Electrospray ionization mass spectrometry (ESI-MS) is a highly sensitive and versatile analytical technique used to determine the molecular mass and structural information of a wide range of molecules. This technique is particularly effective in the study of biomolecules, such as proteins, peptides, nucleic acids, carbohydrates, and lipids.
In ESI-MS, a sample solution containing the analyte of interest is introduced into an ionization chamber, where it is nebulized into a fine aerosol of charged droplets. The nebulization process is facilitated by applying a high voltage to the solution, causing the solvent molecules to evaporate and leaving behind multiply charged analyte ions in the gas phase.
The charged droplets then pass through a capillary tube or needle, which is maintained at high voltage, leading to further desolvation and evaporation of solvent molecules. As the droplets shrink in size, the charge becomes concentrated on the analyte molecules, resulting in the formation of gas-phase ions.
These ions are then introduced into the mass spectrometer, where they are separated based on their mass-to-charge ratio (m/z) and detected by their respective signals. The resulting mass spectrum provides valuable information about the molecular weight, charge state, and fragmentation patterns of the analyte.
ESI-MS offers high sensitivity and selectivity, allowing for the detection of trace amounts of analytes in complex mixtures. It is widely used in various fields, including drug discovery, proteomics, metabolomics, environmental analysis, and forensic science, due to its ability to provide detailed structural information about the analyzed molecules.
