Which technique is best suited for alkaline and polar analytes?

Electrospray Ionization (ESI) is particularly effective for alkaline and polar analytes due to its capability to produce ions from large biomolecules and other polar compounds efficiently. This technique ionizes samples in a solution and allows for the generation of charged droplets, which are then drawn into the mass spectrometer.

The process involves the application of a high voltage to a liquid, resulting in the formation of a fine aerosol of droplets. As these droplets evaporate, they produce gas-phase ions. Because alkaline and polar analytes often exist in a solution, ESI is advantageous as it operates in a liquid phase environment, enabling the ionization of these compounds without needing them to be turned into gas beforehand.

Furthermore, ESI is less aggressive than other ionization techniques, making it ideal for sensitive and thermally fragile compounds. This gentle ionization ensures the structural integrity of analytes, which fits perfectly for applications involving complex polar homemade standards or biomolecules. Consequently, ESI stands out as the best technique for ionizing alkaline and polar analytes.