@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 {2184,
	title = {A dopant introduction device for atmospheric pressure photoionization with liquid chromatography/mass spectrometry},
	journal = {Rapid Communications in Mass Spectrometry},
	volume = {22},
	number = {22},
	year = {2008},
	note = {ISI Document Delivery No.: 376QHTimes Cited: 2Cited Reference Count: 16McCulloch, Ross D. Robb, Damon B. Blades, Michael W.},
	month = {Nov},
	pages = {3549-3554},
	type = {Article},
	abstract = {This technical note describes in detail the fabrication, operation and characterization of a pneumatically driven dopant introduction device, with a solvent reservoir capacity of 300 m L. Dopant flow rates and stability for this device are governed by the simple regulation of gas pressure rather than the progression of a stepper motor and syringe diameter, as is the case for typical infusion pumps. The device has the potential to provide days or even weeks of continuous, uninterrupted dopant flow at rates commonly adopted for atmospheric pressure photoionization (APPI) experiments without the need to replenish the dopant supply. Although not a refined instrumental design, this device was developed as an alternative cost-effective means of introducing stable dopant flow to an APPI source. The device was designed such that all components would be commercially available and easily procurable from common scientific part vendors. Figures and suggested part numbers are provided to allow those interested to fabricate similar devices to suit their individual experimental needs. Device characterization was performed while monitoring such factors as flow rate calibration, overall flow stability and reproducibility. In addition, a standard mixture of three polycyclic aromatic hydrocarbons was employed as a model sample for a typical reversed-phase liquid chromatography/ atmospheric pressure photoionization mass spectrometry (LC/APPI-MS) application in order to demonstrate device performance. Copyright (c) 2008 John Wiley \& Sons, Ltd.},
	keywords = {DA-APPI, IONIZATION, LC/MS, MASS-SPECTROMETRY, NONPOLAR COMPOUNDS},
	isbn = {0951-4198},
	url = {<Go to ISI>://000261197600011},
	author = {McCulloch, R. D. and Robb, D. B. and Blades, M. W.}
}
