Ion-attachment mass spectrometry (IAMS) is a form of 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...

 that uses a "soft" form of ionization similar to chemical ionization

Chemical ionization

Chemical ionization is an ionization technique used in mass spectrometry. Chemical ionization is a lower energy process than electron ionization. The lower energy yields less fragmentation, and usually a simpler spectrum...

 in which a cation is attached to the analyte molecule in a reactive collision:

Where M is the analyte molecule, X⁺ is the cation and A is a non-reacting collision partner.

Principle

This technique is applicable to gases or any materials that can be vaporized. It uses a non-fragmenting non-conventional ionisation mode, by attachment of a lithium (or alkaline) ion to the gas to be analysed with a more traditional mass filter. This instrument is more dedicated to analysis of moderately-sized molecules such as organic or aromatic compounds.

Applications

Currently, it is used industrially to verify, with a high throughput, the concentrations of brominated flame retardants (BFR) in plastics in compliance with European

European Union

The European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...

 RoHS (Restriction of Hazardous Substances) regulation in place since 2006. The banned molecules include PBB

Polybrominated biphenyl

Polybrominated biphenyls , also called brominated biphenyls or polybromobiphenyls, are a group of manufactured chemicals, of the polyhalogenated compounds. Their chlorine analogs are the PCBs...

 and PBDE

PBDE

Polybrominated diphenyl ethers or PBDE, are organobromine compounds that are used as flame retardants. Like other brominated flame retardants, PBDEs have been used in a wide array of products, including building materials, electronics, furnishings, motor vehicles, airplanes, plastics,...

, whose concentration should not exceed 0.1% w/w.

IAMS has also been used to analyze diesel exhaust particles, in ceramic processing and in critical SiO₂ etching during semiconductor manufacturing.

External links

• RoHS official text Ion Attachment Mass Spectrometry Method. Ion Attachment Mass Spectrometry Apparatus