@article{miller_shea_khaledi_2000, title={Separation of acidic solutes by nonaqueous capillary electrophoresis in acetonitrile-based media - Combined effects of deprotonation and heteroconjugation}, volume={888}, ISSN={["0021-9673"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0034604766&partnerID=MN8TOARS}, DOI={10.1016/S0021-9673(00)00467-2}, abstractNote={Nonaqueous capillary electrophoresis (NACE) is a chemical separation technique that has grown in popularity over the past few years. In this report, we focus on the combination of heteroconjugation and deprotonation in the NACE separation of phenols using acetonitrile (ACN) as the buffer solvent. By preparing various dilute buffers consisting of carboxylic acids and tetrabutylammonium hydroxide in ACN, selectivity may be manipulated based on a solute's dissociation constant as well as its ability to form heterogeneous ions with the buffer components. ACN's low viscosity, coupled with its ability to allow for heteroconjugation, often leads to rapid and efficient separations that are not possible in aqueous media. In this report, equations are derived showing the dependence of mobility on various factors, including the pKa of the analyte, the pH and concentration of the buffer, and the analyte-buffer heteroconjugation constant (Kf). The validity of these equations is tested as several nitrophenols are separated at different pH values and concentrations. Using nonlinear regression, the Kf values for the heteroconjugate formation between the nitrophenols and several carboxylate anions are calculated. Also presented in this report are the NACE separations of the 19 chlorophenol congeners and the 11 priority pollutant phenols (used in US Environmental Protection Agency methods 604, 625/1625 and 8270B).}, number={1-2}, journal={JOURNAL OF CHROMATOGRAPHY A}, author={Miller, JL and Shea, D and Khaledi, MG}, year={2000}, month={Aug}, pages={251–266} }
 @inbook{miller_khaledi_1998, title={Nonaqueous capillary electrophoresis}, volume={146}, ISBN={0471148512}, booktitle={High-performance capillary electrophoresis: theory, techniques, and applications}, publisher={New York: John Wiley & Sons}, author={Miller, J. L. and Khaledi, M. G.}, year={1998}, pages={525–555} }
 @article{miller_khaledi_shea_1998, title={Separation of hydrophobic solutes by nonaqueous capillary electrophoresis through dipolar and charge-transfer interactions with pyrylium salts}, volume={10}, ISSN={["1040-7685"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0001258994&partnerID=MN8TOARS}, DOI={10.1002/(SICI)1520-667X(1998)10:8<681::AID-MCS7>3.0.CO;2-6}, abstractNote={In this study, the use of pyrylium salts for the separation of uncharged hydrophobic solutes in nonaqueous capillary electrophoresis (NACE) is examined. In an aprotic solvent such as acetonitrile, large polarizable compounds selectively interact with planar organic cations, thereby facilitating the analysis of solutes that have low solubilities in aqueous or mixed solvents. Presented in this article are the separations of polycyclic aromatic hydrocarbons (PAHs) that were achieved through dipolar and charge-transfer interactions with various substituted pyrylium cations. It was found that the number of rings contained in the PAH molecule, the presence of functional groups on the molecule, the concentration of the pyrylium cation, and the number of phenyl substituents on the pyrylium ring affected the electrophoretic mobility of the solute–cation complex. © 1998 John Wiley & Sons, Inc. J Micro Sep 10: 681–685, 1998}, number={8}, journal={JOURNAL OF MICROCOLUMN SEPARATIONS}, author={Miller, JL and Khaledi, MG and Shea, D}, year={1998}, pages={681–685} }
 @article{miller_wollum_weber_1997, title={Degradation of carbon-14-atrazine and carbon-14-metolachlor in soil from four depths}, volume={26}, ISSN={["1537-2537"]}, DOI={10.2134/jeq1997.00472425002600030007x}, abstractNote={Degradation of 14 C-atrazine [2-chloro-4-ethylamino-6-isopropylamino-s-triazine] and 14 C-metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamide] was monitored for 6 and 2 mo, respectively, using sterile and nonsterile soil microcosms. Both chemical and biological degradation were observed for atrazine, metolachlor degraded only biologically. The calculated half-life of atrazine was 3.6 wk in nonsterile surface samples (0-5 cm). At the surface, after 22 wk, bound residues accounted for almost 60% of the recovered radioactivity while 36% was recovered as 14 CO 2 , indicating significant cleavage of the triazine ring. For sterilized surface samples, atrazine degraded chemically with bound residues accounting for 63% of the recovered label and had a calculated half-life of 6.2 wk. Degradation and binding were somewhat lower in soil samples from 20 to 25 cm and deeper subsurface samples (45 and 75 cm) showed almost no degradation and very little binding. Metolachlor degraded only in the surface nonsterile samples; no degradation was observed in subsurface samples or in sterile samples from any depth. Bound residues occurred in high amounts in the surface soil (31%) but declined rapidly with depth, indicating that organic matter is the primary binding site for metolachlor. Very little 14 CO 2 (<1.6%) was produced from metolachlor in any sample. This study showed that both herbicides degraded slower and sorbed less to the soil with increasing soil depth, especially below 25 em. Quantifying degradation rates of agricultural chemicals in the vadose zone is important for predicting and preventing groundwater contamination as well as for successful implementation of in-situ bioremediation of contaminated subsoils.}, number={3}, journal={JOURNAL OF ENVIRONMENTAL QUALITY}, author={Miller, JL and Wollum, AG and Weber, JB}, year={1997}, pages={633–638} }
 @article{miller_khaledi_shea_1997, title={Separation of polycyclic aromatic hydrocarbons by nonaqueous capillary electrophoresis using charge-transfer complexation with planar organic cations}, volume={69}, ISSN={["0003-2700"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0031569134&partnerID=MN8TOARS}, DOI={10.1021/ac960734n}, abstractNote={In this study, we examine the use of charge-transfer interactions between polycyclic aromatic hydrocarbons (PAHs) and planar organic cations in nonaqueous capillary electrophoresis. Since the separations are performed in a purely nonaqueous medium, this method also facilitates the analysis of solutes that have low solubilities in aqueous or mixed media. Presented in this study are the separations of PAHs as well as the quantitative structure-migration relationships that assisted in achieving a better understanding of the forces through which the PAH molecules interact with the acceptor cation. It was found that, in addition to charge-transfer interactions, electrostatic and dispersive forces play an important role in PAH-cation binding.}, number={6}, journal={ANALYTICAL CHEMISTRY}, author={Miller, JL and Khaledi, MG and Shea, D}, year={1997}, month={Mar}, pages={1223–1229} }
 @article{miller_wollum_weber_1997, title={Sterile and nonsterile degradation of carbon-14-primisulfuron in soil from four depths}, volume={26}, ISSN={["0047-2425"]}, DOI={10.2134/jeq1997.00472425002600020015x}, abstractNote={AbstractThe degradation of 14C‐primisulfuron (2‐[[[[[4,6‐bis(difluoromethoxy)‐2‐pyrimidinyl]amino]carbonyl]amino]sulfonyl] benzoic acid) was monitored for 2 mo using soil microcosms under sterile and nonsterile conditions. Both chemical and biological degradation was detected. The half‐life was 2.1 wk for nonsterile samples from 0 to 5 cm, and 3.4 wk for nonsterile samples from 20 to 25 cm. After 7 wk, bound residues accounted for 48 and 27% of the recovered radioactivity in these samples, respectively. For sterile samples from the same depths, the half‐life was >7 wk and bound residues accounted for 7% of the recovered radiolabel. Disappearance and bound residue formation of primisulfuron were similar for both sterile and nonsterile samples from deeper in the profile (45–75 cm) indicating little biological degradation occurred in these subsurface samples. Chemical and microbial degradation of primisulfuron appeared to differ; the same metabolites were produced but at different times and in different amounts. Very little 14CO2 (<3%) was produced from any sample. These results indicate that initial hydrolyzation of the sulfonylurea bridge occurs both chemically and biologically, but does not occur readily in the subsoil. This may have implications for the prevention of groundwater contamination and for the bioremediation of contaminated soils.}, number={2}, journal={JOURNAL OF ENVIRONMENTAL QUALITY}, author={Miller, JL and Wollum, AG and Weber, JB}, year={1997}, pages={440–445} }