Quantitative methodology for corticosteroids based on chemical oxidation to electrophilic products for electron capture-negative chemical ionization using capillary gas chromatography-mass spectrometry. I. Assessment of feasibility in the analysis of horse urine for dexamethasone.

The research article reports on a newly developed methodology using capillary column gas chromatography-electron capture-negative chemical ionization-mass spectrometry for the quantitative analysis of corticosteroids like dexamethasone in biological fluids like horse urine.

Introduction

• This study aims to establish an effective way to quantitatively analyse corticosteroids from biological fluids.
• To assess the viability of this approach, the research looked into the analysis of dexamethasone in horse urine after the drug had been administered.

Methodology

• A structurally akin compound, 6 alpha-methylprednisolone, was added to the horse urine as an internal standard.
• The free dexamethasone and the internal standard were extracted from the urine for further analysis.
• The extracted compounds were then oxidized to result in high-electron-affinity 1,4-androstadiene-3,11,17-trione structural analogs. This essentially makes the compounds more responsive to the electron capture process.

Analysis Approach

• The oxidized compounds were then analysed using a capillary column gas chromatography-electron capture-negative chemical ionization-mass spectrometry (GC-ECNCI-MS) method.
• The GC-ECNCI-MS is a method used to completely separate and identify different compounds in a sample.
• In electron capture-negative chemical ionization, an electron is captured by the molecule, and the excess energy leads to fragmentation, which can be tracked by mass spectrometry.

Implication of the research

• This research potentially opens up a new, more sensitive and specific method for the quantitative analysis of corticosteroids in biological fluids.
• Rigorously examining for the presence of corticosteroids like dexamethasone in horse urine, for instance, can prevent potential misuse in equine sports.