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61.
In this paper, a flow-through potentiometric microsensor is described which is based on semi-permeable tubing. The ion selective
electrodes proposed are of the liquid membrane type in which a dialysis tube captures the ion selective cocktail. Ion selective
sensors and a reference electrode based on the same design were constructed by guiding a 0.3 mm diameter dialysis tube through
a cavity precision machined in Perspex?. Commercia lly available ionophore or ion-exchanger cocktails were applied to provide
ion selectivity whilst a saturated KCl solution was used in the reference electrode. A number of flow-through microsensors
selective to different ions (Na, K, Li, pH) were constructed and tested. Each showed good performance in a broad range of
concentrations. Advantages of the proposed approach are the generic technology to make sensors with incorporate d reference
electrodes, capable of measuring a wide variety of analytes for which cocktails are readily available and the fact that sub-microliter
amounts of sample can be measured. Secondly, in comparison to other sensors applied in microchannels, the impedance of the
flow-through sensor is much smaller because of the relatively large sensing surface formed by the tube wall. Moreover, the
use of dialysis tubing enables easy integration with a so-called microdialysis probe for in-vivo sampling of the blood stream
or subcutaneous tissue.
Received December 6, 1999. Revision March 24, 2000. 相似文献
62.
Wouter Zijl 《国际流体数值方法杂志》1988,8(5):599-612
A formulation based on three scalar functions or potentials is applied to analyse the Navier-Stokes and Boussinesq equations in three dimensions. In this formulation an explicit expression for the pressure exists, the so-called generalized Bernoulli equation. Therefore the scalar functions formulation may be considered as a generalization of the well-known potential flow and Bernoulli theory for irrotational fluid motion. The many advantages of this formulation applied to three-dimensional Navier-Stokes and Boussinesq flow will be discussed, and a numerical example is given as an illustration. 相似文献
63.
Martin Berkheij Claudia Sewing Jan Willem Terpstra Wouter I. Iwema Bakker Jan H. van Maarseveen 《Tetrahedron letters》2005,46(14):2369-2371
A novel efficient synthetic route towards the pharmaceutically relevant 2-substituted piperazine class is described. The key step involves α-lithiation of N-Boc piperazines, followed by reaction with several electrophiles. To obtain high yields, in some cases transmetallation to copper after the lithiation step is required. 相似文献
64.
The development of a miniaturized ammonia sensor made using microsystem technology is described. Gas is sampled in a sampler comprising two opposite channels separated by a gas permeable, water repellent polypropylene membrane. Subsequently, the acid sample solution is pumped into a selector where an alkaline solution is added to ionize all sampled ambient acid gasses, resulting in an enhanced selectivity. In the selector, the ammonia can diffuse through a second membrane into a purified water stream where an electrolyte conductivity sensor quantifies the resulting ammonium concentration. The realized system is shown to be selective enough not to be influenced by normal ambient carbon dioxide concentrations. Experiments with a gas flow of 3 ml/min, containing ammonia concentrations ranging from 9.8 to 0.3 ppm in a nitrogen carrier flow, into a 15 μl/min sample solution flow and finally into a 5 μl/min purified water stream have been carried out and show that the system is sensitive to ammonia concentration below 1 ppm. 相似文献
65.
Delanoye SN Herrebout WA van der Veken BJ 《The journal of physical chemistry. A》2005,109(43):9836-9843
Complexation enthalpies of the complexes of the haloforms HCCl(n)F(3-)(n) (n = 0-3) with dimethyl ether, oxirane, and acetone have been determined in liquid krypton and/or liquid argon using infrared spectroscopy. The same quantities were derived starting from ab initio complexation energies, calculated at the MP2=FULL/aug-cc-VTZ level, and by correcting these energies for thermodynamic and solvent contributions. The two sets of data are compared and discussed. 相似文献
66.
67.
Haojie Zhang Dr. Dirk J. Hagen Prof. Xiaopeng Li Dr. Andreas Graff Dr. Frank Heyroth Dr. Bodo Fuhrmann Dr. Ilya Kostanovskiy Dr. Stefan L. Schweizer Dr. Francesco Caddeo Prof. A. Wouter Maijenburg Prof. Stuart Parkin Prof. Ralf B. Wehrspohn 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(39):17324-17329
68.
Cats Peter Sitlapersad Ranisha S. den Otter Wouter K. Thornton Anthony R. van Roij René 《Journal of solution chemistry》2022,51(3):296-319
Journal of Solution Chemistry - We present a study of the structure and differential capacitance of electric double layers of aqueous electrolytes. We consider electric double layer capacitors... 相似文献
69.
70.
Kamalika Sen Wouter A. P. Breeman H. Th. Wolterbeek 《Journal of Radioanalytical and Nuclear Chemistry》2012,292(2):683-687
The present article describes the probable speciation of 68Ga radionuclide just before labeling to DOTA peptides for PET imaging. The 68Ga eluted from an anion exchange column after its purification was analyzed for its elemental composition and pH at several
stages. Neutron activation analysis of the eluted fractions yields the concentrations of Na and Cl, pH measurements indicate
the concentration of free H+ ions in the medium and specific activity calculations indicate the concentration of 68Ga in the solution. Using all these information we get the idea of speciation of no carrier added Ga in the eluted fractions
from CHEAQS programme. The estimations indicate that Ga is mostly present as GaCl2+ in the total MiliQ eluate. However, just before labeling of DOTA the pH of the Ga-containing eluate is adjusted to ~3.5 using
HEPES buffer and at that condition Ga remains as Ga3+ species which is responsible for a successful and efficient labeling. The MilliQ eluate collected before actual labeling
was estimated for trace elements using inductively coupled plasma atomic emission spectrometry was found to contain a few
ppb of Al, Co, Pd and Pt that did not interfere in the actual labeling. A clear idea about the prerequisite of 68Ga species before labeling to a peptide might be of special interest for its judicious application as a radiopharmaceutical. 相似文献