Analysis of anabolic steroids in urine by gas chromatography–microchip atmospheric pressure photoionization-mass spectrometry with chlorobenzene as dopant

• Photoionization is used to connect GC to MS.
• A novel microchip is the key component in GC–μAPPI-MS.
• Radical cations are produced with minimal fragmentation, unlike in GC–EI-MS.
• GC–μAPPI-MS is proven highly sensitive and applicable for doping control.

A gas chromatography–microchip atmospheric pressure photoionization-tandem mass spectrometry (GC–μAPPI-MS/MS) method was developed for the analysis of anabolic androgenic steroids in urine as their trimethylsilyl derivatives. The method utilizes a heated nebulizer microchip in atmospheric pressure photoionization mode (μAPPI) with chlorobenzene as dopant, which provides high ionization efficiency by producing abundant radical cations with minimal fragmentation. The performance of GC–μAPPI-MS/MS was evaluated with respect to repeatability, linearity, linear range, and limit of detection (LOD). The results confirmed the potential of the method for doping control analysis of anabolic steroids. Repeatability (RSD < 10%), linearity (R2 ≥ 0.996) and sensitivity (LODs 0.05–0.1 ng/mL) were acceptable. Quantitative performance of the method was tested and compared with that of conventional GC–electron ionization-MS, and the results were in good agreement.