Capillary electrophoresis connected to electrospray ionization mass spectrometry is a promising combination to analyze complex biological samples. The use of sheathless electrospray ionization interfaces, such as a porous nanoelectrospray capillary emitter, requires the application of forward flow (either by pressure or electroosmosis) to maintain the electrospray process. The analysis of solute molecules with strong negative charges (e.g., aminopyrenetrisulfonate labeled glycans) necessitates a reversed-polarity capillary electrophoresis separation mode, in which case the electroosmotic flow is counter current, thus pressure assistance is necessary. In this study, we compared the effect of forced convection with and without counter electroosmotic flow on the resulting separation efficiency in capillary electrophoresis based on flow profile simulations by computational fluid dynamics technique and by actual experiments. The efficiencies of the detected peaks were calculated from the resulting electropherograms and found approximately 950 000 plates/m for electrophoresis with counter electroosmotic flow, 20 000 plates/m with pressure only (such as would be in open tubular liquid chromatography), and 480 000 plates/m for electrophoresis with simultaneous counter electroosmotic flow and forward pressure assistance, which validates the simulation data.
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http://dx.doi.org/10.1002/jssc.201701372 | DOI Listing |
J Phys Chem Lett
January 2025
School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, People's Republic of China.
Efficient capture of single-stranded DNA (ssDNA) is crucial for high-throughput sequencing, which influences the speed and accuracy of genetic analysis. Electrophoresis (EP) and electro-osmotic flow (EOF) have a significant impact on the translocation behavior of ssDNA through the nanopore. Experimentally, dynamically tracking these two effects remains challenging, and conventional numerical methods also struggle to capture their dynamic properties in the presence of DNA.
View Article and Find Full Text PDFSoft Matter
January 2025
Department of Mechanical Engineering, Clemson University, Clemson, SC 29634, USA.
Instabilities in the form of periodic or irregular waves at the fluid interface have been demonstrated in microchannel electrokinetic flows with conductivity gradients when the applied electric field is above a threshold value. Most prior studies on electrokinetic instabilities (EKI) are restricted to Newtonian fluids though many of the chemical and biological samples in microfluidic applications exhibit non-Newtonian characteristics. We present in this work an experimental study of the effects of fluid shear thinning on the development of EKI waves through the addition of a small amount of xanthan gum (XG) polymer to both the high- and low-concentration Newtonian buffer solutions.
View Article and Find Full Text PDFSmall Methods
January 2025
Division of Molecular and Medical Genetics, Center for Gene and Cell Therapy, The Institute of Medical Science, The University of Tokyo, Tokyo, 108-8639, Japan.
Achieving safe and efficient gene therapy hinges upon the inspection of genomes enclosed within individual nano-carriers to mitigate potential health risks associated with empty or fragment-filled vectors. Here solid-state nanopore sensing is reported for identifications of intermediate adeno-associated virus (AAV) vectors in liquid. The method exploits the phenomenon of translocation slowdown induced by the viscosity of salt water-organic mixtures.
View Article and Find Full Text PDFSci Rep
December 2024
School of Civil Engineering, Shangqiu Lnstitute of Technology, Shangqiu, 476000, China.
Electroosmosis and surcharge preloading represent two effective soil consolidation methodologies. Their combined application has been proven to be effective in shortening the consolidation period and mitigating the degradation of electroosmotic consolidation performance due to crack generation. In this study, an axisymmetric free-strain consolidation analytical model incorporating a continuous drainage top boundary was established.
View Article and Find Full Text PDFTo investigate the influence of cations on the microstructural characteristics of electrochemical reinforcement in soft clay, a study was conducted using three different cationic salt solutions-NaCl, CaCl₂, and FeCl₃-for grouting treatment. Four sets of indoor experiments were performed to examine the reinforcement mechanism of the electrochemical method. The findings indicate that increasing the valence of injected cations significantly affects the electrochemical reinforcement effect and the soil's microstructural properties.
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