Studying the urinary proteome is now one of the most promising topics in disease biomarker discovery. Mass spectrometer-based bioanalytical methods are now at the forefront of proteomic analysis. Besides, they are continuously emerging as a vital tool in clinical bioanalysis. Despite such technological advances, very few biomarkers have entered clinical settings. This lack of initiation is due to the complexities and challenges surrounding biomarker discovery and assay validation. Specifically, complexity in urinalysis and the presence of endogenous proteins are prominent factors affecting biomarker discovery and analysis in the urinary proteome.
Over the years, LC-MS systems have evolved as a gold standard for detecting and measuring individual steroids. However, when it comes to identifying novel metabolomes, GC-MS systems are still the industry leaders. Even though they lack high-sensitivity analysis, GC-MS is still the most powerful tool for discovering novel steroid metabolomes, especially in urinary proteomes. Hence, the current article highlights the critical benefits of GC-MS so that bioanalytical labs such as NorthEast bioanalytical laboratories can make full use of these robust systems. Following are the top five benefits of using GC-MS in biomarker analysis and discovery through urinary proteome.
Assess metabolites of steroid hormones
GC-MS systems can readily assess the metabolites of steroid hormones. Moreover, they can also analyze precursors of these metabolites. GC-MS systems can run either through the comprehensive mode or the targeted mode. A comprehensive or scanned mode can efficiently run all the steroids in a single GC-MS run. Besides, data for each steroid can be easily retrieved even after several years. Moreover, urine steroid analysis was first conducted through GC analysis, and even after 70 years, almost all steroid hormone disorders are characterized by GC-MS analysis.
Better chromatographic resolution
Compared to LC-MS and LC-MS/MS systems, GC-MS offers a better chromatographic resolution. With the advent of small particle-sized packings, LC-MS systems have greatly improved in recent years. However, they still lack behind due to longer run times. GC-MS systems rely on derivatizing the steroid molecules through methyloxime-trimethylsilyl ether formation. This derivatization is labor intensive, but it readily characterizes the molecular structures through the C-O and C-OH groups. MS fragmentation usually depends on derivatization. Besides, abundant literature is available on the generation of ions through GC-MS analysis. Hence, it is easier to place functional groups in the molecular structure.
Specifically, GC-MS systems are robust technologies for separating epimeric steroids. This feature makes GC-MS systems the primary technique for characterizing metabolic disorders such as 5α-reductase type 2 deficiency, 17β-hydroxysteroid dehydrogenase type 3 deficiency, apparent cortisone reductase deficiency, and apparent mineralocorticoid excess deficiency.
Robust tool for discovery studies
The scan mode in GC-MS analysis allows non-targeted profiling of steroid hormones. Besides, the scan mode helps discover novel compounds, pathways, and metabolomes. Researchers can store the scanned data for an indefinite period. These features make the GC-MS technique a robust discovery tool.
Integrating GC systems with tandem mass spectrometers
Although single-stage mass spectrometers are sufficient for identifying steroids, GC-integrated mass spectrometers provide additional accuracy in steroid analysis. The GC-MS/MS ion-trap instrument is particularly beneficial when measuring small amounts of target analytes in high background disturbances.