Mass capabilities required

The mass range requirement invariably means that FAB is used in conjunction with a magnetic sector instrument. Conventional detectors, such as the electron multiplier, are not efficient for the detection of large ions and the necessary sensitivity is often only obtained when devices such as the post-acceleration detector or array detector are used. Instruments capable of carrying out high-mass investigations on a routine basis are therefore costly and beyond the reach of many laboratories. 

In contrast to the isospecific /(-symmetric metallocenes, which required 20 years of structural improvement in order to achieve acceptable molecular mass capability and high isotacticity, in the case of /(-symmetric complexes, the evolution from the original Me2C(Cp)(9-Flu)ZrCl2 (65, Table 13) resulted very early in the complex... 

The ionization source and mass analyzer of a mass spectrometer are inextricably linked, for the mass analyzer requires a particle be charged in order to separate it from other ions or neutral components. Any mass analyzer contains some electric or magnetic field, or combination of the two, which is capable of manipulating the trajectory of the ion in a vacuum chamber. Integration of an ionization source and mass analyzer must maintain the integrity of the vacuum, and the complexity of the engineering involved is largely dependent on the ionization technique. 

In most GC-TOF-MS instruments, an appropriate voltage pulse is applied to accelerate the ions in the direction orthogonal to their initial flight direction. In such oa-TOF-MS a nearly parallel ion beam ideally has no velocity spread, and the finite spatial spread is corrected with a linear or reflecting instrument geometry. Noise-free mass spectra are produced within a very short time (a few milliseconds). Only TOF-MS instruments have the capability required to detect peaks in GC GC since the half widths of the peaks eluting from the second column are of the order of 200 msec. Selecting the proper scan rate is essential since an increase in the acquisition speed... 

The mass transfer requirement stipulates that the patella (connecting strip) cannot be larger than 5 mm in width. If the patella is larger than that, a droplet will form on the surface, which will effectively reduce the wetted surface available for the reaction. If the patella is less than 5mm in width, the liquid is capable of moving over the surface without accumulating. The result is that the operating range is widened. The downside is that as the width is decreased, the pressure drop increases. This increase may limit the economics of the process. 

The extraordinary high-mass capabilities of ESI allow for the analysis of proteins and protein conplexes far beyond 10 u (> 1 MDa) [12,13,19,171,172], Even though the resulting ions are formed in very high charge states special mass analyzers with an expanded m/z range are required for this type of research. 

But it should be emphasized that while a reactive gas efficiently removes interferences, it is also capable of creating new interferences if not properly controlled. For that reason, an optimized reaction cell (coupled with a single mass analyzer) requires the use of a scanning quadrupole to prevent these new interferences from forming through the creation of a unit-resolution bandpass filter, in order to allow only a single mass to pass through. 

Future development will continue for a highly productive multi-compound trace analysis for the quantitation of mostly regulated target compounds. In addition, especially to comply with the aspects of food safety and product-safety requirements also non-targeted analytical techniques for the identification of potentially hazardous contaminants will evolve applying combined full scan and accurate mass capabilities. 

The isomerization proclivity of a reactive intermediate can be interrogated by measuring the tandem mass spectrum of the survivor ion. This capability requires that the instrumentation available be equipped with an additional mass analyzing device after the one used for the mass separation of the NR products. 

Due to the obtained purity of the urine extracts combined with the high resolution and accurate mass capability of the analytical instrumentation, 72 stimulants and metabolites, 21 narcotics and metabolites, 10 P2-agonists, and 31 P-blockers are, besides numerous additional compounds, simultaneously detected at minimum required performance levels. ... 

Product diameter is small and bulk density is low in most cases, except prilling. Feed hquids must be pumpable and capable of atomization or dispersion. Attrition is usually high, requiring fines recycle or recoveiy. Given the importance of the droplet-size distribution, nozzle design and an understanding of the fluid mechanics of drop formation are critical. In addition, heat and mass-transfer rates during... 

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