Tandem information content

As an instrumental approach to conventional electrophoresis, capillary electrophoresis offers the capability of on-line detection, micropreparative operation and automation (6,8,45-47). In addition, the in tandem connection of capillary electrophoresis to other spectroscopy techniques, such as mass spectrometry, provides high information content on many components of the simple or complex peptide under study. For example, it has been possible to separate and characterize various dynorphins by capillary electrophoresis-mass spectrometry (33). Therefore, the combination of CE-mass spectrometry (CE-MS) provides a valuable analytical tool useful for the fast identification and structural characterization of peptides. Recently, it has been demonstrated that the use of atmospheric pressure ionization using Ion Spray Liquid Chromatography/ Mass Spectrometry is well suited for CE/MS (48). This approach to CE/MS provides a very effective and straightforward method which allow the feasibility of obtaining CE/MS data for peptides from actual biological extracts, i.e., analysis of neuropeptides from equine cerebral spinal fluid (33). 

The base composition and sequence of a circular dimer (10 /un circular duplex) suggest that two monomeric units are attached to each other to form a new circular molecule. The monomeric genomes are fused in a dimer in a head-to-tail tandem fashion. The informational content of monomers and dimers has been shown to be essentially the same [the homolo is at least 90 (Clayton et al., 1970)]. This special form of mt DNA is predominantly found in cells in culture and in neoplastic tissues. The percentage of these oligomers apparently varies if the culture... 

Zehl M, Pittenauer E, Jirovetz L, Bandhari P, Singh B, Kaul VK et al (2007) Multistage and tandem mass spectrometry of glycosylated triterpenoid saponins isolated from bacopa monnieri comparison of the information content provided by different techniques. Anal Chem 79 8214-8221... 

When analysis is performed on ion-trap instruments, this ion can be selected and subjected to further fragmentation. The resulting MS spectra are rich in structural information (Figure 2.15). The MS/MS spectra on tandem quadrupole or Q-TOF instruments are effectively a composite of MS2 and MS3 spectra recorded on an ion trap. Using our charge-tagging methodology, we have profiled the oxysterol content of adult, newborn, and... 

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