Journal of Proteomics & Bioinformatics
Open Access

Application and Working Process of Tandem Mass Spectrometry

Lucimar Fialho^{* *}Correspondence: Lucimar Fialho, Department of Applied Instrumental Analysis, Federal University of Sao Carlos, Sao Carlos, Brazil, Email:

Author info »

Description

Tandem Mass Spectrometry (TEM), also known as MS/MS or MS², is an instrumental and analytical technique that combines two or more mass spectrometers using an additional reaction step to increase the ability to analyze chemical samples. Principles of Tandem Mass Spectrometry are based on the coupling of sequential mass spectrometers to analyze complex mixtures. The basic application of tandem MS is its very high specificity. TEM signal and noise ratio is better than normal MS despite the fact that there is low signal at the time. Mass spectrometry/mass spectrometry (MS/MS) or tandem mass spectrometry is a method to improve the specificity of a mass spectrometer. The entire proteome is enzymatically breaked, chromatographically separated and investigated using tandem mass spectrometry. The TEM process aims to generate a collection of peptide fragment ions that differ in mass by a single amino acid, allowing the amino acid sequence of the precursor peptide to be discovered properly. Two mass spectrometers connected by a collision cell are called MS/MS or tandem MS. Tandem mass spectrometry (MS/MS) is an important advance in neonatal screening for inherited metabolic disorders. MS/MS is faster, more sensitive, more specific, and more reliable than traditional methods for analyzing dried blood samples. It works by separating ions of different mass-to-charge ratios (m/z) to create spectra, where m is the molecular or atomic mass and z is the unit electrostatic charge. In many cases (such as small molecules) z=1, measured as m/z=mass of fragment. Tandem mass spectrometry includes triple Quadrupole (QqQ) mass spectrometers, multisector mass spectrometers, Quadrupole Time-of-Flight (Q-TOF) and hybrid mass spectrometers. A triple quadrupole mass spectrometer uses the first and his third quadrupoles as mass filters. As the analyte passes through his second quadrupole, collisions with the gas cause fragmentation. The Q-TOF mass spectrometer is a combination of TOF and quadrupole instruments that provide high mass accuracy of product ions, precise quantification capabilities, and applicability for fragmentation experiments. This is a mass spectrometry method that determines the ion fragmentation ratio (m/z) by time-of-flight measurements. A hybrid mass spectrometer consists of two or more mass spectrometers. Tandem mass spectrometry involves two independent phases of mass spectrometry to elucidate relationships between ions in a mass spectrum or to identify compounds in complex mixtures that have not been previously separated. TEM uses two mass filters placed in series with a collision cell in between. This involves multiple steps of mass spectrometry selection, with some form of fragmentation occurring between steps. In a tandem mass spectrometer, ions are formed in the ion source and separated according to their mass-to-charge ratio in the first stage of mass analysis (MS¹). Ions with specific mass-to-charge ratios (precursor ions) are selected, and fragment ions (product ions) are produced by collision-induced dissociation, ion-molecule reactions, photo dissociation, or other processes. The resulting ions are separated and detected in a second stage of mass spectrometry (MS²). Ephemeral tandem mass spectrometry involves multiple separation steps over time to achieve separation with ions trapped at the same location. A quadrupole ion trap or Fourier Transform Ion Cyclotron Resonance (FTICR) device can be used for such analysis. Trapping instruments can perform multiple analytical steps, sometimes referred to as MSn (MS to the n). Tandem mass tag (TMT) is an isobaric mass tag chemical label used for protein quantification and identification. The tag contains four regions: Mass reporters, cleavable linkers, mass normalization, and protein reactive groups. The TMT reagent can be used to simultaneously analyze 2-11 different peptide samples prepared from cells, tissues, or body fluids. There are many different tandem MS/MS experimental setups and each mode has its own application and provides different information. It involves using an ion trap. Fragmentation of gas-phase ions is essential for tandem mass spectrometry and occurs between different phases of mass spectrometry. There are many methods used to fragment ions, and these can lead to different types of fragmentation, thus yielding different information about molecular structure and composition of proteins. Tandem mass spectrometry can be used for protein sequencing. Apparently, the first difference in TEM lies in the chemical modification sites that globally map the protein's PTMs (e.g., identify phosphorylation, glycosylation, sulfonation sites, etc.).When intact proteins are introduced into the mass spectrometer, it is called 'top-down proteomics', and when proteins are breaked down into smaller peptides and subsequently introduced into the mass spectrometer, it is designated 'top-down proteomics' called “bottom-up proteomics”. Shotgun proteomics is a type of bottom-up proteomics that breaks proteins in a mixture prior to separation and tandem mass spectrometry. Tandem mass spectrometry can generate peptide sequence tags that can be used to identify peptides in protein databases. With these unique capabilities and broad access to common bench-top mass spectrometers, TEM plays an important role in the emerging field of protein mass spectrometry.