Steroids all share a similar structure, with some sharing the same atomic composition/mass. It is important that our technologies can distinguish between different steroids.
This can be achieved in two ways. First, the measurement of the steroid analytes by the mass spectrometer is preceded by a chromatographic step during which the steroids are physically separated from each other, ensuring that each steroid reaches the mass spectrometer at a unique and specific retention time. Secondly, the mass spectrometers can distinguish different steroids based on their differing masses (mass-to-charge ratios m/z) and/or fragmentation patterns.
Liquid Chromatography tandem-Mass Spectrometry (LC-MS/MS)
Waters Aqcuity LC and Xevo-XS (2019): Waters Aqcuity UPC2 and Xevo-S (2016): Waters Aqcuity LC and Xevo (2010)
Liquid chromatography-mass spectrometry is crucial for the targeted identification and quantification of steroids in bio-fluids. Our high throughput, high-pressure, liquid chromatography technologies achieve typical sample run times of less than 10 minutes, allowing processing of a 96-well plate sample batch in one day. The combination of this high-throughput technology with the superior sensitivity of the Waters Xevo mass spectrometers allows us to investigate suites of steroids at different concentrations within a single sample.
In serum, we can identify and quantify 23 steroids in under 10 minutes which include high concentration steroids such as cortisol (100-600 nM), and low concentration steroids such as DHT (0.1-2.5 nM). The breadth of data compiled from this type of analysis can provide simultaneous information on multiple pathways of steroid metabolism.
In urine, we can identify and quantify 30 steroids in under 20 minutes which covers the wide dynamic range of those observed in urine from less than 10 µg/24 hours to more than 3000 µg/24 hours. The scope of data compiled from this type of analysis can provide steroid profile information and an understanding of metabolic disturbances in steroidogenesis.
Gas Chromatography Mass Spectrometry (GC-MS)
Agilent GCMS-MSD (2000): Shimadzu GCMS-QP2020NX (2023)
Gas chromatography-mass spectrometry is a crucial asset for the discovery of novel biomarkers of endocrine conditions in patients enabling a specific “signature” for each disease to be established. GC-MS has unrivalled separation ability, permitting separation of structurally similar steroids such as α/β pairs. GC-MS is a hard ionisation technology fragmenting the steroid molecules, creating a wealth of structural information used for positive identification of steroids in biological samples.
GC-MS is utilised by SMAC in two modes;
- Targeted mode (selected ion). This allows a targeted view of steroid metabolism, including 33 steroid metabolites.
- Full Scan. This is a comprehensive analysis mode, important when the steroid(s) of importance are unknown. The data is compared to an online library containing data from hundreds of steroids and other analytes.
Steroid Extraction Methodologies
SMAC has developed and optimised several methods to extract steroids from biofluids. Our sample preparation methods aim to remove matrix contaminants and concentrate steroids. Depending on the properties of the steroid under investigation steroid extraction is optimised to provide high recovery, reproducible extraction from the biofluid.
We have the below optimised extraction methods:
- Liquid/liquid extraction (L/L)
- Solid phase extraction (SPE)
- Solid-liquid extraction (SLE)
- Tissue extraction
- Protein precipitation
- Direct analysis
- Derivatisation