A preconcentration approach for CE-MS using counterflow-assisted electrokinetic injection was proposed. The proposed preconcentration method was based on a counterflow-compatible sheathless interface. The interface was fabricated using a capillary-assembled PDMS microdevice that allowed the application of a counterflow and provided liquid-film electrical conduction. During electrokinetic injection, a hydrodynamic counterflow was introduced into the separation capillary to retard the movement of the stacking boundary to the CE outlet. Accordingly, a long injection time was achieved without a loss of CE separation. With the use of reverse polarity mode and a dynamic polybrene-coated separation capillary (filled with a 1% formic acid solution), a counterflow-assisted electrokinetic injection of peptide samples (in a aqueous solution containing 1% ammonia and 50% methanol) for 10 min provided a sensitivity enhancement of 750-1480 and a detection limit of 20 pM for the five peptide standards. The proposed technique was applied to the analysis of low nanomolar concentrations myoglobin tryptic peptides.
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http://dx.doi.org/10.1002/elps.201300446 | DOI Listing |
J Chromatogr A
January 2025
State Key Laboratory of Component-based Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, China; Tianjin Key Laboratory of Phytochemistry and Pharmaceutical Analysis, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, China. Electronic address:
A rapid and sensitive enrichment technique, field enhanced sample injection-dynamic pH junction-sweeping (FESI-DypH-sweeping) was successfully developed for the simultaneous separation and concentration of alkaloids and stereoisomers of Uncariae ramulus cum uncis (UR) by cyclodextrin electrokinetic chromatography (CDEKC) with diode array detection system. The sample was prepared in a low-conductivity (FESI), low-pH (DypH) sample matrix (4 mM phosphate buffer, 3% methanol, pH=3), and the background electrolyte (BGE) consisted of a high-conductivity, high-pH buffer (40 mM phosphate buffer, pH 7.0, 8 mg/mL carboxymethyl-β-cyclodextrin, and 30% methanol).
View Article and Find Full Text PDFTalanta
March 2025
Ottawa-Carleton Chemistry Institute, Department of Chemistry Carleton University, Ottawa, ON, K1S 5B6, Canada. Electronic address:
J Hazard Mater
December 2024
State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Centre for Environmental Risk Management & Remediation of Soil & Groundwater, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China. Electronic address:
Herein, we proposed and demonstrated a novel approach of combining electrokinetics (EK)-assisted delivery of persulfate (PS) and ultrasound-induced thermal activation of PS and release of heavy metals, to synchronously remove organic pollutants and heavy metals from soil. Results showed that in tested soil, the mass transfer efficiency of PS induced by electromigration was approximately 3.36 times that by electroosmotic flow and 1416 times that by diffusion.
View Article and Find Full Text PDFActa Pharm
September 2024
Faculty of Pharmacy, Chair of Pharmaceutical Biology, University of Ljubljana, 1000 Ljubljana, Slovenia.
A new micellar electrokinetic capillary chromatographic (MEKC) method has been developed and optimized for simultaneous quantitation of doxorubicin (Dox) and fullerenol (Frl) in rat serum. The separation was carried out in a capillary (48.5-40 cm to the detector - 50 µm id fused-silica capillary with bubble cell, 150 µm) at an applied voltage of 25 kV and temperature of 25 °C.
View Article and Find Full Text PDFToxics
August 2024
School of Transportation and Civil Engineering, Nantong University, Nantong 226019, China.
Electrokinetic remediation (EKR) has shown great potential for the remediation of in situ contaminated soils. For heavy metal-contaminated soft clay with high moisture content and low permeability, an electrokinetic remediation method with electrolytes placed above the ground surface is used to avoid issues such as electrolyte leakage and secondary contamination that may arise from directly injecting electrolytes into the soil. In this context, using this novel experimental device, a set of citric acid (CA)-enhanced EKR tests were conducted to investigate the optimal design parameters for Cu- and Zn-contaminated soft clay.
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