Christopher P. Palmer

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Name: Palmer, Christopher
Organization: University of Montana , USA
Department: Department of Chemistry
Title: Professor(PhD)

TOPICS

Co-reporter:Christopher P. Palmer, Emily F. Hilder, Joselito P. Quirino and Paul R. Haddad
Analytical Chemistry 2010 Volume 82(Issue 10) pp:4046
Publication Date(Web):April 19, 2010
DOI:10.1021/ac902922u
The utility of novel latex nanoparticles as pseudostationary phases for electrokinetic chromatography with UV and mass spectrometric detection is demonstrated. The nanoparticles are synthesized using ab initio RAFT (reversible addition−fragmentation chain transfer) in emulsion polymerization, which yields small (63 nm) particles with a narrow size distribution, a hydrophobic core, and an ionic shell. The nanoparticles are shown to provide efficient and selective separations, with retention and separation selectivity dominated by hydrophobic interactions. The nanoparticles are highly retentive, such that they are effective at relatively low concentrations. Addition of the nanoparticles to the background electrolyte at these concentrations has a minor effect on the noise with UV detection, no measurable effect on the separation current, and minor effects on analyte ionization efficiency during electrospray ionization. The nanoparticles do not cause fouling or degradation of the electrospray−mass spectrometer interface even after several weeks of use. The combination of online sample preconcentration via sweeping and selective mass spectrometric detection yields low detection limits (10−16 ppb), particularly for more hydrophobic compounds.
Co-reporter:Megan A Bergauff, Tony J Ward, Curtis W Noonan, Christopher T Migliaccio, Christopher D Simpson, Ashley R Evanoski and Christopher P Palmer
Journal of Exposure Science and Environmental Epidemiology 2010 20(4) pp:385-392
Publication Date(Web):August 26, 2009
DOI:10.1038/jes.2009.46
Urinary levoglucosan was investigated as a potential biomarker of wood smoke exposure in two different controlled experimental settings. Nine subjects were exposed to smoke from a campfire in a controlled setting, and four were exposed to smoke from an older-model wood stove. All subjects were asked to provide urine samples before and after exposure, and to wear personal particulate matter with a diameter of ≤2.5 μm (PM2.5) monitors during exposure. Urinary levoglucosan measurements from both studies showed no consistent response to the smoke exposure. A third experiment was conducted to assess the contribution of dietary factors to urinary levoglucosan levels. Nine subjects were asked to consume caramel and provide urine samples before and after consumption. Urinary levoglucosan levels increased within 2 h of caramel consumption and returned to pre-exposure levels within 24 h. These studies suggest that diet is a major factor in determining urinary levoglucosan levels and that recent dietary history needs to be taken into account for future work involving levoglucosan as a biomarker of wood smoke exposure.
Co-reporter:Jesse J. Stine
Journal of Separation Science 2009 Volume 32( Issue 3) pp:446-456
Publication Date(Web):
DOI:10.1002/jssc.200800533

Abstract

Synthetic chemistry originally developed for the manufacture of chemically stable silica polyamine composites was adapted for the modification of fused silica capillaries for application in CE. Polyethyleneimine (PEI) and polyallylamine (PAA) were covalently bonded to the interior surface of fused silica capillaries utilizing 3-chloropropyltrichlorosilane (CPTCS) or 3-glycidoxypropyl-trimethoxysilane (GPTMS) to anchor the polymers to the surface. The surface-bound polymers were subsequently quaternized using methyl iodide (MeI). The resulting modified capillaries were studied using CE, and were shown to provide reproducible, stable, and robust anodic EOF throughout the pH range of 2–10. Surface modifications utilizing CPTCS could be rinsed with up to 6 M HCL or 1 M NaOH without significant loss of surface modifier. The utility of the modified capillaries for the separation of simple anions and cations was demonstrated.

Co-reporter:Christopher P. Palmer
Journal of Separation Science 2008 Volume 31( Issue 5) pp:783-793
Publication Date(Web):
DOI:10.1002/jssc.200700524

Abstract

Recent research and development efforts concerning polymeric pseudostationary phases (PSPs) for electrokinetic chromatography are reviewed. The introduction of new materials, characterization of structural effects on performance and selectivity, applications, and the use of polymeric PSPs with mass spectrometric detection are considered. Very interesting results concerning the effects of polymer structure have been reported. Significant developments have also been reported in the development of novel applications of polymeric PSPs, particularly for sample preconcentration using micellar affinity gradient focusing. The use of mass spectrometric detection with electrokinetic chromatography has seen significant development, and recent reports indicate that this is a robust and sensitive approach.

Co-reporter:Erika Rauk, Anton Kotzev, André Laschewsky, Christopher P. Palmer
Journal of Chromatography A 2006 Volume 1106(1–2) pp:29-35
Publication Date(Web):17 February 2006
DOI:10.1016/j.chroma.2005.07.114
Separation selectivity in electrokinetic chromatography (EKC) is directly affected by the chemistry and solvent characteristics of the pseudostationary phase (PSP). The chemical selectivity of micellar PSPs has been previously demonstrated to vary significantly between anionic and cationic surfactants as well as between hydrocarbon and fluorocarbon surfactants. Polymeric PSPs have also been demonstrated to provide unique selectivity. In the current study, four cationic polymeric pseudo-stationary phases, two of which have perfluorinated pendant groups, are introduced and characterized as PSPs in EKC. Their performance and selectivity is compared to conventional micellar PSPs with similar structure. The solvation characteristics and selectivity of the four polymers most closely resemble those observed for cationic micelles. The polymers are all more cohesive and more polar than their hydrocarbon micellar counterparts. The fluorocarbon PSPs did show preferential interaction with fluorocarbon solutes, were somewhat more cohesive, and were stronger hydrogen bond donors. However, the presence of fluorocarbon moieties did not have as dramatic an effect on selectivity as was observed and published previously for fluorocarbon micelles. This may result from the selectivity being dominated by the presence of the cationic head groups or from the fluorocarbon character of the pendant groups being moderated by the presence of hydrocarbon functionality on the polymer backbones.
TRIMETHYL-[3-(PROP-2-ENOYLAMINO)PROPYL]AZANIUM
TRIMETHYL(2-PROP-2-ENOYLOXYETHYL)AZANIUM
1,2-dimyristoyl-sn-glycero-3-phospho-choline monohydrate
SMA 1440-H RESIN
7-oxodehydroabietic acid
Alprenolol
TETRABUTYLAZANIUM
pimara-8,15-dien-18-oic acid
1-Phenanthrenecarboxylicacid, 7-ethenyl-1,2,3,4,4a,4b,5,6,7,8,10,10a-dodecahydro-1,4a,7-trimethyl-,(1R,4aR,4bS,7S,10aR)-