@article {2432,
	title = {A new broadly tunable (7.4-10.2 eV) laser based VUV light source and its first application to aerosol mass spectrometry},
	journal = {International Journal of Mass Spectrometry},
	volume = {279},
	number = {2-3},
	year = {2009},
	note = {ISI Document Delivery No.: 399TJTimes Cited: 10Cited Reference Count: 78Hanna, S. J. Campuzano-Jost, P. Simpson, E. A. Robb, D. B. Burak, I. Blades, M. W. Hepburn, J. W. Bertram, A. K.},
	month = {Jan},
	pages = {134-146},
	type = {Article},
	abstract = {A laser based vacuum ultraviolet (VUV) light source using resonance enhanced four wave difference mixing in xenon gas was developed for near threshold ionization of organics in atmospheric aerosol particles. The source delivers high intensity pulses of VUV light (in the range of 10(10) to 10(13) photons/pulse depending on wavelength, 5 ns FWHM) with a continuously tunable wavelength from 122 nm (10.2 eV) to 168 nm (7.4 eV). The setup allows for tight (< 1 mm(2)) and precise focusing (mu rad pointing angle adjustability), attributes required for single particle detection. The generated VUV is separated from the pump wavelengths by a custom monochromator which ensures high spectral purity and minimizes absorptive losses. The performance of the source was characterized using organic molecules in the gas phase and optimal working conditions are reported. In the gas phase measurements, photoionization efficiency (PIE) curves were collected for seven different organic species with ionization energies spanning the full wavelength range of the VUV source. The measured appearance energies are very close to the literature values of the ionization energies for all seven species. The effectiveness of the source for single particle studies was demonstrated by analysis of individual caffeine aerosols vaporized by a pulsed CO2 laser in an ion trap mass spectrometer. Mass spectra from single particles down to 300 nm in diameter were collected. Excellent signal to noise characteristics for these small particles give a caffeine detection limit of 8 x 10(5) molecules which is equivalent to a single 75 nm aerosol, or approximately 1.5\% of a 300 nm particle. The appearance energy of caffeine originating from the aerosol was also measured and found to be 7.91 +/- 0.05 eV, in good agreement with literature values. (C) 2008 Elsevier B.V. All rights reserved.},
	keywords = {Aerosol mass spectrometry, analysis, CROSS-SECTIONS, EFFICIENCY, FUEL-RICH FLAMES, GENERATING PARTICLE BEAMS, ION-TRAP, ONLINE, ORGANIC-COMPOUNDS, PARTICULATE MATTER, PHOTOIONIZATION, SINGLE-PHOTON IONIZATION, SURFACE-ANALYSIS, Vacuum ultraviolet light, VACUUM-ULTRAVIOLET PHOTOIONIZATION},
	isbn = {1387-3806},
	url = {<Go to ISI>://000262821900012},
	author = {Hanna, S. J. and Campuzano-Jost, P. and Simpson, E. A. and Robb, D. B. and Burak, I. and Blades, M. W. and Hepburn, J. W. and Bertram, A. K.}
}
@article {1389,
	title = {Behavior of interacting species in capillary electrophoresis described by mass transfer equation},
	journal = {Analytical Chemistry},
	volume = {78},
	number = {6},
	year = {2006},
	note = {ISI Document Delivery No.: 025ZYTimes Cited: 9Cited Reference Count: 30},
	month = {Mar},
	pages = {1832-1840},
	type = {Article},
	abstract = {Affinity capillary electrophoresis (ACE) has been used to estimate thermodynamic constants of binding interactions with linear or nonlinear regression methods. The accuracy of this approach relies heavily on the binding interaction mechanism, which is controlled by both the nature of the interaction and the experimental conditions. The development of a highly efficient computer-simulated ACE system makes it possible to demonstrate the detailed behavior of any interacting species of a given interaction under any conditions. The order of the mobilities of the complex and the two binding species in their free forms is a key factor to determine what molecules in what locations of the column are involved in the interaction, and the peak shape resulting from such interactions, of a given ACE experiment. In this paper and the supporting materials, 18 scenarios in 6 different combinations of migration orders of the free analyte, free additive, and complex formed are studied by a computer simulation program based on the mass transfer equation. From the study of these situations, we conclude high additive concentration (ensuring high capacity factor) and low analyte concentration (ensuring fast fill-in of the free additive in the analyte plug) are crucial for obtaining accurate results when using the regression methods. On the other hand, the approach to estimate binding constants with computer simulation can be much more accurate as long as accurate and efficient simulation models can be developed, especially when the ratio of the additive and analyte concentrations is not large enough.},
	keywords = {BINDING CONSTANTS, CHROMATOGRAPHY, DISPERSION, EFFICIENCY, ERROR PROPAGATION, MONTE-CARLO-SIMULATION, pressure, RECTANGULAR HYPERBOLAE, SEPARATIONS, ZONE-ELECTROPHORESIS},
	isbn = {0003-2700},
	url = {<Go to ISI>://000236307700015},
	author = {Fang, N. and Chen, D. D. Y.}
}
@article {443,
	title = {Univalent salts as modifiers in micellar capillary electrophoresis},
	journal = {Electrophoresis},
	volume = {23},
	number = {12},
	year = {2002},
	note = {ISI Document Delivery No.: 573XDTimes Cited: 11Cited Reference Count: 23},
	month = {Jun},
	pages = {1912-1920},
	type = {Article},
	abstract = {The influence of three univalent salts (LiCl, and RbCl) on the separation of amino acids labelled with 3-(4-carboxybenzoyl)-quinoline-2-carboxaldehyde (CBQCA) in micellar capillary electrophoresis has been studied. Capacity factors for a series of eight CBQCA-labelled amino acids in a sodium dodecyl sulfate (SDS) micellar system containing different concentrations of salt were measured and were found to be related to both the hydrodynamic radius of the salt counter-ion (Li+, Na+, Rb+) and the relative hydrophobicity of the amino acid. Affinities of the analytes for the micelles were generally observed to decrease as the salt concentration in the background electrolyte was increased from 10 to 50 mM. This decrease in affinity was greatest in the presence of the salt counter-ion with the smallest hydrodynamic radius and is primarily due to an increased resistance to mass transfer. Furthermore, interaction of hydrophobic analytes with the micelles is greater than that of hydrophilic analytes at all salt concentrations due to the greater strength of the hydrophobic interactions and this effect is also enhanced in the presence of a smaller counter-ion. No negative effects due to Joule heating or electromigrative dispersion were observed for low to moderate concentrations of salt, which suggests that the use of simple univalent salts to modify analyte/micelle affinities can be a practical method for improving the separation of complex mixtures.},
	keywords = {amino acids, AMMONIUM-SALTS, COUNTER-ION, EFFICIENCY, ELECTROKINETIC CHROMATOGRAPHY, FLUORESCENCE, micellar capillary electrophoresis, MIGRATION BEHAVIOR, modifiers, RESOLUTION, salt, SDS, SELECTIVITY, SEPARATION},
	isbn = {0173-0835},
	url = {<Go to ISI>://000176857000019},
	author = {McLaren, D. G. and Boulat, O. and Chen, D. D. Y.}
}
