Fast atom bombardment is an ionization

Ionization

Ionization is the process of converting an atom or molecule into an ion by adding or removing charged particles such as electrons or other ions. This is often confused with dissociation. A substance may dissociate without necessarily producing ions. As an example, the molecules of table sugar...

 technique used in mass spectrometry

Mass spectrometry

Mass spectrometry is an analytical technique that measures the mass-to-charge ratio of charged particles.It is used for determining masses of particles, for determining the elemental composition of a sample or molecule, and for elucidating the chemical structures of molecules, such as peptides and...

. The material to be analyzed is mixed with a non-volatile chemical protection environment called a matrix

Matrix Isolation

Matrix isolation is an experimental technique used in chemistry and physics which generally involves a material being trapped within an unreactive matrix. A host matrix is a continuous solid phase in which guest particles are embedded. The guest is said to be isolated within the host matrix...

 and is bombarded under vacuum with a high energy (4000 to 10,000 electron volts) beam of atoms. The atoms are typically from an inert gas such as argon

Argon

Argon is a chemical element represented by the symbol Ar. Argon has atomic number 18 and is the third element in group 18 of the periodic table . Argon is the third most common gas in the Earth's atmosphere, at 0.93%, making it more common than carbon dioxide...

 or xenon

Xenon

Xenon is a chemical element with the symbol Xe and atomic number 54. The element name is pronounced or . A colorless, heavy, odorless noble gas, xenon occurs in the Earth's atmosphere in trace amounts...

. Common matrices include glycerol

Glycerol

Glycerol is a simple polyol compound. It is a colorless, odorless, viscous liquid that is widely used in pharmaceutical formulations. Glycerol has three hydroxyl groups that are responsible for its solubility in water and its hygroscopic nature. The glycerol backbone is central to all lipids...

, thioglycerol, 3-nitrobenzyl alcohol

3-Nitrobenzyl alcohol

The compound 3-nitrobenzyl alcohol is an organic compound with the formula C7H7NO3.-Desorption mass spectrometry matrix:In mass spectrometry this compound is often abbreviated as "3-NBA" or "m-NBA." It has been used as a liquid matrix for fast atom bombardment and matrix-assisted laser desorption...

 (3-NBA), 18-Crown-6

18-Crown-6

18-Crown-6 is an organic compound with the formula [C2H4O]6 and the IUPAC name of 1,4,7,10,13,16-hexaoxacyclooctadecane. The compound is a crown ether. Crown ethers coordinate some metal cations in their central cavity; 18-crown-6 displays a particular affinity for potassium cations. The synthesis...

 ether, 2-nitrophenyloctyl ether, sulfolane

Sulfolane

Sulfolane is a clear, colorless liquid commonly used in the chemical industry as an extractive distillation solvent or reaction solvent. Sulfolane was originally developed by the Shell Oil Company in the 1960s as a solvent to purify butadiene...

, diethanolamine, and triethanolamine

Triethanolamine

Triethanolamine, often abbreviated as TEA, is an organic chemical compound which is both a tertiary amine and a triol. A triol is a molecule with three alcohol groups. Like other amines, triethanolamine is a strong base due to the lone pair of electrons on the nitrogen atom. Triethanolamine can...

. This technique is similar to secondary ion mass spectrometry

Secondary ion mass spectrometry

Secondary ion mass spectrometry is a technique used in materials science and surface science to analyze the composition of solid surfaces and thin films by sputtering the surface of the specimen with a focused primary ion beam and collecting and analyzing ejected secondary ions...

 and plasma desorption mass spectrometry

Plasma desorption mass spectrometry

Plasma desorption ionization mass spectrometry is a mass spectrometry technique in which ionization of material in a solid sample by bombarding it with ionic or neutral atoms formed as a result of the nuclear fission of a suitable nuclide, typically the Californium isotope 252Cf.-See also:* Fast...

.

How it works

FAB is a relatively soft ionization technique and produces primarily intact protonated molecules denoted as [M+H]⁺ and deprotonated molecules such as [M-H]^-. The nature of its ionization products places it close to electrospray

Electrospray

The name electrospray is used for a device that employs electricity to disperse a liquid or for the fine aerosol resulted in this process. The method is sometimes improperly called electrohydrodynamic atomization. High voltage is applied to a liquid supplied through an emitter...

 and MALDI.

The first example of the practical application of this technique was the elucidation of the amino acid sequence of the oligopeptide efrapeptin D. This contained a variety of very unusual amino acid residues. The sequence was shown to be: N-acetyl-L-pip-AIB-L-pip-AIB-AIB-L-leu-beta-ala-gly-AIB-AIB-L-pip-AIB-gly-L-leu-L-iva-AIB-X. PIP = pipecolic acid

Pipecolic acid

Pipecolic acid is a small organic molecule which accumulates in pipecolic acidemia. It is the carboxylic acid of piperidine.It can be associated with some forms of epilepsy....

, AIB = alpha-amino-isobutyric acid, leu = leucine

Leucine

Leucine is a branched-chain α-amino acid with the chemical formula HO2CCHCH2CH2. Leucine is classified as a hydrophobic amino acid due to its aliphatic isobutyl side chain. It is encoded by six codons and is a major component of the subunits in ferritin, astacin and other 'buffer' proteins...

, iva = isovaline

Isovaline

Isovaline is a rare amino acid that was found in the Murchison meteorite. It is an isomer of the biologically important amino acid valine. It may have analgesic properties....

, gly = glycine

Glycine

Glycine is an organic compound with the formula NH2CH2COOH. Having a hydrogen substituent as its 'side chain', glycine is the smallest of the 20 amino acids commonly found in proteins. Its codons are GGU, GGC, GGA, GGG cf. the genetic code.Glycine is a colourless, sweet-tasting crystalline solid...

. This is a potent inhibitor of the mitochodrial ATPase activity.