posted on 2023-05-27, 11:53authored byWuethrich, A
Traditional sample preparation requires substantial resources and time, both adversely affecting the economical and ecological accounts of an analytical workflow. To address the dearth of greenness, this work used field-enhanced and electrokinetic sample injection from capillary electrophoresis (CE) for off-line sample preparation. This approach, referred to as electrophoretic concentration (EC) and simultaneous EC and separation (SECS), relies on the use of an electric field to transfer charged analytes from a mL-volume of aqueous sample to 20 ˜í¬¿L of acceptor electrolyte immobilised in a micropipette. The use of a conductive hydrogel to facilitate a zero net-flow inside a fused silica capillary is described and then explored for EC of charged analytes. The hydrogel was crucial to the success of EC, because it supported voltage application and retained the acceptor electrolyte in the micropipette. Anionic dyes and pollutants from drinking water as well as cationic drugs from wastewater were concentrated in less than 50 min and sensitive analysis by CE was achieved. The EC setup was then modified for SECS and implemented on an eight channel device to increase the sample throughput. Herbicides fortified in river water and beer samples were used to study SECS in combination with chromatographic and electrophoretic separation employing UV and mass spectrometric detection. Analyte enrichments of up to a factor of 337 in less than 45 min were achieved which enabled low ng/mL detection. Compared to solid-phase extraction, SECS reduced the sample preparation time by 94% and resource consumption by 99%. EC and SECS in combination with stacking-CE showed potential for trace analysis and all the SECS and EC acceptor electrolytes were directly compatible for analytical separation without the need for time-consuming steps. EC and SECS were organic solvent-free, rapid and simple sample preparations which were complying with the principles of Green Analytical Chemistry.
Copyright 2016 the author Chapter 1 appears to be the equivalent of a post-print version of an article published as: Wuethrich, A., Haddad, P. R., Quirino, J. P., 2016. The electric field : an emerging driver in sample preparation. TrAC Trends in Analytical Chemistry, 80, 604-611 Chapter 2 appears to be the equivalent of a post-print version of an article published as: Wuethrich, A., Haddad, P. R., Quirino, J. P., 2014. Zero net-flow in capillary electrophoresis using acrylamide based hydrogel, Analyst, 139, 3722-3726 Chapter 3 appears to be the equivalent of a post-print version of an article published as: Wuethrich, A., Haddad, P. R., Quirino, J. P., 2014. Off-line sample preparation by electrophoretic concentration using a micropipette and hydrogel, Journal of Chromatography A, 1369, 186-190 Chapter 4 appears to be the equivalent of a post-print version of an article published as: Wuethrich, A., Haddad, P. R., Quirino, J. P., 2015. Electrophoretic concentration and sweeping-micellar electrokinetic chromatography analysis of cationic drugs in water samples, 1401, 84-88 Chapter 5 appears to be the equivalent of the accepted manuscript version of a published work that appeared in final form in Analytical chemistry, copyright Copyright American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://dx.doi.org/10.1021/ac504765h Chapter 6 appears to be the equivalent of the peer reviewed version of the following article: Wuethrich, A., Haddad, P. R., Quirino, J. P., 2016. Electrophoresis, 37(9), 10122-1128, which has been published in final form athttps://doi.org/10.1002/elps.201600050 This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.