An analytical method is described for determining the residues of coplanar PCB congeners exhibiting toxicological relevance, in foods of animal origin and human milk. The unsophisticated procedure, convenient for routine analyses, includes extraction and saponification of lipids, isolation of the unsaponifiable matter and its cleanup on a small silica gel column, fractionation using HPLC on a special carbon column and gas-chromatographic analysis with capillary columns and electron capture detection (ECD).
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http://dx.doi.org/10.1007/BF01202511 | DOI Listing |
Acta Crystallogr E Crystallogr Commun
January 2025
Department of Chemistry, Bahir Dar University, PO Box 79, Bahir Dar, Ethiopia.
The asymmetric unit of the title compound, CHN·Br·CFI, contains one 2,2,6,6 tetra-methyl-piperidine-1-ium cation, one 1,2,3,4-tetra-fluoro-5,6-di-iodo-benzene mol-ecule, and one uncoordinated bromide anion. In the crystal, the bromide anions link the 2,2,6,6-tetra-methyl-piperidine mol-ecules by inter-molecular C-H⋯Br and N-H⋯Br hydrogen bonds, leading to dimers, with the coplanar 1,2,3,4-tetra-fluoro-5,6-di-iodo-benzene mol-ecules filling the space between them. There is a π-π interaction between the almost parallel benzene rings [dihedral angle = 10.
View Article and Find Full Text PDFSensors (Basel)
December 2024
Department of Electrical and Computer Engineering, University of Manitoba, Winnipeg, MB R3T 5V6, Canada.
This paper presents a lens-free imaging approach utilizing an array of light sources, capable of measuring the dielectric properties of many particles simultaneously. This method employs coplanar electrodes to induce velocity changes in flowing particles through dielectrophoretic forces, allowing the inference of individual particle properties from differential velocity changes. Both positive and negative forces are detectable.
View Article and Find Full Text PDFBiosensors (Basel)
November 2024
Department of Electrical and Computer Engineering, University of Manitoba, Winnipeg, MB R3T 5V6, Canada.
In this paper, we present a microfluidic flow cytometer for simultaneous imaging and dielectric characterization of individual biological cells within a flow. Utilizing a combination of dielectrophoresis (DEP) and high-speed imaging, this system offers a dual-modality approach to analyze both cell morphology and dielectric properties, enhancing the ability to analyze, characterize, and discriminate cells in a heterogeneous population. A high-speed camera is used to capture images of and track multiple cells in real-time as they flow through a microfluidic channel.
View Article and Find Full Text PDFMethodsX
December 2024
Department of Electrical Engineering, College of Engineering Al-Hussein Bin Talal, University, Ma'an 71111, Jordan.
Coplanar waveguide (CPW) transmission lines are valued for their planar design, low radiation, and minimized signal loss, but controlling their characteristic impedance remains a challenge. This study employs the Taguchi method, a statistical approach, to optimize the characteristic impedance by adjusting eight control factors: track width, track thickness, gap width, dielectric height, backplane thickness, conductor material conductivity, dielectric conductivity, and operational frequency. The analysis evaluates these factors across three levels to find optimal conditions, with dielectric height and track width identified as most influential.
View Article and Find Full Text PDFAppl Phys Lett
January 2024
Communications Technology Laboratory, National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA.
Fused silica has become an interesting alternative to silicon for millimeter-wave (mmWave) applications. Unfortunately, there are a few reports on the measurement of fused silica's permittivity above 110 GHz that use electrical rather than optical methods. Given that mmWave applications use electrical circuits, additional electrical data would be useful to industry.
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