The changing impact of the collision-induced decomposition of ions on massspectrometry

The first observations of the products of the collision-induced decompositi on (CID) of ions were made in the early days of the development of mass spe ctrometry and for many years, they were regarded as little more than a nuis ance. Early in the 1960s, systematic work on CID began, and, although it pr oved to be very useful in the investigation of the structures of ions, in g eneral, the mass spectrometry community regarded CID as a subject for funda mental studies but of little value in analytical work. In essence, CID was a technique looking for a problem. With the advent of soft ionisation metho ds, first fast atom bombardment and later electrospray ionisation and matri x-assisted laser desorption ionisation, all of which gave molecular weight information but no structural information, the situation changed, and CID b ecame an integral part of analytical mass spectrometry. High-performance, c ompact tandem mass spectrometers based on the quadrupole, time-of-flight an d ion trap mass analysers play an increasingly important role in biological mass spectrometry and Fourier transform ion cyclotron resonance instrument s provide very-high-resolution CID capabilities. Tandem mass spectrometry i s already the method of choice for the sequencing of proteins and will undo ubtedly be important in helping us understand protein function. (C) 2000 El sevier Science B.V.