massaspektrometria

Massaspektrometria, also called mass spectrometry, is an analytical technique used to determine the masses of molecules and to infer their chemical structures. The method involves converting samples into gas-phase ions, separating these ions according to their mass-to-charge ratio (m/z) in a mass analyzer, and detecting the ions to generate a mass spectrum. The spectrum provides information on molecular weight, isotopic composition, and, in many cases, fragmentation patterns that aid structural elucidation.

Ionization methods include electron ionization (EI) for volatile compounds, electrospray ionization (ESI) suitable for biomolecules, matrix-assisted laser desorption/ionization (MALDI) for large molecules, and various atmospheric pressure techniques. Coupling with chromatography, such as liquid chromatography (LC-MS) or gas chromatography (GC-MS), helps separate complex mixtures before ionization and analysis.

Common mass analyzers include quadrupole, time-of-flight (TOF), Orbitrap, and Fourier transform ion cyclotron resonance (FT-ICR); tandem MS (MS/MS) uses selected ions fragmented in collision cells to obtain structural information and enhance specificity. High-resolution MS provides accurate mass measurements that assist in formula determination.

Applications span proteomics, metabolomics, pharmaceutical analysis, environmental monitoring, food safety, and clinical diagnostics. Quantitative analyses frequently employ internal standards and calibration curves; sensitivity can reach parts-per-trillion in specialized configurations, with wide dynamic range.

Limitations include matrix effects and ion suppression, isomeric species that share the same nominal mass, and the need for standards for precise quantification. Ongoing developments aim to improve resolution, speed, sensitivity, and robustness, enabling more routine use in research and clinical settings.