LC-MS/MS and GC-MS(/MS) based Steroidomics (subproject 7, DFG research group 1369 “Sulfated Steroids in Reproduction”)

The challenges of steroid analysis are extreme and generally underestimated. One challenge consists in the complexity of steroid metabolism per se. Furthermore, there is a multitude of steroid analytes of diverging concentrations and varying diagnostic significance. Synthesis and catabolism of steroids, as well as reference ranges are age and sex dependent. Sometimes, sample material is only available in limited amounts (e.g. in mice). Routine steroid analysis has been primarily based on commercially available immunoassays. However, major analytical quality issues (e.g. antibody specificity, matrix effects), and lack of agreement with reference methods have started a continuous debate on their accuracy. Analytical methods based on mass spectrometry (MS) currently present the most specific qualitative and quantitative methods for steroid determination. Combination with a chromatographic technique such as liquid chromatography (LC) or gas chromatography (GC) allows for the unbiased multi component metabolomics approach. This presentation will highlight the application of LC-MS/MS as well as GC-MS(/MS) in steroid analysis, showing that both techniques are complementary. LC-MS/MS enables a targeted metabolomics approach, requires minimal sample preparation, and permits high throughput. It is likely to become the routine tool in steroid analysis. Furthermore, soft ionization enables the determination of intact complex steroids, such as steroid conjugates. Though more laborious, GC-MS(/MS) is an extremely powerful research tool since GC has the highest separation power for steroids and GC-MS enables both a non-targeted and targeted metabolomics approach (e.g. non invasive urinary steroid profiling). It requires extremely high expertise which is available only at a few highly specialized laboratories worldwide.

Funding: DFG research group 1369 “Sulfated Steroids in Reproduction”, subproject 7