Mass Spectra
Mass Spectra - Related Videos
02:39
Emission Spectra
0 Views •
2020
When solids, liquids, or condensed gases are heated sufficiently, they radiate some of the excess energy as light. Photons produced in this manner have a range of energies, and thereby produce a continuous spectrum in which an unbroken series of wavelengths is present. In contrast to continuous spectra, light can also occur as discrete or line spectra having very narrow linewidths interspersed throughout the spectral regions. Exciting a gas at low partial pressure using an electrical current,...
07:09
Tandem Mass Spectrometry
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2023
In tandem mass spectrometry a biomolecule of interest is isolated from a biological sample, and then fragmented into multiple subunits in order to help elucidate its composition and sequence. This is accomplished by having mass spectrometers in series. The first spectrometer ionizes a sample and filter ions of a specific mass to charge ratio. Filtered ions are then fragmented and passed to a second mass spectrometer where the fragments are analyzed. This video introduces the principles of...
07:27
MALDI-TOF Mass Spectrometry
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2023
Matrix-assisted laser desorption ionization (MALDI) is a mass spectrometry ion source ideal for the analysis of biomolecules. Instead of ionizing compounds in the gaseous state, samples are embedded in a matrix, which is struck by a laser. The matrix absorbs the majority of the energy; some of this energy is then transferred to the sample, which ionizes as a result. Sample ions can then be identified using a time-of-flight analyzer (TOF). This video covers principles of MALDI-TOF, including...
15:35
Analyzing Large Protein Complexes by Structural Mass Spectrometry
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Cited by 68 •
2010
Mass spectrometry has proven to be a valuable tool for analyzing large protein complexes. This method enables insights into the composition, stoichiometry and overall architecture of multi-subunit assemblies. Here, we describe, step-by-step, how to perform a structural mass spectrometry analysis, and characterize macromolecular structures.
06:28
Flow Virometry to Analyze Antigenic Spectra of Virions and Extracellular Vesicles
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Cited by 9 •
2017
Viruses or extracellular vesicles were immunocaptured with 15 nm magnetic nanoparticles coupled to antibodies recognizing surface antigens. The captured virions or vesicles were labeled with fluorescent antibodies against other surface antigens. The resultant complexes were separated in high magnetic field and analyzed with conventional flow cytometers triggered on fluorescence.
FAQs
Each peak is positioned according to an ion’s mass-to-charge ratio, while its relative abundance indicates how prominently that ion was detected compared with others. Examining peak positions helps chemists assess molecular mass and distinguish ions formed from the same sample. Together, the distribution of positions and intensities provides evidence for chemical identification and mixture analysis.
Isotope patterns provide additional evidence for determining molecular formulas and recognizing the composition of ions. Related peaks arising from isotopic forms can accompany a molecular ion or fragment, creating a characteristic distribution rather than a single isolated signal. Chemists compare this pattern with other spectral features to strengthen compound identification and molecular-mass assignments.
Fragmented ions preserve structural information even when the original molecule produces more than one detectable species. Their characteristic mass-to-charge ratios can support identification of a compound and help distinguish substances with similar molecular masses. Evaluating the fragments alongside the molecular mass and isotope pattern makes structural elucidation more informative than relying on one peak alone.
The sample is first introduced into a mass spectrometer, where its molecules are ionized. Ionization may also produce fragments. The resulting ions are then separated according to their mass-to-charge ratios and detected, generating peaks with corresponding relative abundances. Chemists interpret these data by considering molecular mass, isotope patterns, and characteristic fragment ions.
Identification combines several observations rather than depending on a single signal. Chemists examine the apparent molecular mass, isotope pattern, and characteristic fragments, then assess whether these features support a particular molecular formula or compound identity. This approach is useful for confirming substances, characterizing reaction products, and interpreting components within a more complex sample.
Chromatography is combined with mass spectrometry when a sample contains multiple components that require analysis. The combined approach supports trace analysis, mixture characterization, environmental monitoring, pharmaceutical research, and the study of biological molecules. Mass spectral information then helps identify or characterize separated components through their molecular masses, isotope patterns, and diagnostic fragments.