High resolution capability

The four-sector mass spectrometer is the ultimate in MS-MS instrumentation and consists of two high-resolution mass spectrometers in series. The strength of these instruments is in terms of their high-mass and high-resolution capabilities for both precursor-ion selection and product-ion analysis. Their cost, however, precludes their primary use for LC-MS and therefore they will not be considered any further here [12]. 

The resist has a high sensitivity and high resolution capability. The suitable photo absorption, excellent dissolution kinetics and no swelling during development contribute to such superior characteristics of this resist. 

The exposure curve of the two-layer resist based on the doping process is shown in Figure 8. The two-layer resist system has a high contrast and high resolution capability. Submicron line-and-space patterns are obtained using this two-layer resist system (Figure 9). 

Due to their fast acquisition rate and high resolution capabilities TOP mass analyzers are often used as the last mass analyzing stage in hybrid tandem mass... 

Carefully constructed Probe Mixtures based on small molecules and polystyrene standards are used as standardized reference points to better define the functional capabilities of individual columns and column combinations. The result using the method of Probe Mixtures to evaluate columns is better than can be attained from calibration curves alone and is especially useful in this high resolution capability situation. 

Doty Scientific, Inc. (Columbia, SC, USA) has been relatively successful in incorporating high resolution capabilities into their more standard solid-state MAS probes,32 where, in a traditional application, the extra care may not ever be noticed, but it provides the ability to use one MAS probe for both solid and gel-phase samples. They have introduced a sample insert that permits ready preparation of a number of samples that can be inserted into a MAS rotor for spectral acquisition, then preserved (or discarded) without requiring the dedication of a more expensive rotor. 

Capillary Electrophoresis. Capillary electrophoresis (ce) or capillary zone electrophoresis (cze), a relatively recent addition to the arsenal of analytical techniques (20,21), has also been demonstrated as a powerful chiral separation method. Its high resolution capability and lower sample loading relative to hplc makes it ideal for the separation of minute amounts of components in complex biological mixtures (22,23). 

The commercially available stand-alone LITs, marketed under the name LTQ, are made of four hyperbolic cross-sectional rods (Fig. 1.25). Since ions are trapped in an axial mode as opposed to central trapping on 3D ion traps, LTQs have been successfully coupled with Orbitrap and FTICR for achieving high-resolution capabilities (Peterman et al., 2005 Sanders et al., 2006) (Chapter 5). Functional improvements in 2D traps over 3D traps include 15 times increase in ion storage capacity, 3 times faster scanning, and over 50% improvement in detection efficiency and trapping efficiency. 

In conclusion, the sensitivity and specificity for screening for oxidative metabolites by the three LC-MS methods are variable, compound-dependent, and complementary to each other. The MDF method requires a simple, generic full-scan analysis using a mass spectrometer equipped with high-resolution capability, and the accurate mass information obtained can provide empirical formula information for metabolites and their fragments. Since MDF employs a different detection... 

An important current development is the use of LC combined with TOF instruments. These have the potential of high-resolution capability, accurate mass determination, and very rapid acquisition rates with detection of all ions transmitted by the flight tube. An LC/TOF instrument is being used... 

The advantages of the two coherent Raman techniques, stimulated Raman gain (SRGS) and inverse Raman spectroscopy (IRS), have been described in detail in Secs. 3.6.1.3 and 3.6.2.3. Here, we present an instructive example for each technique emphasizing the high resolution capability of the.se methods. 

While it is clearly apparent that packed columns are mainly used for the various compendial tests, the use of capillary columns for the determination of therapeutic agents in biological fluids has become increasingly popular. The high resolution capability of capillary columns often overcomes the problems of interference from the biological sample matrix and, coupled with specificity and increased sensitivity has made possible the quantitative analysis of many, formerly undeterminable drugs in biological fluids. In particular. 

Advances in the manufacture of flexible fused silica WCOT columns will almost certainly extend the applications of GC by virtue of their high-resolution capability, while the advent of sophisticated, computerized detectors forecast the improvement in sensitivity and specificity. The use of chiral stationary phases for the resolution of enantiomers is becoming an increasingly important topic in pharmaceutical analyses. The range and availability of various liquid phases for chiral analysis by GC is bound to make this technique extremely valuable for the assay of pharmaceutical raw materials as well as for use in biological fluids. 

Fig. 5 Schematic of a QTOF MS instrument. Ions formed in the source region are introduced into a quadrupole mass filter (Fig. 7) that separates ions based on mass-to-charge ratio (m/z). Selected ions are then transferred into the TOF MS for detailed analysis (i.e., high resolution capabilities). (Courtesy of Micromass, Manchester, UK.)...

Dabsyl chloride is an alternative to DABITC as a derivatization reagent to be used for manual sequencing. Dabsyl chloride reacts with primary and secondary amino acids forming red-orange derivatives that are stable for months. The method offers excellent sensitivity, ease, and speed of preparation and high-resolution capabilities. However, it suffers from interferences with ammonia present in biological samples. Furthermore, it results in a relatively reduced column lifetime due to the utilization of excess of Dabsyl chloride [9]. 

With high resolution capability one can find unique masses which are attributable to each molecule and from that Intensity and a library of mass spectral data ( ) one can "deconvclute" the mass spectrum Into its individual components. We currently have the ability tc acquire such data and are developing the software needed tc handle It. 

The increasingly rapid adoption of capillary column GC techniques promises an advance for inorganic separations as much by virtue of the absence of decomposition sites on supports or columns as by high resolution capabilities. This is particularly true for fused-silica capillary columns, which are characterized by extremely low residual trace metal concentrations in the silica matrix. 

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