Mass spectrometric analysis modification

Several modifications of the ESI technique have been introduced, principally micro-electrospray14 and nano-electrospray15 that have the advantage of using much lower flow rates, reducing the amount of analyte needed for a mass-spectrometric analysis this is performed using adapted probed tips. When performing nanospray, the sample is loaded into a fine hollow needle with a... 

A. Mass Spectrometric Analysis on the in Vivo Post-translational Modifications... 

Ice samples are put into pre-cooled extraction vessels for evacuation. The ice is then melted and a gas extraction and purification similar to that used for water samples is performed. Because dynamic analysis requires far more sample than the static mode, ultrapure N2 is added to increase bulk pressure by a factor of 10. The mass spectrometric analysis follows conventional procedures of dynamic isotope ratio mass spectrometry, with modifications designed to avoid any fractionating effects, such as thermal diffusion... 

An interesting modification of optical excitation especially for the accurate determination of isotope shifts is a combination of resonance excitation / ionisation and a mass spectrometric analysis of the ions created as it is realized in RIMS (resonance ionization mass spectrom-... 

An article on the mass-spectrometric analysis of g.l.c. effluents has been published, together with reviews on g.l.c. in combination with mass spectroscopy and with infrared spectroscopy. Although combined g.l.c.-m.s. instruments may be purchased, it is often found necessary to adapt existing apparatus. Several papers give details of such modifications for instance, constructional details for a probe to fit the AEI MS-9 have been published, a simple heated inlet system has been described, and molecule separators have been discussed. Methods for interfacing g.l.c. and m.s. instruments have been reviewed by D. I. 

Trester-Zedlitz, M., Burlingame, A., Kobilka, B., and Von Zastrow, M. (2005) Mass spectrometric analysis of agonist effects on posttranslational modifications of the beta-2 adrenoceptor in manunalian cells. Biochemistry, 44, 6133-6143. 

Machida M., Eguchi K., Arai H. Effect of structural modification on the catalytic property of Mn-substituted hexaaliminate. J. Catal. 1990 123 477 85 Machida M., Shiomitsu T, Eguchi K., Haneda A., Arai H. secondary-ion mass spectrometric analysis of anisotoropic oxygen self-diffusion in barium hexaaluminate single crystals. J. Mate. Chem. 1992 2 455-458... 

For the mass spectrometric analysis of peptides, the two ionization techniques are similarly complementary as they are for proteins [38]. Today, most mass spectrometers equipped with an ESI or a MALDI source provide the possibility of isolating analyte ions on the basis of their m/z ratio and, by different activation methods, transfer energy to them which results in their decomposition. Mass analysis of the resulting fragment ions can provide detailed structural information and is termed tandem-MS or MS/MS analysis (Fig. 2). Electrostatic ion traps and FT-ICR analyzers also provide multiple stages of ion isolation and fragmentation experiments (MS ), of which MS is especially useful for protein identification and modification analyses. 

Laser based mass spectrometric methods, such as laser ionization (LIMS) and laser ablation in combination with inductively coupled plasma mass spectrometry (LA-ICP-MS) are powerful analytical techniques for survey analysis of solid substances. To realize the analytical performances methods for the direct trace analysis of synthetic and natural crystals modification of a traditional analytical technique was necessary and suitable standard reference materials (SRM) were required. Recent developments allowed extending the range of analytical applications of LIMS and LA-ICP-MS will be presented and discussed. For example ... 

Several different methods exist for measuring HN03, most commonly FTIR and TDLS, which were described earlier. Other techniques commonly used include filters, denuders, transition flow reactors, and scrubbers, followed by analysis of the collected material for nitrate, e.g., by ion chromatography. A modification of the luminol method has also been used. Finally, mass spectrometric methods look very promising as a sensitive and specific method of detection and measurement. A brief description of each of these methods that have not yet been treated follows. 

With respect to sample preparation, it is necessary to develop effective and fast procedures involving only a few steps in order to avoid contamination, reduce analysis time and to improve the quality of analytical work. Microsampling and the use of smaller sample sizes is required and also the further development of analytical techniques. In particular, there is a need for the development of online and/or hyphenated techniques in ICP-MS. Microsampling combined with the separation of small amounts of analytes will be relevant for several chromatographic techniques (such as the development of micro- and nano-HPLC). There is a demand for further development of the combination of LA-ICP-MS as an element analytical technique with a biomolecular mass spectrometric technique such as MALDI- or ESI-MS for molecular identification and quantification of protein phosphorylation as well as of metal concentrations, this also enables the study of post-translational modifications of proteins, e.g. phosphorylation. 

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