Ionization mass spectrometric methods

The electron capture negative ion chemical ionization mass spectrometric method [58] discussed in section 5.6.1.6 for the determination of polychlorobiphenyls in soils has also been applied to sludges. 

Jones RM et al (1996) On-line high-performance liquid chromatographic-electrospray ionization mass spectrometric method for the study of tamoxifen metabolism. J Chromatogr A 722 249-255... 

Siluk D, Mager DE, Gronich N, Abernethy D, Wainer IW (2007) HPLC-atmospheric pressure chemical ionization mass spectrometric method for enantioselective determination of R, S-propranolol and R, S-hyoscyamine in human plasma. J Chromatogr B 859 213-221... 

Chan E, Ho P. High-performance liquid chromatog-raphy/atmospheric pressure chemical ionization mass spectrometric method for the analysis of catecholamines and metanephrines in human urine. Rapid Commun Mass Spectrom 2001 14 1959-64. 

Liang, Y., Xie, L., Liu, X.D., Chen, W.D., Lu,T, Xiong, Y, Wang, G.J. (2006) Simple, sensitive and rapid liquid chromatography/atmospheric pressure chemical ionization mass spectrometric method for the quantification of Ranolazine in rat plasma. Rapid Commun. Mass Spectrom, 20,523-528. 

Isotopic uranium composition by multiple-filament surface ionization mass spectrometric method... 

For the observation of neutral species in the solution phase, the first problem is how to make the species become ions. As a first example, Peter Chen et al. reported an electrospray ionization mass spectrometric method for the identification of uncharged active species in a solution phase ROM P reaction based on derivatization of the active species with a charged substrate [28]. 

Different gentle ionization mass spectrometric methods have been used in macromolecular analysis. MALDl-ToF... 

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 ... 

Cuyckens F and Claeys M. 2002. Optimization of a liquid chromatography method based on simultaneous electrospray ionization mass spectrometric and ultraviolet photodiode array detection for analysis of flavonoid glycosides. Rapid Commun Mass Spectrom 16(24) 2341—2348. 

Moody DR, Laycock JD, Huang W, Foltz RL. 2004. A high-performance liquid chromatographic-atmospheric pressure chemical ionization-tandem mass spectrometric method for determination of risperidone and 9-hydroxyr-isperidone in human plasma. J Anal Toxicol 28 494. 

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 ... 

In summary, the use of mass spectrometric methods, combined with various approaches to vaporizing and ionizing the particles, is gaining increasing popularity and interest for the analysis of continuous sources of particles or single particles. The problem of quantification of the components seen by single-particle laser ionization techniques remains to be solved. On the other hand, the vaporization approaches can provide quantitative data on some volatile and semivolatile components but cannot measure the nonvolatile species and, at present, do not provide a full mass spectrum for a single particle. 

The glow discharge ion source is simple yet versatile, providing information for emission and mass spectrometric methods.92 A glow discharge ion source combined with a mass spectrometer has supplanted the spark ion source over many decades as the predominant ionization technique of mass spectrometry for determining trace and ultratrace element concentrations in various types of... 

These energy values are calculated from thermochemical tables (11) and the ionization potentials of hydrocarbons obtained by Stevenson (15) using mass spectrometric methods. The union of an olefin and a proton from an acid catalyst leads to the formation of a positively charged radical, called a carbonium ion. The two shown above are sec-propyl and fer -butyl, respectively. [For addition to the other side of the double bond, A 298 = —151.5 and —146 kg.-cal. per mole, respectively. For comparison, reference is made to the older (4) values of Evans and Polanyi, which show differences of —7 and —21 kg.-cal. per mole between the resultant n- and s-propyl and iso-and tert-butyl ions, respectively, against —29.5 and —49 kg.-cal. per mole here. These energy differences control the carbonium ion isomerization reactions discussed below.]... 

A direct mass spectrometric method for simultaneous detection of five benzimidazoles including levamisole, thiabendazole, mebendazole, fenbendazole, and febantel in sheep milk was reported (377). The method, which involves injection of crude milk extracts and selection and collision of the most abundant ionic species obtained under electron impact ionization, was highly sensitive and rapid. Another direct mass spectrometric approach for rapid and quantitative determination of phenothiazine in milk was also described (323). This method involves an extraction step using a Cig microcolumn disc, followed by thermal desorption of the analyte from the disc directly into an ion trap mass spectrometer. 

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