Mass resolving power establishing

TOF-MS (time of flight MS), with its high mass-resolving power is capable of generating mass data of sufficient accuracy and precision to establish the elemental composition of an analyte. The high accuracy, fast response time, and ease of peak deconvolution capability make TOF-MS an ideal online detector to interface with high-resolution separation techniques. The hyphenation of TOF-MS with CE... 

Da, we would need a resolution of (28.0061 - 27.9949) = 0.0112 Da in 28 Da. To convert this resolution to ppm, divide 0.0112 by 28 and multiply by 1 x 10 a resolution of 400 ppm is required. The resolving power needed would be 27.9949/0.00112 = 2500. Mass accuracy describes how well the top of the MS peak can be defined and kept stable and its position identified on the mass axis. Mass axis calibration is usually established by a separate portion of the tuning algorithm, which identifies the centroids of several mass peaks of precisely known mass in the spectrum of a suitable calibration compound and adjusts tuning parameters to place these at the appropriate positions on the mass axis. Like resolution, it can be expressed as a percentage or ppm value of the calibration mass values. 

Partial pressures of different species present in the vapour phase over Th02, UO2, UC, were studied at very high temperature (>3000 K), by transient heating of the sample with a 532 nm laser pulse of ca. 8 ns duration with time-resolved mass-spectrometric detection. The surface temperature was varied by changing the laser incident power on the sample. For Th02, the authors give partial pressures of Th(g), ThO(g), Th02(g) and 0(g) at 5146 and 6253 K. Since in this type of experiment, it is difficult to establish reliably the relevant temperatures, these data have not been used in the analysis. Never-... 

The exceptional power of separation and resolution, rapid analysis time, simplicity, versatility, low mass detection limits, economy of reagents, minimum sample requirements, and the possibility of direct sample injection without complex sample pretreatments make CE an attractive methodology to forensic scientists [104-106] where the sample matrix may be extremely complicated and contain a number of endogenous components which have to be resolved from the solute of interest. On the other hand, lack of sensitivity and maturity means that CE is not yet very well established in forensic laboratories as an additional tool to other analytical techniques. 

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