Mass spectrometry (not "mass spectrography") is a powerful analytical technique used to identify and quantify chemical compounds based on their mass-to-charge ratio. It is widely used in various scientific fields, including chemistry, biochemistry, pharmacology, environmental analysis, and forensic science.
The basic principle of mass spectrometry involves the ionization of molecules, followed by their separation and detection based on their mass-to-charge ratio (m/z). Here is a simplified overview of how mass spectrometry works:
Ionization: The sample is first ionized to convert the molecules into charged particles or ions. Various ionization methods can be employed, such as electron ionization (EI), electrospray ionization (ESI), or matrix-assisted laser desorption/ionization (MALDI). The choice of ionization method depends on the nature of the sample.
Mass separation: The ions generated from the sample are then introduced into the mass spectrometer. Inside the instrument, the ions are subjected to an electric or magnetic field, which causes their deflection based on their mass-to-charge ratio. Lighter ions experience greater deflection than heavier ions.
Detection: The separated ions are detected by a detector, which generates a signal proportional to the abundance of each ion. This signal is then converted into a mass spectrum, which is a graphical representation of the ion abundances as a function of their mass-to-charge ratio.
Data analysis: The mass spectrum obtained from the detector provides valuable information about the sample. By comparing the mass spectrum to databases or using various data analysis techniques, scientists can identify the compounds present in the sample and determine their relative quantities.
Mass spectrometry can provide information not only about the molecular mass of compounds but also about their structure, fragmentation patterns, isotopic composition, and even their interactions with other molecules. It is a versatile tool used for a wide range of applications, including drug discovery, proteomics, metabolomics, environmental analysis, and forensic investigations.