Quadrupole time-of-flight QTOF

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. 

Arora, V. K., Li, Y., Philip, T., Yeola, S., and Mayol, R. F. (2001). Automated high-throughput metabolite identification using quadrupole time-of-flight (QTOF 2) mass spectrometer. In Proceeding of the 49th ASMS Conference on Mass Spectrometry and Allied Topics, Chicago, IL. 

The ESI-LC/MS-based approaches that feature ion trap (Gatlin et al, 1998 Washburn et ah, 2001) and quadrupole time-of-flight (QTOF) (Blackburn and Moseley, 1999) mass spectrometers are routinely used for the identification and characterization of proteins. Nanoelectrospray LC/MS formats (Figure 6.3) are used to provide lower limits of detection and fully automated sample preconcentration and desalting. On-line LC/MS approaches for protein expression profiling are also used with ESI-TOF (Banks and Gulcicek, 1997 Chong et al., 2001) and ESI-Fourier transform (FT) (Kelleher... 

Figure 4.1 Schematic representations of a time-of-fl ight/time-of-fl ight (TOF/TOF) instrument with a matrix-assisted laser desorption/ionization (MALDI) source (a), and a quadrupole time-of-flight (qTOF) instrument which can be interchangeably...

To date, all tandem mass spectrometry in oTOF mass spectrometers has occurred in the front-end injection optics. These instruments are usually called quadrupole time-of flight (QTOF) instruments, because they start with a series... 

Figure 1.5 shows the determination of ion suppression of a PAH analysis in urine with APCI-quadrupole-time of flight (QTOF). During the analysis time between 80 and 400 s, the mass trace is considerably diminished and reaches the normal... 

Time-of-flight (TOF) analyzers have increased the popularity of high resolution MS, either alone or configured as hybrid quadrupole time of flight (QTOF) instruments. TOF provides sensitivity and selectivity somewhere between single stage and tandem MS. 

Tandem mass spectrometry analysis can be carried out in space or time. The former requires two or more mass analysers coupled together, a quadrupole time-of-flight (QTof) or a triple quad (QqQ), for example. Equally, tandem mass... 

Since the use of a QMF is not practical for a pulsed MALDI technique and because ESI often produces multiply charged ions, thus decreasing the ion s m/z, there has been little attempt commercially to increase the mass range of the QMF beyond miz 4000. However, several researchers have increased the QMF to mIz 9000 and 45,000. ° Sobott and co-work-ers ° showed that it was possible to analyze miz 22,000 within an isolation window of 22 Th on a quadrupole time-of-flight (QTOF) tandem mass spectrometer by lowering the QMF to 300 kHz. 

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