Massispektromeetrias

Massispektromeetrias, commonly referred to as mass spectrometry, is an analytical technique that measures the mass-to-charge ratio of ionized molecules to determine their masses and identities. It is used to identify compounds, determine structural information, and quantify substances in complex mixtures. The method is versatile for small organic molecules, biomolecules such as peptides and proteins, lipids, metabolites, and environmental or forensic samples.

The general principle involves ionizing sample molecules to produce charged species, separating these ions according to their mass-to-charge ratios in a mass analyzer, and detecting the ions to generate a mass spectrum. The spectrum shows how abundant each ion is at each m/z value, providing a molecular signature that can be used for identification and quantitation. Modern instruments often combine high sensitivity with high mass accuracy and resolution.

Common ionization approaches include electron ionization (EI) for small, volatile molecules; electrospray ionization (ESI) for larger, labile biomolecules; and matrix-assisted laser desorption/ionization (MALDI) for peptides, proteins and polymers. Mass analyzers such as quadrupole, time-of-flight (TOF), orbitrap, and Fourier-transform ion cyclotron resonance (FT-ICR) offer varying balances of speed, resolution, and mass accuracy. Tandem mass spectrometry (MS/MS) further fragments selected ions to provide detailed structural information.

Applications span proteomics, metabolomics, pharmaceutical analysis, environmental monitoring, food safety, and clinical diagnostics. Limitations include ionization biases, matrix effects, and the need for appropriate standards and data analysis tools. Continuous advances enhance sensitivity, resolution, and the ability to analyze increasingly complex samples.