Selected electrospray ionization mass

M. J. Dubber, V. Sewram, N. Mshicileli, G.S. Shephard and I. Kanfer, The simultaneous determination of selected flavonol glycosides and aglycones in Ginkgo biloba oral dosage forms by high performance liquid chromatography electrospray ionization mass spectrometry, J. Pharmaceut. Biomed., 37, 723 731 (2005). 

McClean S, O Kane EJ, Smyth WR 2000. Electrospray ionization-mass spectrometric characterization of selected antipsychotic drugs and their detection and determination in human hair samples by liquid chromatography-tandem mass spectrometry. J Chromatogr B Biomed Sci Appl 740 141. 

The capacity of inositol orthoformate derivatives 124 and 125 for binding to alkali metal ions was studied by electrospray ionization mass spectrometry (ESI-MS) gas-phase measurements <2001JOC8629>. The [5.5.5]-iono-phore 125 n = 3) possessed the highest Li /Na selectivity and the best affinity for Li. The results obtained proved to be in agreement with the size-fit concept. Other factors which influence the complexation are the orientation of the oxygen atoms, which are able to bind to metal, the basicity, and the polarizability of the heteroatoms around the perimeter of the binding cavity. 

Liquid Chromatography-Electrospray Ionization Mass Spectrometric Characteristics ([M - H] and Product Ions) of Selected Proanthocyanidin Tetramers and Pentamers from Pinto Beans, Plums, and Cinnamon, Respectively... 

Marwah A, Marwah P, Lardy H (2001) Liquid chromatography-electrospray ionization mass spectrometric analysis of corticosterone in rat plasma using selected ion monitoring. J Chro-matogr 757 333-342... 

Electrospray Ionization/Mass Spectrometry (ES/MS), a soft-ionization desorption technique using polar solvents such as water, methanol, or acetonitrile, was used for direct measurement of cations in solution. The first measurements carried out with mono or bis(crown-6) calix[4]arenes from an equimolar cation-extractant solution confirm that the calixarenes mono(crown-6) extract only one cesium cation. On the contrary, in the same conditions, bis(crown-6) calix[4]arenes can extract two cesium cations for a ratio Cs/BC6 equal to 2.5. The binuclear complex (composed of two cesium cations) is the major species. Cesium/sodium selectivity measurements implementing various mono or bis(crown-6) calix[4]arenes were in agreement with liquid/liquid results.42... 

Complexation studies were carried out by electrospray ionization mass spectrometry (ESI-MS) with three lanthanides (La, Eu, and Yr) at a concentration of 10 4 M, while the ratio of concentration of CPw2 versus calixarene (r = [calix]org/[Ln]aq) was varied between 0.1 and 10.165 The behavior of the three lanthanides is the same the 1 1 Ln calix-CMPO complex is always predominant in the range of concentration studied the 2 1 Ln calix-CMPO appears in the case of metal excess with a maximum for r = 0.5, while the percent of 1 2 Ln calix-CMPO increases as the concentration of ligand increases, but does not exceed 10% for r = 10. These studies show that two factors play a key role in the selectivity of CMPO derivatives, firstly the presence of phenyl groups on the phosphorus atom, which confers the selectivity to CMPO ligands, secondly the calixarene structure, which amplifies this selectivity due to its preorganization. Indeed the noncyclic derivative (Os2), in spite of the presence of phenyl units, does not display noticeable selectivity. 

Phenomenex Luna 5- m C8(2) (250 mm x 4.6 mm i.d.) column Methanol-water (75 25, v/v) Electrospray ionization-mass spectrometry in selected ion-monitoring mode Determination in plasma in phase 1 human PK study [14]... 

A sensitive and rapid chromatographic procedure using a selective analytical detection method (electrospray ionization-mass spectrometry in SIM mode) in combination with a simple and efficient sample preparation step was presented for the determination of zaleplon in human plasma. The separation of the analyte, IS, and possible endogenous compounds are accomplished on a Phenomenex Lima 5-/rm C8(2) column (250 mm x 4.6 mm i.d.) with methanol-water (75 25, v/v) as the mobile phase. To optimize the mass detection of zaleplon, several parameters such as ionization mode, fragmentor voltage, m/z ratios of ions monitored, type of organic modifier, and eluent additive in the mobile phase are discussed. Each analysis takes less than 6 min. The calibration curve of zaleplon in the range of 0.1-60.0 ng/ml in plasma is linear with a correlation coefficient of >0.9992, and the detection limit (S/N = 3) is 0.1 ng/ml. The within- and between-day variations (RSD) in the zaleplon plasma analysis are less than 2.4% (n = 15) and 4.7% (n = 15), respectively. The application of this method is demonstrated for the analysis of zeleplon plasma samples [14]. 

Vreeken, R.J., P. Speksnijder, I. Bobeldijk-Pastorova, et al. 1998. Selective analysis of the herbicides gly-phosate and aminomethylphosphonic acid in water by on-line solid-phase extraction-high-performance liquid chromatography-electrospray ionization mass spectrometry. J. Chromatogr. A 794 187-199. 

Infrared spectroscopy has been rarely used for PolyP characterization (Datema et al, 1977). Electrospray ionization mass spectrometry (ESI-MS) has been applied to the characterization of phosphates (P , PP , PolyP3, PolyPs and tricyclophosphate). The high selectivity of ESI-MS allowed the detection of these compounds without any pre-separation by ion chromatography or capillary electrophoresis. The limits of detection for ESI-MS were estimated to be in the range from approximately 1 to 10 ng ml-1 (Choi et al, 2000). 

Guanidino-4-nitroimidazole formation in peroxynitrite-treated DNA was characterized by electrospray ionization mass spectrometry with selected reaction monitoring [409],... 

The on-line coupling of CE with electrospray ionization mass spectrometry (CE-ESI-MS) allows high separation efficiency together with high sensitivity and selectivity as well as molecular structural information. A CE-UV-ESI-MS method was developed for the analysis of hoscyamine, scopolamine, and other tropane derivatives [131]. The differentiation of hyoscyamine from littorine, commonly encountered in plant material, was demonstrated using in-source collision-induced dissociation. The developed method was applied to the analysis of these alkaloids in Belladonna leaf extract and in Datura Candida x D. awreahairy root extract. Recently, CE coupled with electrochemiluminescence detection has been used for the determination of atropine and scopolamine in Flos daturae [132]. 

Analyses of tropane alkaloids are mainly carried out by GC and HPLC and to a lesser extent by CE. This review describes recent applications developed for the analysis of this class of compounds in plant materials and biological matrices. Of course, mass spectrometry is generally used as the detection technique because of its high sensitivity and selectivity, but other techniques such as UV, fluorescence, flame ionization detection, nuclear magnetic resonance, among others have also been investigated. Finally, desorption electrospray ionization mass spectrometry is reported as a new interesting detection technique for the rapid analysis of samples without any sample preparation. 

Rosu, R Gabelica, V. Houssier, C. De Pauw, E. Determination of Affinity, Stoichiometry and Sequence Selectivity of Minor Groove Binder Complexes with Double-Stranded Oligodeoxynucleotides by Electrospray Ionization Mass Spectrometry, Nucleic Acids Research 30, E82/1-E82/9 (2002). 

Jiang, Y Lee, C.S. On-Line Coupling of Hollow Fiber Membranes with Electrospray Ionization Mass Spectrometry for Continuous Affinity Selection, Concentration and Identification of Small-Molecule Libraries, /. Mass Spectrom. 36, 664-669 (2001). 

Regarding MS detection, authors described methods performed in positive ion mode using full scan and selected ion monitoring for PSP analysis [42,43], The pioneering PSP research in the area of electrospray ionization-mass spectrometry (ESl-MS) detection analysis has been conducted in the group of Quilliam et al. [46, 47]. In their studies, the authors used LC separation before pneumatically assisted ESI. Detection limits as low as 30 pg were obtained for positive ions of several STX analogs [46]. 

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