@article {2612,
	title = {Comparison of Dopants for Charge Exchange Ionization of Nonpolar Polycyclic Aromatic Hydrocarbons with Reversed-Phase LC-APPI-MS},
	journal = {Journal of the American Society for Mass Spectrometry},
	volume = {20},
	number = {1},
	year = {2009},
	note = {ISI Document Delivery No.: 393RRTimes Cited: 4Cited Reference Count: 16Smith, Derek R. Robb, Damon B. Blades, Michael W.},
	month = {Jan},
	pages = {73-79},
	type = {Article},
	abstract = {Atmospheric pressure photoionization (APPI) is capable of ionizing nonpolar Compounds in LC/MS, through charge exchange reactions following photoionization of a dopant. Recently, several novel dopants-chlorobenzene, bromobenzene, 2,4-difluoroanisole, and 3-(trifluoromethyl)anisole-have been identified as having properties making them well-suited to serve as dopants for charge exchange ionization under reversed-phase LC conditions. Here, we report the results of experiments comparing their effectiveness to that of established dopants-toluene, anisole, and a toluene/anisole Mixture, for the charge exchange ionization of model nonpolar compounds-the 16 polycyclic aromatic hydrocarbons (PAHs) identified by the US EPA as priority pollutants-when using a conventional reversed-phase LC method. Chloro- and bromobenzene were found to be much more effective than toluene for all the PAHs, due to the relatively low reactivity of their photoions with the solvent. Their overall performance was also better than that of anisole, due to anisole{\textquoteright}s ineffectiveness toward higher-IE compounds. Further, the experiments revealed that anisole{\textquoteright}s performance for higher-IE compounds can be dramatically improved by introducing it as a dilute Solution in toluene, rather than neat. The two fluoroanisoles provided the highest overall sensitivity, by a slim margin, when introduced as dilute solutions in either chloro- or bromobenzene. (J Am Soc Mass Spectrom 2009, 20, 73-79) (C) 2009 Published by Elsevier Inc. on behalf of American Society for Mass Spectrometry},
	keywords = {ATMOSPHERIC-PRESSURE PHOTOIONIZATION, ENERGIES, LC/MS, MASS-SPECTROMETRY, PROTON, SOLVENT},
	isbn = {1044-0305},
	url = {<Go to ISI>://000262390900011},
	author = {Smith, D. R. and Robb, D. B. and Blades, M. W.}
}
@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 = {<Go to ISI>://000257870100007},
	author = {Robb, D. B. and Smith, D. R. and Blades, M. W.}
}
@article {5004,
	title = {The methanol-induced conformational transitions of beta-lactoglobulin, cytochrome c, and ubiquitin at low pH: A study by electrospray ionization mass spectrometry},
	journal = {Journal of the American Society for Mass Spectrometry},
	volume = {12},
	number = {3},
	year = {2001},
	note = {ISI Document Delivery No.: 408WBTimes Cited: 45Cited Reference Count: 51},
	month = {Mar},
	pages = {317-328},
	type = {Article},
	abstract = {The methanol-induced conformational transitions under acidic conditions for beta -lactoglobulin, cytochrome c, and ubiquitin, representing three different classes of proteins with beta -sheets, alpha -helices, and both alpha -helices and beta -sheets, respectively, are studied under equilibrium conditions by electrospray ionization mass spectrometry (ESI-MS). The folding states of proteins in solution are monitored by the charge state distributions that they produce during ESI and by hydrogen/deuterium (H/D) exchange followed by ESI-MS. The changes in charge state distributions are correlated with earlier studies by optical and other methods which have shown that, in methanol, these proteins form partially unfolded intermediates with induced ct-helix structure. Intermediate states formed at about 35\% methanol concentration are found to give bimodal charge state distributions. The same rate of H/D exchange is shown by the two contributions to the bimodal distributions. This suggests the intermediates are highly flexible and may consist of a mixture of two or more rapidly interconverting conformers. H/D exchange of proteins followed by ESI-MS shows that helical denatured states, populated at around 50\% methanol concentration, transform into more protected structures with further increases in methanol concentration, consistent with previous circular dicroism studies. These more protected structures still produce high charge states in ESI, similar to those of the fully denatured proteins. (C) 2001 American Society for Mass Spectrometry.},
	keywords = {2-DIMENSIONAL NMR, ALPHA-HELIX, AMIDE HYDROGEN-EXCHANGE, COMPLETE SEQUENCE, DENATURED STATES, DEUTERIUM-EXCHANGE, INTERMEDIATE, MYOGLOBIN, PROTEIN, SOLVENT},
	isbn = {1044-0305},
	url = {<Go to ISI>://000167349200010},
	author = {Babu, K. R. and Moradian, A. and Douglas, D. J.}
}
@article {4394,
	title = {Determination of dissolved metal species by electrospray ionization mass spectrometry},
	journal = {Analytical Chemistry},
	volume = {70},
	number = {11},
	year = {1998},
	note = {ISI Document Delivery No.: ZR483Times Cited: 49Cited Reference Count: 50},
	month = {Jun},
	pages = {2225-2235},
	type = {Article},
	abstract = {The distribution of metal species in solution was determined using now injection electrospray ionization mass spectrometry. Complexes formed by selected metal ions with added organic ligands in 50:50 water/acetonitrile and 50:50 water/methanol under acidic, neutral, and basic conditions were detected using electrospray ionization conditions optimized to best represent solution-phase interactions. Metal species containing acetate, nitrate, and solvent molecules predominated in acidic solution but became less abundant at higher pH. Interactions between metal ions and added organic ligands became more selective with increasing pH, showing the expected preference of hard and soft ligands for metal ions:of the corresponding type. Species distributions also tended toward larger complexes as pH increased. Overall ion yield was greater for aqueous acetonitrile than for aqueous methanol solutions; however, reduction of copper(II) in aqueous acetonitrile resulted in the detection of copper(I) complexes for certain ligands. Experimental results for copper(II) and 8-hydroxyquinoline in 50:50 water/methanol showed good agreement with aqueous speciation predicted using the thermodynamic equilibrium model MINEQL. Detection of neutral complexes was achieved by protonation, deprotonation, or electrochemical oxidation during electrospray.},
	keywords = {COMPLEXES, copper, GAS-PHASE, LIGANDS, PHASE ION CHEMISTRY, PROTEINS, SOLVENT, SPECIATION, STOICHIOMETRY},
	isbn = {0003-2700},
	url = {<Go to ISI>://000073981600011},
	author = {Ross, A. R. S. and Ikonomou, M. G. and Thompson, J. A. J. and Orians, K. J.}
}
@article {3961,
	title = {Chiral and achiral diphosphine complexes of ruthenium(II) incorporating labile nitrile ligands: Synthesis and solution chemistry of mono- and dinuclear derivatives of Ru2Cl4(PP)(2) (PP equals chelating diphosphine)},
	journal = {Inorganic Chemistry},
	volume = {36},
	number = {9},
	year = {1997},
	note = {ISI Document Delivery No.: WW128Times Cited: 25Cited Reference Count: 36},
	month = {Apr},
	pages = {1961-1966},
	type = {Article},
	abstract = {A family of nitrile complexes has been prepared by reaction of Ru2Cl4(PP)(2) Or RuCl2(PP)(PPh3) (PP = Ph2P(CH2)(4)PPh2 (dppb), Ph2PCH2CHOCMe2OCHCH2PPh2 (diop), 2,2{\textquoteright}-bis(diphenylphosphino)-1, 1{\textquoteright}-binaphthyl (binap)) with MeCN or PhCN, the product formed depending strongly on the reaction conditions. At high nitrile concentrations, the principal species present is RuCl(PP)(RCN)(3)X-+(-) (X = Cl); the cation can generally be isolated (as the PF6 salt) by abstraction of the chloride counterion with NH4PF6. Use of 2 equiv of NH4PF6 generates Ru(PP)(RCN)(4)(2+)(PF6-)(2) (PP = dppb). In the absence of a halide-abstracting agent, addition of hexanes or diethyl ether precipitates neutral RuCl2(PP)(RCN)(2) species, which undergo further loss of nitrile in the solid state (R = Me) or in solution (R = Me, Ph). Redissolution of the neutral species in chlorocarbon solvents gives Ru2Cl3(PP)(2)(RCN)(2)X-+(-) (X = Cl) and, in benzene, Ru2Cl4(PP)(2)(RCN). The dinuclear cation (X = PF6) is also accessible by reaction of RuCl(PP)(RCN)(3)+PF6- with CH2Cl2 or CDCl3, while the mononitrile can be obtained directly by reaction of Ru2Cl4(PP)(2) or RuCl2(PP)(PPh3) with small amounts of nitrile in benzene.},
	keywords = {ACTIVATION, ACTIVITY, CARBOXYLIC-ACIDS, CATALYTIC, DICHLOROMETHANE, DIHYDROGEN, DITERTIARY-PHOSPHINE COMPLEXES, GENERATION, HYDROGENATION, OXIDATIVE-ADDITION-REACTIONS, SOLVENT},
	isbn = {0020-1669},
	url = {<Go to ISI>://A1997WW12800034},
	author = {Fogg, D. E. and James, Brian R.}
}
@article {3846,
	title = {Characteristics of an inductively coupled argon plasma operating with organic aerosols .4. Noise power spectra},
	journal = {Journal of Analytical Atomic Spectrometry},
	volume = {11},
	number = {11},
	year = {1996},
	note = {ISI Document Delivery No.: VT965Times Cited: 3Cited Reference Count: 31},
	month = {Nov},
	pages = {1011-1018},
	type = {Article},
	abstract = {With the use of noise power spectra it is shown that the vortex shedding frequency depends on the solvent and the solvent plasma load, and modulates both the plasma boundary and analyte plume of the discharge.},
	keywords = {ATOMIC EMISSION-SPECTROMETRY, DROPLETS, FLOW TORCH, fluctuations, INDUCTIVELY COUPLED ARGON PLASMA, jet, LOAD, MASS-SPECTROMETER, noise power spectra, ORGANIC SOLVENT, SOLVENT, SOLVENT PLASMA LOAD},
	isbn = {0267-9477},
	url = {<Go to ISI>://A1996VT96500002},
	author = {Weir, D. G. and Blades, M. W.}
}
@article {3800,
	title = {Secondary structure and NMR assignments of Bacillus circulans xylanase},
	journal = {Protein Science},
	volume = {5},
	number = {6},
	year = {1996},
	note = {ISI Document Delivery No.: UP617Times Cited: 23Cited Reference Count: 74},
	month = {Jun},
	pages = {1118-1135},
	type = {Article},
	abstract = {Bacillus circulans xylanase (BCX) is a member of the family of low molecular weight endo-beta-(1,4)-xylanases. The main-chain H-1, C-13, and N-15 resonances of this 20.4-kDa enzyme were assigned using heteronuclear NMR experiments recorded on a combination of selectively and uniformly labeled protein samples. Using chemical shift, NOE, J coupling, and amide hydrogen exchange information, 14 beta-strands, arranged in a network of three beta-sheets, and a single cy-helix were identified in BCX. The NMR-derived secondary structure and beta-sheet topology agree closely with that observed in the crystal structure of this protein. The H-N of Ile 118 has a strongly upfield-shifted resonance at 4.03 ppm, indicative of a potential amide-aromatic hydrogen bond to the indole ring of Trp 71. This interaction, which is conserved in all low molecular weight xylanases of known structure, may play an important role in establishing the active site conformation of these enzymes. Following hen egg white and bacteriophage T4 lysozymes, B. circulans xylanase represents the third family of beta-glycanases for which extensive NMR assignments have been reported. These assignments provide the background for detailed studies of the mechanism of carbohydrate recognition and hydrolysis by this bacterial xylanase.},
	keywords = {amide-aromatic hydrogen bond, AMINO-ACID, ASSIGNMENTS, BACKBONE AMIDE, beta-glycanase, C-13-LABELED PROTEINS, C-ALPHA, chemical shift index, CHEMICAL-SHIFTS, COUPLING-CONSTANTS, LARGER PROTEINS, NMR, NUCLEAR-MAGNETIC-RESONANCE, SECONDARY STRUCTURE, SIDE-CHAIN RESONANCES, SOLVENT, SUPPRESSION, XYLANASE},
	isbn = {0961-8368},
	url = {<Go to ISI>://A1996UP61700014},
	author = {Plesniak, L. A. and Wakarchuk, W. W. and McIntosh, L. P.}
}
@article {2982,
	title = {SOLVATION DYNAMICS IN ELECTROLYTE-SOLUTIONS},
	journal = {Journal of Chemical Physics},
	volume = {100},
	number = {2},
	year = {1994},
	note = {ISI Document Delivery No.: MT007Times Cited: 33Cited Reference Count: 40},
	month = {Jan},
	pages = {1552-1558},
	type = {Article},
	abstract = {A microscopic theory of the dynamics of ion solvation in electrolyte solutions is given. Consistent with the pure solvent case, the theory predicts a very fast and important inertial relaxation at short times. This is followed by oscillations and an extremely slow long-time decay associated with the formation of an equilibrium {\textquoteright}{\textquoteright}ion atmosphere{\textquoteright}{\textquoteright} about the newly charged particle.},
	keywords = {DIELECTRIC-RELAXATION, INVARIANT EXPANSION, ION, LIQUIDS, MEAN SPHERICAL MODEL, ORNSTEIN-ZERNIKE EQUATION, SIMULATIONS, SOLVENT, SPHERES},
	isbn = {0021-9606},
	url = {<Go to ISI>://A1994MT00700085},
	author = {Chandra, A. and Patey, G. N.}
}
@article {2747,
	title = {MICROSCOPIC THEORY OF SOLVATION DYNAMICS IN DIPOLAR LIQUIDS},
	journal = {Journal of Chemical Physics},
	volume = {99},
	number = {7},
	year = {1993},
	note = {ISI Document Delivery No.: LY603Times Cited: 48Cited Reference Count: 27},
	month = {Oct},
	pages = {4926-4931},
	type = {Article},
	abstract = {A self contained microscopic theory is described for ion solvation dynamics in dipolar fluids. The theory takes account of inertial and non-Markovian effects which are of critical importance for the fast initial phase of the relaxation of the ion-solvent energy. The theory also includes diffusional effects important at long times. The results obtained are shown to be in good agreement with recent computer simulation studies of ions in Stockmayer solvents.},
	keywords = {COMPUTER-SIMULATION, DIELECTRIC-CONSTANT, ELECTROSTATIC SYSTEMS, FLUID, ION SOLVATION, MOLECULAR LIQUIDS, PERIODIC BOUNDARY-CONDITIONS, relaxation, SOLVENT},
	isbn = {0021-9606},
	url = {<Go to ISI>://A1993LY60300004},
	author = {Chandra, A. and Wei, D. Q. and Patey, G. N.}
}
@article {7131,
	title = {ACTIVITY-COEFFICIENTS OF MODEL AQUEOUS-ELECTROLYTE SOLUTIONS - SENSITIVITY TO THE SHORT-RANGE PART OF THE INTERIONIC POTENTIAL},
	journal = {Journal of Chemical Physics},
	volume = {94},
	number = {10},
	year = {1991},
	note = {ISI Document Delivery No.: FL001Times Cited: 7Cited Reference Count: 12},
	month = {May},
	pages = {6782-6783},
	type = {Article},
	abstract = {Activity coefficients are calculated for model aqueous alkali halide solutions. The theoretical results are found to be very sensitive to details of the interionic potential employed and good agreement with experiment is obtained by simply superimposing an additional r-n repulsive interaction upon charged hard sphere potentials. The "best fits" to the experimental data involve interesting changes in the solution structure. In particular, our results suggest that the strong deviations from limiting behavior observed for some alkali halide solutions (e.g., NaCl) are closely associated with structures involving solvent separated as opposed to contact ion pairs.},
	keywords = {EXTENDED RISM EQUATION, FORCE, INFINITE DILUTION, MEAN, MOLECULAR THEORY, SOLVENT},
	isbn = {0021-9606},
	url = {<Go to ISI>://A1991FL00100046},
	author = {Ursenbach, C. P. and Wei, D. Q. and Patey, G. N.}
}
