A new glass/PDMS hybrid chip for contactless conductivity detection is reported. This chip consists of a glass substrate with microchannels and a PDMS cover sheet embedded with a small integrated electrode plate. In the region of detection, electrodes are insulated from the microchannel by a formed PDMS membrane about 100 μm in thickness. Without any modification, this glass/PDMS chip is suitable for contactless conductivity detection with good properties, such as excellent heat-dissipation, stable electroosmotic flow, high separation efficiency, satisfactory sensitivity, simple construction and high degree of integration. Its feasibility and performance had been demonstrated by analyzing inorganic ions and amino acids in mixtures, and alkaloids in traditional Chinese medicine. The limits of detection reached micromole per liter (μmol L−1) levels. This microchip could be promising for mass production due to its stability, reproducibility, ease of fabrication and low cost.
We present a program for computing symmetric quadrature rules on triangles and tetrahedra. A set of rules are obtained by using this program. Quadrature rules up to order 21 on triangles and up to order 14 on tetrahedra have been obtained which are useful for use in finite element computations. All rules presented here have positive weights with points lying within the integration domain. 相似文献
Electrochemical oxidation of graphite anode in deionized water at galvanostatic mode is investigated. It is found that mellitic acid and graphite oxide colloid (>20 nm) are coexisted as main products, as identified by XRD and TEM, FTIR and XPS. They can be separated successfully through several procedures. A few amounts of graphene and graphene rolls are also appeared as co-products. 相似文献
The nitration of aromatic compounds can be carried out in the presence of perfluorinated rare earth metal catalyst without halogenated organic solvent. 相似文献