Electrokinetic supercharging (EKS) has been used in the last few years as a powerful tool for separation and on-line preconcentration of different types of analytes. We have developed a valuable modification for EKS system, namely counter-flow EKS (CF-EKS) and applied it for the separation and on-line preconcentration of seven non-steroidal anti-inflammatory drugs (NSAIDs) in water samples. In CF-EKS, a hydrodynamic counter-flow is applied during electrokinetic injection of the analytes within the EKS system. This counter-flow minimises the introduction of the sample matrix into the capillary, allowing longer injections to be performed. Careful choice of the optimum counter-flow as well as the optimum injection voltage allowed the sensitivity to be enhanced by 11,800-fold, giving limits of detection (LODs) of 10.7-47.0 ng/L for the selected NSAIDs. The developed method was validated and then applied for the determination of the studied NSAIDs in drinking water as well as wastewater samples from Hobart city.
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http://dx.doi.org/10.1016/j.chroma.2009.02.014 | DOI Listing |
Anal Methods
April 2024
Department of Chemistry and Biochemistry, Wichita State University, 1845 Fairmount St, Wichita, Kansas 67260, USA.
Residues of glyphosate (GlyP) and its major degradation product, aminomethylphosphonic acid (AMPA), widely exist in the water system and plant products and thus are also present in the bodies of animals and humans. Although no solid evidence has been obtained, the concern about the cancer risk of GlyP is persistent. The measurement of GlyP and AMPA in trace levels is often needed but lacks readily available analytical approaches with detection sensitivity, accuracy and speed.
View Article and Find Full Text PDFBiomed Chromatogr
June 2020
College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou, P.R. China.
Electrokinetic supercharging, a convenient and powerful online preconcentration technique in capillary electrophoresis, was introduced and evaluated for the determination of two alkaloids, berberine and jatrorrhizine, in mice fecal samples for the first time. The method depended on using a bare fused silica capillary (50 cm × 50 μm i.d.
View Article and Find Full Text PDFElectrophoresis
November 2019
Department of Chemistry, University of Michigan, Ann Arbor, MI, USA.
Electrokinetic supercharging (EKS) is known as one of the most effective online electrophoretic preconcentration techniques, though pairing with it with mass spectrometry has presented challenges. Here, EKS is successfully paired with ESI-MS/MS to provide a sensitive and robust method for analysis of biogenic amines in biological samples. Injection parameters including electric field strength and the buffer compositions used for the separation and focusing were investigated to achieve suitable resolution, high sensitivity, and compatibility with ESI-MS.
View Article and Find Full Text PDFElectrophoresis
June 2019
Laboratory for the Analysis of Medicines (LAM), Center for Interdisciplinary Research on Medicines (CIRM), University of Liège, Liège, Belgium.
Parathyroid hormone (PTH) is a common clinical marker whose quantification relies on immunoassays, giving variable results as batch, brand, or target epitope changes. Sheathless CE-ESI-MS, combining CE resolution power and low-flow ESI sensitivity, was applied to the analysis of PTH in its native conformation in the presence of related forms. Fused silica and neutral-coated capillaries were investigated, as well as preconcentration methods such as transient isotachophoresis, field-amplified sample injection (FASI), and electrokinetic supercharging (EKS).
View Article and Find Full Text PDFTalanta
May 2018
Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea. Electronic address:
The World Health Organization (WHO) guideline states that the total arsenic concentration in drinking water must not exceed 10 ppb. However, arsenic toxicity varies significantly, with inorganic arsenic species being more toxic than organic species. Arsenic speciation is therefore important for evaluating the health risks from arsenic-contaminated drinking water.
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