From the food industry to pharmaceutical drug development, analytical laboratories have seen rising demand for accurate and precise measurements of analytes present in microgram and sub-microgram levels in complex study materials. While these demands are challenging, the requirement to evaluate thousands of samples at rapid times while ensuring data reliability, quality, and accuracy adds additional difficulties.
Combining liquid chromatography and mass spectrometry has given bioanalytical scientists a powerful method to overcome all stringent drug development demands. Due to their efficiency and versatility, LC-MS assays are now a desirable tool in modern analytical experiments. However, robust LC-MS method development and LC-MS method validation will remain crucial for expanding its applications in different domains of biomedical and pharmaceutical research. The current article discusses LC-MS assays provided by bioanalytical laboratories, such as ELISA testing services and LC-MS labs.
LC-MS assays for drug discovery and development
LC-MS assays are a robust technique to physically separate target compounds, followed by their detection based on their mass-to-charge ratio. LC-MS assays can selectively and accurately detect and analyze at microgram and sub-microgram levels in complex biological samples.
The liquid chromatography component physically separates analytes in study samples. Researchers inject the sample solution into the mobile phase, which is a stream of flowing solvent. This mobile phase is continuously passed through the stationary phase, which consists of a column generally filled with silica particles. Components of the mixture when reaches this stationary phase, individual analytes will interact with the column depending upon its physical or chemical properties. Hence, each analyte elutes at different times based on its interaction with the stationary phase. There are several modes of liquid chromatography, such as size exclusion chromatography, ion exchange chromatography, partition chromatography, and affinity chromatography.
Must Read: Trends Shaping the Future of Pharmacokinetics Services in Drug Development
Once the analytes in the mobile phase pass through the column, they reach a detector that captures a certain chemical or physical property of the analyte. This response is stored as chromatography peaks whose intensity corresponds to the quantity of analytes in the sample. Although this estimation is not accurate, it provides basic information about the compound mixture.
Several detectors are available for coupling with liquid chromatography, but mass spectrometers have emerged as sensitive and selective detector units. However, with mass spectrometers, the eluted components are not directly allowed to enter the mass spectrometer. As mass spectrometry operates under a vacuum, these analytes are vaporized and ionized before being allowed into the mass spectrometer units.
After entering the mass spectrometers, the ionized analytes are subjected to magnetic and electric fields where different variations in electrical/magnetic fields alter the flight paths of the analyte and ensure their separation from each other. Once these analytes are separated, they are collected and identified using different mass detectors, such as electron multipliers.
Finally, the measured analytes are analyzed by plotting a total ion chromatography. This plot compares the peak intensities of the ions against the retention times. Additionally, each chromatogram point correlates to a mass spectrum, which depicts the abundance of ions versus the measured mass to charge values.
In Conclusion
LC-MS assays are a powerful method to detect and quantify analytes in complex biological samples.