Triple quadrupole mass spectrometers resolution

It is evident from the data in Figure 3, that maximum gas-phase ion intensities for a given analyte ion are obtained with 10-4 to 10-3 mol/L analyte in the solution. The 3 x 106 ion counts/s observed at such concentrations are intensities after mass analysis at low resolution where the gas was admitted through a 100 pm orifice into a vacuum chamber which contains a triple quadrupole mass spectrometer.51... 

Triple quadrupole mass spectrometers, QqQ, have almost become a standard analytical tool for LC-MS/MS applications, in particular when accurate quantitation is desired (Chap. 12). Ever since their introduction [124-126] they have continuously been improved in terms of mass range, resolution, and sensitivity (Fig. 4.38). [127-129]... 

Thomson, B.A. Douglas, D.J. Corr, J.J. Hager, J.W. Jolliffe, C.E. Improved CID Efficiency and Mass Resolution on a Triple Quadrupole Mass Spectrometer. Anal Chem. 1995, 67, 1696-1704. 

Two more MS-related innovations are worth noting here (1) higher mass resolution on a triple quadrupole mass spectrometer and (2) atmospheric pressure... 

Xu, X. Veals, J. Korfmacher, W. A. Comparison of conventional and enhanced mass resolution triple-quadrupole mass spectrometers for discovery bioanalytical applications. Rapid Commun Mass Spectrom 2003, 17, 832-837. 

The most common types of MS/MS instruments available to researchers in food chemistry include triple quadrupole mass spectrometers and ion traps. Less common but commercially produced tandem mass spectrometers include magnetic sector instruments, Fourier transform ion cyclotron resonance (FTICR) mass spectrometers, and quadrupole time-of-flight (QTOF) hybrid instruments (Table A.3A.1). Beginning in 2001, TOF-TOF tandem mass spectrometers became available from instrument manufacturers. These instruments have the potential to deliver high-resolution tandem mass spectra with high speed and should be compatible with the chip-based chromatography systems now under development. 

Hughes, N., Winnik, W., Dunyach, J. J., Amad, M., Splendore, M., and Paul, G. (2003). High-sensitivity quantitation of cabergoline and pergolide using a triple-quadrupole mass spectrometer with enhanced mass-resolution capabilities. J. Mass Spectrom. 38 743-751. 

Both of the above examples illustrate that the sensitivity of the MDF method, in general, is comparable to PIS analysis and better than NLS methods (Figs 6.9 and 6.10). The sensitivity of the MDF method is attributed at least in part to the full-scan capability of high-resolution mass spectrometers such as the Q-TOF and LTQ-FTICR, which could be several times more sensitive than full-scan analysis by a triple-quadrupole mass spectrometer (Kostiainen et al., 2003). 

The mass spectrometer used by Banner and colleagues was a rapid scanning magnetic sector instrument that easily provided a resolution of one mass unit. Nowadays, mass spectrometers (giving vastly improved resolution) are mostly used with capillary columns and operated in a very similar manner, with the column eluent passing directly into the ionization source of the spectrometer. The most advanced system involves the triple quadrupole mass spectrometer, which gives extremely impressive in-line sensitivity, selectivity and resolution. 

Liquid chromatography-mass spectrometry (LC-ESI-MS) was performed on a PE-Sciex API-Ill triple quadrupole mass spectrometer with an lonSpray source. The samples were separated on the Nucleosil Cl 8 column with gradient 1 a splitting device was used to direct a portion of the effluent into the mass spectrometer. Data were acquired in the range of m/z 400-1000, with sufficient resolution to detect the isotope peaks for singly-charged ions at m/z 1000. 

BA Thomson, DJ Douglas, JJ Con, JW Hager, CLJolliffe. Improved collision-ally activated dissociation efficiency and mass resolution on a triple quadrupole mass spectrometer system. Anal Chem 67 1696—1704, 1995. 

A. Low-Resolution CE-MS AND CE-MS/MS Methods Using Triple Quadrupole Mass Spectrometers or Quadrupole Ion Traps... 

Increasing the resolution decreases the number of ions that reach the detector. Good resolution also depends on the quality of the machining for the quadrupole rods. Quadrupole rods can have other functions besides their use as a mass filter. An RF-only quadmpole will act as an ion guide for ions within a broad mass range. For example, the collision region of a triple quadrupole mass spectrometer uses an RF ion guide. A DC-only quadrupole is used as a lens element in some ion optical systems. 

The uptake of HRMS instrumentation into metabolite identification laboratories points to future developments and uses for these types of mass analyzers. From a hardware perspective, developments in TOF and Orbitrap technology will be needed to address lingering issues specific to these analyzers. In the TOF area, current commercial systems just coming to the market have addressed historical limitations of resolution, dynamic range, and mass accuracy. It remains to be seen if these specifications are sufficient or if further gains are needed. These instruments are not yet as sensitive as high-end triple quadrupole mass spectrometers, and improvements are needed in this area. For Orbitrap-based systems, the main limitations are scan speed and sensitivity. As... 

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