Ionisaatiomenetelmät

Ionisaatiomenetelmät refer to a range of techniques used to create ions. Ions are atoms or molecules that have gained or lost one or more electrons, resulting in a net electrical charge. These methods are fundamental in various scientific fields, including mass spectrometry, analytical chemistry, and plasma physics.

One common method is electron ionization (EI), where a beam of high-energy electrons bombards neutral atoms or molecules. The collision transfers sufficient energy to dislodge an electron, forming a positively charged ion. Another widely used technique is chemical ionization (CI). In CI, a reagent gas is first ionized, and these reagent ions then react with the analyte molecules to produce ions, often through proton transfer. This method is generally gentler than EI, leading to less fragmentation of the analyte.

Electrospray ionization (ESI) is a soft ionization technique particularly suited for large and polar molecules like proteins and peptides. In ESI, a solution of the analyte is sprayed through a charged capillary at high voltage. The resulting charged droplets evaporate, shrinking until the analyte molecules are ejected as ions. Matrix-assisted laser desorption/ionization (MALDI) is another soft ionization method, often used for biomolecules. The analyte is mixed with a matrix compound that absorbs laser energy. Upon laser irradiation, the matrix vaporizes, carrying the analyte molecules into the gas phase as ions. These varied methods allow for the ionization of a wide range of substances under different conditions, enabling detailed analysis and study.