Right from the early 20^th century, mass spectrometry has been used for a wide variety of applications ranging from estimating the masses of elements and their isotopes to small molecule identification and characterization to modern day proteomics analysis. According to the time period and the need, mass spectrometry and mass spectrometers have evolved. Various types of mass spectrometers exist today to address a diverse set of application areas ranging from detecting chemical agents for defense purposes at the war front to structural characterization of the most complex of proteins for drug research.

Mass spectrometry involves three basic steps: first the generation of ions, second the separation of ions and third the detection of ions. Different mass spectrometers achieve this in different ways to address different needs. The following is a brief introduction to the LCQ technology that has been pioneered by Thermo Fisher Scientific over the years. There are four basic steps: Make, Move, Select and Detect for mass spectrometry using the Thermo Scientific LCQ. The ions are first made either in solution phase (using the ESI) or at the probe (using the APCI). These ions are moved to the ion trap without contact with the internal parts of the instrument which would otherwise neutralize the ion and lose it in the analysis. This is achieved by a series of ion optics that use a combination of DC voltage, RF voltage and a vacuum gradient. The selection of ions and the scan event dynamics are completed within the ion trap itself. Only the selected ions leave the ion trap to be detected. These may be either a selected group of m/z ions or a single m/z ion in their original form or fragments thereof, depending on the selected scan events. Detection of the ions is then completed by a combination of the conversion dynode and photomultiplier. For a detailed description of the LCQ technology, please refer to the tutorial LCQ for Biotech .

The influence of mass spectrometry in proteomics can not be less emphasized. Mass spectrometry in proteomics today addresses three broad application areas, identification of individual proteins from a mixture, quantification of proteins in a cell or organism and characterization of proteins to better explain its characteristics. Identification of all the proteins in a cell or organism is often a daunting task and poses a challenge even in the case of simple bacteria. Tandem mass spectrometry is currently used for protein identification studies. Ion trap mass spectrometers generate high quality data and represent the state-of-the-art in protein identification research. Protein quantification studies are important because there is often very little correlation between gene and protein expression. Characterization of proteins is very important in that it helps define the specific functionality of the protein. These days extensive characterization studies are being carried out with the aid of mass spectrometers, to characterize proteins at all levels, starting from their primary structure through studying protein-protein interactions.

Thermo Fisher Scientific realizes the need for the extensive use of mass spectrometers in proteomics and hence provides the research community a wide array of mass spectrometers. A market leader in Ion Trap technology, Thermo Fisher Scientific has continuously strived to provide the best and latest in mass spectrometry technology heralding proteomics research in the new millennium. For a list of product offerings please visit our proteomics featured products page.