Hybrid mass spectrometers for tandem mass spectrometry

Abstract

Mass spectrometers that use different types of analyzers for the first and second stages of mass analysis in tandem mass spectrometry (MS/MS) experiments are often referred to as "hybrid" mass spectrometers. The general goal in the design of a hybrid instrument is to combine different performance characteristics offered by various types of analyzers into one mass spectrometer. These performance characteristics may include mass resolving power, the ion kinetic energy for collision-induced dissociation, and speed of analysis. This paper provides a review of the development of hybrid instruments over the last 30 years for analytical applications. (J Am Soc Mass Spectrom 2008, 19, 161-172) © 2008 American Society for Mass Spectrometry T andem mass spectrometry (MS/MS), in a very generic description, is a process in which an ion formed in an ion source is mass-selected in the first stage of analysis, reacted, and then the charged products from the reaction are analyzed in the second stage of analysis. The type and quality of data that is obtained can vary greatly depending upon the type of analyzer used in the first and second stages of analysis, and the type of reaction performed between the stages of analysis. The reactions that can be done also can depend upon the type of analyzer. Over the years there have been a variety of means developed to measure the mass-to-charge ratio of gas-phase ions. The most common methods involve: dispersion based on ion momentum or kinetic energy (magnetic and electric sector instruments); separation in time based on ion velocity (time-of-flight); transmission through an electrodynamic field (quadrupole mass filter); and periodic motion in a magnetic or electrodynamic field (ion traps). There are differences in the experimental parameters associated with these various analysis methods that are pertinent to the MS/MS experiment. Some parameters are obvious, typically related to the performance of the mass analyzer while others are more subtle, related to the reactions/chemistry occurring between the stages of analysis. Many times these different parameters are used to categorize MS/MS experiments.One parameter is the ion kinetic energy. Sector and time-of-flight (TOF) instruments typically operate at "high" ion kinetic energies (5-20 keV), whereas "low" ion kinetic energies (Ͻ50 eV) are typical in quadrupole mass filters and ion traps. The ion kinetic energy is an important parameter in MS/MS experiments because the most common reaction involves colliding the ion of interest with a target gas atom or molecule. When performing ion-neutral collision experiments, the possible reactions that can be accessed (e.g., collisioninduced dissociation, collisional cooling, charge permutation, ion/molecule reaction) depends upon the ion kinetic energy. The appearance of the MS/MS spectrum can change drastically as a function of the collision (ion kinetic) energy. A related factor that is equally important, but often not considered, is the time frame of the experiment, that is, the elapsed time bet...

A Short Overview of the Components in Mass Spectrometry Instrumentation for Proteomics Analyses

“…The ion trap analyzers, such as quadruploe ion traps and orbitraps characterize ions based on the frequency of their motion in a defined space [15]. Thus MS and MS/MS events can be performed in the same analyzer, being separated by time and not by "space" [15,40]. The analyzers use magnetic or electric fields, or even combinations of both to select ions.…”

“…The mass analyzers characterize the ions according to their m/z. The ion selected in the first stage of analysis is subjected to different reactions and charged products from this reaction are analyzed in a second step (a second mass analyzer or other types of analyzers) [15]. The "reaction" step is critical for data quality and performance.…”

LC-MS/MS Based Metabolomics to Identify Biomarkers Unique to Laetiporus sulphureus

“…There has been tremendous progress in mass spectrometry-based metabolomics recently, leaving researchers with a variety of choices for chromatographic separation, ionization, and mass spectrometric analysis. Mass spectrometer options include quadrupoles and ion traps which offer good sensitivity but limited resolving power (Glish & Burinsky 2008), or higher mass-resolution instruments such as timeof-flight (TOF) (Lacorte & Fernandez-Alba 2006), Fourier transform ion cyclotron resonance (FTICR) (Kelleher et al 1999) or Orbitrap (Makarov et al 2006). The mass spectrometer can also be arranged in a tandem configuration, such as a triple quadrupole mass spectrometer.…”

Recent developments in qualitative and quantitative analysis of phytochemical constituents and their metabolites using liquid chromatography–mass spectrometry

“…The aim of MS/MS is either to get structure information by fragmenting the ions isolated during the first MS experiment, and/or to achieve better selectivity and sensitivity for quantitative analysis. The most commonly used tandem mass spectrometers include the triple quadrupole (QqQ or TQ), Q-Trap (Q-Linear Ion Trap), IT-IT (LTQ Orbitrap), Q-TOF and IT-TOF [39][40][41][42][43][44].…”