Liquid chromatography-mass spectrometry (LC-MS) assays are increasingly becoming the preferred separation tool in bioanalysis. LC-MS testing is a robust technique that combines the resolving power of HPLC with the detection specificity of MS units. The liquid chromatography component separates samples based on their affinities to the stationary phase, while the MS unit detects ions based on the mass-to-charge ratio. Hence LC-MS laboratories employ this technique to generate information about the structure, identity, weight, and quantity of the analytes of interest. The current article dives deep into LC-MS testing to unravel its hidden power for generating accurate and reliable results.
Why are LC-MS services cutting-edge technology?
Numerous factors in LC-MS testing make this method so reliable and robust. Let us understand different aspects of LC-MS testing.
LC-MS systems can examine samples that were difficult to investigate earlier. It significantly expands the use of this system to analyze a large range of organic compounds. The study samples can range from large proteins to small pharmaceutical compounds. Besides, compared to gas chromatography-mass spectrometers, LC-MS assays can analyze polar, ionic, non-volatile, large, and thermally unstable compounds.
LC-MS systems are highly selective. It can detect specific compounds present at trace levels in complex study material. Besides, they are highly sensitive and can detect specific masses that have characteristics of the compound of interest. Additionally, the selectivity and sensitivity of LC-MS systems can be enhanced significantly by using other combinations of detectors, such as combining mass spectrometers with UV detectors.
The interface is the most crucial aspect of LC-MS assays that joins LC and MS units. LC requires high pressure and also produces a higher gas load. On the other hand, mass spectrometers work in a vacuum with limited gas load. Not to mention liquid chromatography requires near ambient temperature, whereas mass spectrometers work at elevated temperatures. Hence reliable interface is crucial for the working of LC-MS systems. Today there are several techniques for converting analytes into ions, including atmospheric pressure ionization, API-electrospray, and atmospheric pressure chemical ionization. Each of these techniques has its unique advantages.
Moreover, mass spectrometers work in two modes, scan, and selected ion monitoring mode. This mode can analyze different analytes over an extensive mass range. Hence, it is beneficial in identifying different ions. On the other hand, the selected ion monitoring mode can effectively detect and quantify these ions based on their mass-to-charge ratios.
LC-MS systems have numerous applications ranging from pharmaceutical studies to environmental analysis. LC-MS systems are used extensively to determine the molecular weights of analytes during drug development studies. They can differentiate similar octapeptides and determine the molecular weight of different proteins. Today combinatorial chemistry has upgraded the entire drug discovery process. Instead of manual protocols, researchers employ robotics for loading samples into LC-MS systems, providing high throughput and automated LC-MS units.
Not to mention food applications such as identifying toxic metabolites in food products and environmental applications of detecting phenyl urea herbicides and carbamates have further skyrocketed the applications of LC-MS systems in numerous scientific disciplines. However, the reliability of LC-MS systems will always depend on a robust method development and validation initiative for demonstrating the reliability of LC-MS assays.