Previously, we reported a micro magnetic stir-bar mixer driven by an external rotating magnetic field and its rapid mixing performance in polydimethyl-siloxane (PDMS) channels. The PDMS piece with embedded fluid channels were manually aligned to a glass substrate and assembled. In this paper, we report the fabrication and testing results of a micro magnetic stir-bar monolithically integrated in parylene surface-micromachined channels with improved design features, including small tolerance of the stir-bar to channel wall (10 microm). Using of parylene based microchannels with improved design not only provides improved mixing, but also eliminates certain problems associated with PDMS-based channels. For example, porosity of PDMS causes evaporation and absorption of chemicals and thus channels made of PDMS are prone to cross-contamination. We have also demonstrated that the magnetic stir-bar can be used to pump liquid in micro channels.
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http://dx.doi.org/10.1039/b403305a | DOI Listing |
Anal Bioanal Chem
January 2025
GICAPC Research Group, Department of Analytical Chemistry, University of Valencia, 46100, Burjassot, Valencia, Spain.
In this work, a miniaturized and sustainable method for the determination of endocrine-disrupting bisphenols in human serum and urine employing the miniaturized stir bar sorptive dispersive microextraction (mSBSDME) approach has been developed. As bisphenols are conjugated in the human body to their glucorinated and sulfated forms, an enzymolysis employing a commercial mixture of β-glucuronidase and arylsulfatase was carried out prior to the microextraction procedure to determine their total content. A magnetic covalent organic framework (COF) was employed as the sorbent to carry out the extraction of the analytes from the biological matrixes, showing good extraction performance due to its hydrophobic, π-π, and dipole-dipole interactions with the analytes.
View Article and Find Full Text PDFElectrophoresis
November 2024
State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China.
Molecules
October 2024
Faculty of Advanced Technologies and Chemistry, Institute of Chemistry, Military University of Technology, Kaliskiego Str. 2, 00-908 Warsaw, Poland.
The preparation of samples for instrumental analysis is the most essential and time-consuming stage of the entire analytical process; it also has the greatest impact on the analysis results. Concentrating the sample, changing its matrix, and removing interferents are often necessary. Techniques for preparing samples for analysis are constantly being developed and modified to meet new challenges, facilitate work, and enable the determination of analytes in the most comprehensive concentration range possible.
View Article and Find Full Text PDFAnal Chim Acta
November 2024
GICAPC Research Group, Department of Analytical Chemistry, University of Valencia, Burjassot, Valencia, Spain. Electronic address:
Molecules
September 2024
School of Pharmacy, Shujitsu University, Nishigawara, Okayama 703-8516, Japan.
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