Massaspectrometrie

Massaspectrometrie (mass spectrometry) is an analytical technique used to measure the mass-to-charge ratio of ions, enabling the identification and quantification of chemical species. In a typical workflow, a sample is ionized to produce charged species, which are then separated by a mass analyzer and detected to produce a mass spectrum. Ionization methods vary with the sample; common approaches include electron ionization for small, volatile molecules, electrospray ionization for large biomolecules, and matrix-assisted laser desorption/ionization for polymers and proteins.

Mass analyzers separate ions according to their m/z. Examples include quadrupole filters, ion traps, time-of-flight (TOF), Orbitrap, and FT-ICR. Some instruments perform multiple stages of analysis (MS/MS or tandem MS) to obtain fragmentation data that aids in structural elucidation. High-resolution mass spectrometry can determine accurate masses, facilitating molecular formula assignments, while quantitative measurements are achieved with calibrated standards and appropriate data processing.

Data interpretation involves examining peak patterns, isotope distributions, and, in many cases, fragment ions produced during MS/MS. Instrument performance depends on sensitivity, mass accuracy, resolution, and dynamic range, as well as sample preparation and ionization efficiency. Calibration and appropriate controls are essential for reliable results.

Applications of massaspectrometrie are widespread, including proteomics, metabolomics, pharmacokinetics, environmental analysis, and materials science. The technique provides both qualitative information (identity, structure) and quantitative data (concentration) across diverse sample types, making it a central tool in modern analytical chemistry.