detection using a selected reaction monitoring mode; the detection responses of the DAPB-derivatives were increased by 20-160-fold over those of the intact steroids and the limits of detection were in the low femtomole or attomole range. The derivatization procedure was successfully applied to biological sample analysis; the derivatization followed by LC/ESI-MS/MS enabled the specific detection of trace amounts of 4-HCh in human plasma and PT in human urine with a small sample volume, simple pretreatment and short chromatographic run time.
More Related Videos
08:56Synthesis of a Borylated Ibuprofen Derivative Through Suzuki Cross-Coupling and Alkene Boracarboxylation Reactions
Published on: November 30, 2022
08:46Regioselective O-Glycosylation of Nucleosides via the Temporary 2',3'-Diol Protection by a Boronic Ester for the Synthesis of Disaccharide Nucleosides
Published on: July 26, 2018
Related Concept Videos
Hydroboration-Oxidation of Alkenes
Alkylation of β-Diester Enolates: Malonic Ester Synthesis
Regioselectivity and Stereochemistry of Hydroboration
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.
Electrospray Ionization (ESI) Mass Spectrometry
ESI utilizes electrical energy to transfer ions from the liquid phase of the sample into the...
Molecular Orbital Theory II
Preparation of Diols and Pinacol Rearrangement
The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.