Electron capture dissociation

Electron capture dissociation

In mass spectrometry, electron capture dissociation (ECD) is a method of fragmenting gas phase ions for tandem mass spectrometric analysis (structural elucidation). ECD involves the direct introduction of low energy electrons to trapped gas phase ions. [Zubarev, R. A.; Kelleher, N. L.; McLafferty, F. W. Electron Capture Dissociation of Multiply Charged Protein Cations - a Nonergodic Process "J. Am. Chem. Soc." 1998, "120", 3265-3266.]

Principles

Electron capture dissociation typically involves a multiply protonated molecule "M" interacting with a free electron to form an odd-electron ion

: [M + nH] ^{n+} + e^- o igg [ [M + nH] ^{(n-1)+} igg] ^* o fragments.

Liberation of the electric potential energy results in fragmentation of the product ion.

ECD produces significantly different types of fragment ions than other fragmentation methods such as collision-induced dissociation and infrared multiphoton dissociation. These other methods introduce internal vibrational energy in some way or another while ECD does not. The unique (and complementary) fragments observed and the ability to fragment whole macromolecules effectively has been promising. The low efficiencies and other experimental difficulties have prevented wide spread use. ECD is primarily used in Fourier transform ion cyclotron resonance mass spectrometry.cite journal |author=Cooper HJ, Håkansson K, Marshall AG |title=The role of electron capture dissociation in biomolecular analysis |journal=Mass spectrometry reviews |volume=24 |issue=2 |pages=201–22 |year=2005 |pmid=15389856 |doi=10.1002/mas.20014]

ECD is a recently introduced technique and is still being investigated. [cite journal |author=Syrstad EA, Turecek F |title=Toward a general mechanism of electron capture dissociation |journal=J. Am. Soc. Mass Spectrom. |volume=16 |issue=2 |pages=208–24 |year=2005 |pmid=15694771 |doi=10.1016/j.jasms.2004.11.001] [cite journal |author=Savitski MM, Kjeldsen F, Nielsen ML, Zubarev RA |title=Complementary sequence preferences of electron-capture dissociation and vibrational excitation in fragmentation of polypeptide polycations |journal=Angew. Chem. Int. Ed. Engl. |volume=45 |issue=32 |pages=5301–3 |year=2006 |pmid=16847865 |doi=10.1002/anie.200601240] The mechanism of ECD is still under debate but appears not to necessarily break the weakest bond and is therefore thought to be a fast process (nonergodic) where energy is not free to relax intramolecularly. Suggestions have been made that radical reactions initiated by the electron may be responsible for the action of ECD.Fact|date=October 2007

In a similar technique called electron transfer dissociation the electrons are transferred by collision between the analyte cations and anions.

ee also

*RRKM theory

External links

* [http://www.ionspec.com/FTMS%20Tutorial/FTMS%20Tutorial%20Pt%204/tutorial%20pt4_info.htm A tutorial on tandem FTMS including ECD]

References


Wikimedia Foundation. 2010.

Игры ⚽ Поможем сделать НИР

Look at other dictionaries:

  • Electron Capture Dissociation — (ECD) ist eine Methode zur Fragmentierung von Ionen in der Tandem Massenspektrometrie. Dabei werden durch eine Emitterkathode Elektronen mit niedriger Energie erzeugt. Diese werden von mehrfach protonierten Molekülen in der Gasphase eingefangen,… …   Deutsch Wikipedia

  • Electron transfer dissociation — (ETD) is a method to fragment ions in a mass spectrometer.cite journal |author=Syka JE, Coon JJ, Schroeder MJ, Shabanowitz J, Hunt DF |title=Peptide and protein sequence analysis by electron transfer dissociation mass spectrometry |journal=Proc.… …   Wikipedia

  • Negative electron-transfer dissociation — (NETD) is an ion/ion reaction in which an electron from an anionic specie is transferred to cationic reagent.[1] Following this transfer event, the electron deficient anion undergoes internal rearrangement and fragments. NETD is the ion/ion… …   Wikipedia

  • Infrared multiphoton dissociation — Infobox chemical analysis name = Infrared multiphoton dissociation caption = acronym = IRMPD classification = analytes = manufacturers = related = Blackbody infrared radiative dissociation Electron capture dissociation Collision induced… …   Wikipedia

  • Blackbody infrared radiative dissociation — Infobox chemical analysis name = Blackbody infrared radiative dissociation caption = acronym = BIRD classification =Mass spectrometry analytes = manufacturers = related = Infrared multiphoton dissociation Collision induced dissociation Electron… …   Wikipedia

  • Tandem mass spectrometry — Tandem mass spectrometry, also known as MS/MS, involves multiple steps of mass spectrometry selection, with some form of fragmentation occurring in between the stages. [IUPAC gold book definition of tandem mass spectrometer… …   Wikipedia

  • Mass spectrometry — (MS) is an analytical technique that measures the mass to charge ratio of charged particles.[1] It is used for determining masses of particles, for determining the elemental composition of a sample or molecule, and for elucidating the chemical… …   Wikipedia

  • Fragmentation (chemistry) — Fragmentation is a type of chemical dissociation. Fragmentation of a molecule can take place by a process of heterolysis or homolysis. It is a phenomenon observed in mass spectrometry where it is used as a tool to find the structural formula of a …   Wikipedia

  • Fred McLafferty — Infobox Scientist image width = 150px name = Fred W. McLafferty birth date = birth date and age|1923|5|11 birth place = Evanston, Illinois residence = United States nationality = United States field = Chemist work institutions = Purdue University …   Wikipedia

  • Neil Kelleher (scientist) — Neil L. Kelleher Residence United States Nationality United States Fields …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”