Mass spectrometric method development

Mass spectrometric detector selectivity provides imequivocal identification of target compoimds. By targeting the MW and by using specific software, fully automated peak recognition is possible. Compoimds need to be efficiently ionized for their detection. The single-quadmpole Waters ZQ is equipped with the two commonly available ionization sources electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI). As most of the compounds to be examined were basic, electrospray with positive ionization was our method of choice. The selection of E SI was supported by previous experience gained over the last three years in our laboratory about 96% of the identified compounds, corresponding to more than 9,000 different molecules, were successfully analyzed with the ESI interface. 

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Zhang L-K. Mass spectrometric method development and application for elucidation of structure, sequence, and reactivity of oligodeoxynucleotides and their carcinogen adducts. Washington University, St. Louis, MO, 2001. 

Table 11-1 list-s the most important types of atomic mass spectrometry. Historically, thermal ionization mass spectrometry and spark source mass spectrometry were the first mass spectrometric methods developed for qualitative and quantitative elemental analysis, and these types of procedures still find applications, although they are now overshadowed by some of the other methods listed in Table 11-1, particularly inductively coupled plasma mass. spectrometry (fCPMS). 

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 ... 

In recent years, very effective mass-spectrometric methods have been developed for direct polymer... 

Various analytical methods have made quantum leaps in the last decade, not least on account of superior computing facilities which have revolutionised both data acquisition and data evaluation. Major developments have centred around mass spectrometry (as an ensemble of techniques), which now has become a staple tool in polymer/additive analysis, as illustrated in Chapters 6 and 7 and Section 8.5. The impact of mass spectrometry on polymer/additive analysis in 1990 was quite insignificant [100], but meanwhile this situation has changed completely. Initially, mass spectrometrists have driven the application of MS to polymer/additive analysis. With the recent, user-friendly mass spectrometers, additive specialists may do the job and run LC-PB-MS or LC-API-MS. The constant drive in industry to increase speed will undoubtedly continuously stimulate industrial analytical scientists to improve their mass-spectrometric methods. 

High performance liquid chromatography-mass spectrometric methods Nitin et al. [75] developed and validated a sensitive and selective liquid chromatography-tandem mass spectrometric method (LC MS MS) for the simultaneous estimation of bulaquine and its metabolites primaquine in monkey plasma. The mobile phase consisted of acetonitrile ammonium acetate buffer (20 mM, pH 6) (50 50, v/v) at a flow rate of 1 mL/min. The chromatographic separations were achieved on two Spheri cyano columns (5 pm, 30 cm x 4.6 mm), connected in... 

The rapid development and sensitivity of the mass spectrometric methods can be foreseen and in the near future the labeling can be more frequently eliminated. The identification of the cross-linked peptide can be detected first with immunological methods and then the digested and cleaved fragments with specific tandem MS techniques. The different photophores hold discrete MS fingerprints, which allow fast recognition of the modified sites. 

Tandem mass spectrometric methods have demonstrated superb specificity because of their ability to isolate analytes selectively in the presence of endogenous interferences. Attempts to further increase sample throughput led to the idea of using LC/MS/MS without the LC. Traditional chromatographic separations were replaced with flow injection analysis (FLA) or nanoelectrospray infusion techniques. The MS-based columnless methods attracted a lot of attention because of their inherent fast cycle times and no need for LC method development. 

An isotope dilution mass spectrometric method involves the addition of a known quantity of Tc followed by chemical separation, purification, and measurement of the Tc/ Tc isotopic ratio . An improved technique has been developed for the analysis of Tc in environmental samples. After spiking with Tc the isolated technetium is concentrated onto anion exchange beads. Determination of as little as 1 pg has been achieved through the enhanced ionization efficiency afforded by the resin bead source ... 

Mass spectrometry is more than 100 years old and has yielded basic results and profound insights for the development of atomic physics. The rapid development of nuclear physics, in particular, would be unthinkable without the application of mass spectrometric methods. Mass spectrometry has contributed to conclusive evidence for the hypothesis of the atomic structure of matter. So far mass spectrometry has supplied specific results on the structure of the nucleus of atoms. Nobel prizes have been awarded to a number of scientists (Thomson, Wien, Aston, Paul, Fenn and Tanaka) associated with the birth and development of mass spectrometry, or in which mass spectrometry has aided an important discovery (e.g., for the discovery of fullerenes by Curl, Kroto and Smalley). 

The only mass spectrometric methods available during the era of the first cascade synthesis in 1978 [30] were electron impact (El) and field desorption (FD) mass spectrometry [31]. Fast atom bombardment (FAB) mass spectrometry is limited to fairly low mass ranges and not very suitable for compounds of low polarity. It was not until the development of new and gentle ionisation methods such as MALDI (matrix-assisted laser desorption ionization) [32] and ESI (electrospray ionization) [33] that the conditions were fulfilled for the start of intense research in the field of dendrimer chemistry. The following section will present the special features of these mass-spectrometric methods and their importance in dendrimer analysis. 

Serodio, P. and J.M.F. Nogueira. 2005. Development of a stir-bar-sorptive extraction-liquid desorption-large-volume injection capillary gas chromatographic-mass spectrometric method for pyrethroid pesticides in water samples. Anal. Bioanal. Chem. 382 1141-1151. 

Kato K, Jingu S, Ogawa N, Higuchi S (2000) Development and validation of a liquid chromatographic-tandem mass spectrometric method for the determination of pibutidine in human urine. J ChromatogrB 740 187-193... 

Satonin DK, McCulloch JD, Kuo F et al (2007) Development and validation of aliquid chromatography-tandem mass spectrometric method for the determination of the major metabolites of duloxetine in human plasma. J Chromatogr B Anal Technol Biomed Life Sci 852 582-589... 

Naidong W, Eerkes A (2004) Development and validation of a hydrophilic interaction liquid chromatography-tandem mass spectrometric method for the analysis of paroxetine in human plasma. Biomed Chromatogr 18 28-36... 

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