MS (LC–MS/MS, HRMS, IMS)
Mass spectrometry (MS) refers to the analysis of proteins by ionization of the species and measurement of the mass-to-charge ratio of the ions, enabling the identification of molecules in pure samples and complex mixtures.
Liquid chromatography–tandem mass spectrometry (LC–MS/MS) combines liquid chromatography for separating compounds with tandem mass spectrometry for identifying and quantifying them, offering high sensitivity and precision in complex sample analysis. Tandem mass spectrometry employs two analytical stages, typically separated in space (e.g., triple quadrupole or quadrupole-time of flight) or separated in time (e.g., 3D ion trap).
High-resolution mass spectrometry (HRMS) HRMS is capable of accurate measurement of the molecular weight of a compound via their mass-to-charge ratio (m/z). HRMS is generally referred to having a mass spectral resolving power >10,000 where resolution is m/δm (with m being mass and δm the smallest mass difference for which the two peaks m and [m+δm] are resolved.
Ion-mobility spectrometry (IMS) is a technique used in conjunction with mass spectrometry to separate ions based on relative mobilities in a drift cell with electric field and carrier buffer gas. The mobility of an ion depends on cross-sectional area, shape and charge.