Spectral acquisition rates

Time-of-flight (TOF) MS does not suffer the same speed limitations of the previously mentioned instrument types, because the spectral acquisition rate is essentially determined by the transit time of the... 

As for all scanning instruments, the spectral acquisition rate depends on the m/z range required and on other factors, but a good quadrupole can typically scan and... 

While this level of mass measurement accuracy is rarely necessary in quantitative analyses, the fast spectral acquisition rates of TOFs have been used to advantage in methods employing extremely fast GC separations. Standalone TOF analyzers cannot readily mass select ions, thus precluding the use of SIM mode. As such, quantitative assays performed on TOFs must currently make use of full scan MS mode. Moreover, TOFs have a low duty cycle when operated with continuous ionization sources since the slowest (highest m/z) ions in one ion packet accelerated into the flight tube must be allowed to reach the detector before the next packet is selected. At the other extreme, TOF analyzers have an essentially 100% duty cycle when directly interfaced to pulsed ionization sources like MALDI if the ionization pulse is synchronized with the TOF acceleration. 

Electiopherogram of the separaticai of 0.2 mg/mL Co and 14 mg/mL cyanocobalamin in deionized water. Buffer conditions 75 mM Tiizma run buffCT, pH 8.0. Separation conditicais 4-s hydrodynamic injectirai via suction at 1/2 ambient pressure (380 mbar) and 10-kV run potential. Spectral acquisition rate, 0.1 s ... 

For the characterization (compound identification) of the bands eluting from a fast gas chromatographic separation, time-of-flight mass spectrometry (TOFMS) is unsurpassed. The two unique attributes of TOFMS that make it so well suited as a detector for HSGC are very high spectral acquisition rates and spectral continuity across the chromatographic peak profile for a single-component peak (31). 

Spectral acquisition rates of at least several hundred fuU-mass-range spectra per second can be achieved. High acquisition rates are needed in order to track the very narrow chromatographic peaks often associated with HSGC using short columns and high carrier-gas flowrates. 

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