@article {https://doi.org/10.1002/elps.202000228, title = {Quantification of the bisphosphonate alendronate using capillary electrophoresis mass spectrometry with dynamic pH barrage junction focusing}, journal = {ELECTROPHORESIS}, volume = {42}, number = {n/a}, year = {2021}, pages = {350{\textendash}359}, abstract = {

Abstract A quantitative method was developed for the direct identity confirmation and quantification of alendronate using CE-MS combined with a pH-assisted focusing technique, dynamic pH barrage junction focusing. A pH-induced variation in electrophoretic mobility led to online focusing of alendronate at the sample/pH barrage boundary, significantly improving the detection sensitivity. In addition, the use of a flow-through microvial CE electrospray interface and the multiple reaction monitoring mode of MS further improved the specificity and quantification capability of this technology. This quantitative method presented a wide linear dynamic range over 8\–2000\ ng/mL and an LOD of 2\ ng/mL. A 460-fold improvement in sensitivity was obtained when pH barrage junction focusing was applied during the CE process, in comparison to when normal CE was conducted without online sample stacking. The superior detection sensitivity over previously reported methods enables direct analysis of bisphosphonate compounds, eliminating tedious pre-column sample enrichment and derivatization. Validation of alendronate content in a commercial drug tablet further proved the reliability and power of this method. This simple method with no sample derivatization, superior sensitivity, and short run time (\<8\ min) is a promising alternative for accurate quantification of alendronate and other types of bisphosphonate compounds in both drug formulations and plasma samples.

}, keywords = {Alendronate, Ce, Dynamic pH barrage junction focusing, MS}, doi = {https://doi.org/10.1002/elps.202000228}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/elps.202000228}, author = {Zhao, Tingting and Wang, Lingyu and Li, Yueyang and Chen, Sijia and Wang, Rizhi and Chen, David D. Y.} } @article {2232, title = {Investigation of substituted-benzene dopants for charge exchange ionization of nonpolar compounds by atmospheric pressure photoionization}, journal = {Journal of the American Society for Mass Spectrometry}, volume = {19}, number = {7}, year = {2008}, note = {ISI Document Delivery No.: 329LWTimes Cited: 7Cited Reference Count: 24Robb, Damon B. Smith, Derek R. Blades, Michael W.}, month = {Jul}, pages = {955-963}, type = {Article}, abstract = {Atmospheric pressure photoionization (APPI) using a dopant enables both polar and nonpolar compounds to be analyzed by LC/MS. To date, the charge exchange ionization pathway utilized for nonpolar compounds has only been efficient under restrictive conditions, mainly because the usual charge exchange reagent ions-the dopant photoions themselves-tend to be consumed in proton transfer reactions with solvent and/or dopant neutrals. This research aims to elucidate the factors affecting the reactivities of substituted-benzene dopant ions; another, overriding, objective is to discover new dopants for better implementing charge exchange ionization in reversed-phase LC/MS applications. The desirable properties for a charge exchange dopant include low reactivity of its photoions with solvent and dopant neutrals and high ionization energy (IE). Reactivity tests were performed for diverse substituted-benzene compounds, with substituents ranging from strongly electron withdrawing (EW) to strongly electron donating (ED). The results indicate that both the tendency of a dopant{\textquoteright}s photoions to be lost through proton transfer reactions and its IE depend on the electron donating /withdrawing properties of its substituent(s): ED groups decrease reactivity and IE, while EW groups increase reactivity and IE. Exceptions to the reactivity trend for dopants with ED groups occur when the substituent is itself acidic. All told, the desirable properties for a charge exchange dopant tend towards mutual exclusivity. Of the singlysubstituted benzenes tested, chloro- and brornobenzene provide the best compromise between low reactivity and high IE. Several fluoroanisoles, with counteracting EW and ED groups, may also provide improved performance relative to the established dopants.}, keywords = {APPI, MASS-SPECTROMETRY, MECHANISM, MS, POTENTIALS, PROTON AFFINITY, SOLVENT}, isbn = {1044-0305}, url = {://000257870100007}, author = {Robb, D. B. and Smith, D. R. and Blades, M. W.} } @article {4255, title = {Complementary use of capillary gas chromatography mass spectrometry (ion trap) and gas chromatography inductively coupled plasma mass spectrometry for the speciation of volatile antimony, tin and bismuth compounds in landfill and fermentation gases}, journal = {Analyst}, volume = {123}, number = {5}, year = {1998}, note = {ISI Document Delivery No.: ZN568Times Cited: 40Cited Reference Count: 183rd International Symposium on Speciation of Trace Elements in Biological, Environmental and Toxicological SciencesSEP 15-19, 1997PORT DOUGLAS, AUSTRALIAUniv New S Wales, Natl Inst Occupat Hlth, McMaster Univ, Inst Environ \& Hlth, MAFF, CSL, Food Sci Lab}, month = {May}, pages = {815-820}, type = {Proceedings Paper}, abstract = {ICP-MS is very sensitive and has limited matrix effects when used as an element-specific detector for GC in order to identify volatile metal or metalloid species, GC-MS is not very sensitive or selective in the electron ionization (EI) mode, but provides molecular information about volatile species. In this work, an ion trap EI-MS-MS and an ICP-MS system were used as two different detectors for the same GC system to provide complementary information about volatile organometallic species in the complex matrices of landfill and sewage sludge fermentation gases. A simple robust GC separation method with cryotrapping was adequate for the separation of the different metal(loid) containing volatile compounds, and was directly coupled to the ICP-MS system, In addition, gas samples from this GC system were collected in evacuated vials. These fractions were further separated on a capillary column and detected in an ion trap mass spectrometer. For the first time, parent ions, fragmentation patterns, isotopic ratios for Sb and Sn, and MS-MS data were used to identify positively Me3Sb, Me4Sn and Et2Me2Sn in landfill gas and Me3Sb and Me3Bi in fermentation gas.}, keywords = {ELEMENTS, fermentation gas, gas chromatography-inductively coupled, ion trap mass spectrometry, landfill gas, MASS SPECTROMETRY, METAL, MS, organometallics, ORGANOTIN COMPOUNDS, trimethylbismuthine, trimethylstibine, VOLATILE, WASTE DEPOSITS}, isbn = {0003-2654}, url = {://000073658900010}, author = {Feldmann, J. and Koch, I. and Cullen, W. R.} } @article {6841, title = {LASER DESORPTION IONIZATION FOURIER-TRANSFORM ION-CYCLOTRON RESONANCE MASS-SPECTROMETRY OF CARBOHYDRATES .1. BACTERIAL OLIGOSACCHARIDES CONTAINING NEURAMINIC ACID OR PYRUVIC-ACID ACETAL GROUPS}, journal = {Analytica Chimica Acta}, volume = {241}, number = {2}, year = {1990}, note = {ISI Document Delivery No.: EU533Times Cited: 14Cited Reference Count: 342ND INTERNATIONAL SYMP ON APPLIED MASS SPECTROMETRY IN THE HEALTH SCIENCESAPR 17-20, 1990BARCELONA, SPAINASTRA, APPL BIOSYST, BOEHRINGER MANNHEIM, COMISSIO INTERDEPT RECERCA \& INNOVAC TECHNOL, CONSEJO SUPER INVESTIGAC CIEN, CONSELLERIA ENSENYAMENT GENERALITAT CATALUNYA, FINNIGAN MAT, FONDO INVESTIGAC SANITARIA, REAL SOC ESPANOLA QUIMICA, GRP CROMATOG \& TECN AFINES, HEWLETT PACKARD}, month = {Dec}, pages = {187-199}, type = {Proceedings Paper}, abstract = {The positive- and negative-ion laser desorption ionization Fourier transform ion cyclotron resonance mass spectra of two known, underivatized, linear oligosaccharides obtained by enzymatic hydrolysis with bacterial viruses of the corresponding native bacterial capsular polysaccharides were analyzed. The high-resolution spectra, estimated to be from less than 1 nmol of sample, showed prominent pseudo-molecular ions, as well as fragment ions derived from glycosidic bond and ring cleavages. For some of these frequently observed ring fragments, structures are proposed by analogy to known even-electron gas phase fragmentations and even-electron solution chemistry. The structures of the capsular biopolymers were delineated from these fragmentations, confirming that Klebsiella pneumoniae serotype K3 capsular polysaccharide is made up of a pentasaccharide repeating unit, consisting of four hexoses, one hexuronic acid and one pyruvic acid acetal; and confirming that the tetrasaccharide repeating unit of Escherichia coli serotype K9 is composed of two hexoses, one acetamido hexose and one N-acetyl neuraminic acid. The analysis of oligosaccharides containing N-acetylated sugars was complicated by the fact that an amino hexose attached to a -C2H3O2 ring fragment shares the same elemental formula as an acetamido hexose. Nevertheless, other less ambiguous structural ions could be used for sequencing. Furthermore, analysis of the ring fragments also provided some indication of the positions of linkage of certain monosaccharide residues.}, keywords = {BACTERIOPHAGE-BORNE ENZYMES, CAPSULAR, FAB, FAST ATOM BOMBARDMENT, GLYCOSIDES, ION CYCLOTRON RESONANCE, LASER DESORPTION IONIZATION, MS, OLIGOSACCHARIDES, POLYSACCHARIDE, SEQUENCE, SPECTRA}, isbn = {0003-2670}, url = {://A1990EU53300004}, author = {Lam, Z. and Comisarow, M. B. and Dutton, G. G. S. and Parolis, H. and Parolis, L. A. S. and Bjarnason, A. and Weil, D. A.} }