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71.
A new application of continuous wavelet transform (CWT) to overlapping peaks in a chromatogram was developed for the quantitative analysis of amiloride hydrochloride (AML) and hydrochlorothiazide (HCT) in tablets. Chromatographic analysis was done by using an ACQUITY ultra-performance LC (UPLC) BEH C18 column (50 x 2.1 mm id, 1.7 pm particle size) and a mobile phase consisting of methanol-0.1 M acetic acid (21 + 79, v/v) at a constant flow rate of 0.3 mL/min with diode array detection at 274 nm. The overlapping chromatographic peaks of the calibration set consisting of AML and HCT mixtures were recorded rapidly by using an ACQUITY UPLC H-Class system. The overlapping UPLC data vectors of AML and HCT drugs and their samples were processed by CWT signal processing methods. The calibration graphs for AML and HCT were computed from the relationship between concentration and areas of chromatographic CWT peaks. The applicability and validity of the improved UPLC-CWT approaches were confirmed by recovery studies and the standard addition technique. The proposed UPLC-CWT methods were applied to the determination of AML and HCT in tablets. The experimental results indicated that the suggested UPLC-CWT signal processing provides accurate and precise results for industrial QC and quantitative evaluation of AML-HCT tablets. 相似文献
72.
Eda Cesaratto Joachim von zur Gathen Guillermo Matera 《Journal of Number Theory》2013,133(4):1409-1434
“Most” hypersurfaces in projective space are irreducible, and rather precise estimates are known for the probability that a random hypersurface over a finite field is reducible. This paper considers the parametrization of space curves by the appropriate Chow variety, and provides bounds on the probability that a random curve over a finite field is reducible. 相似文献
73.
Melis Kesik Ozgecan Kocer Fulya Ekiz Kanik Naime Akbasoglu Unlu Eda Rende Evren Aslan‐Gurel Rene M. Rossi Yasemin Arslan Udum Levent Toppare 《Electroanalysis》2013,25(8):1995-2006
Surface functionalization plays a crucial role in the design of biosensors. For this purpose, a novel functional monomer, 6‐(4,7‐bis(2,3‐dihydrothieno[3,4‐b][1,4]dioxin‐5‐yl)‐2H‐benzo[d][1,2,3]triazol‐2‐yl)hexan‐1‐amine (BEDOA‐6), was designed and synthesized. Poly(BEDOA‐6) was utilized as an immobilization matrix for glucose oxidase biosensor construction. Moreover, polymethylmethacrylate (PMMA) layered silicate nanocomposites were prepared by in situ suspension polymerization. Conducting polymer surface was modified with PMMA/clay nanocomposite material and a glucose biosensor was developed. In addition, XPS and SEM were utilized to characterize the surface properties. The biosensor shows a wide linear range between 2.8 µM and 1.2 mM to glucose with a low detection limit of 1.99 µM. Finally, the biosensor was tested on serum samples containing actual human blood. The results were in well‐agreement with a reference method. 相似文献
74.
Yusaku Eda Kennosuke Itoh Yoshio N. Ito Mamoru Fujitsuka Tetsuro Majima 《Supramolecular chemistry》2013,25(9):517-523
2,6-Bis(porphyrin)-substituted 3,5-dimethylpyrazine and its zinc complex bound C70 to yield 1:1 inclusion complexes, which were characterised by ESI-MS, UV–vis, fluorescence and NMR spectroscopies. Association constants of the C70 complexes were determined by fluorescence and NMR spectral analyses. A decrease in absorbance of the Soret band of the pyrazine derivative by the effect of C70 was observed, suggesting the existence of a charge transfer interaction between C70 and porphyrin. Experimentally reliable values for the association constants were obtained by the NMR method and were about six times larger than those of the corresponding C60 complexes. Palladium complexation of the porphyrin–pyrazine ligand was found to enhance the association with fullerene. The association constant of 2,6-bis(porphyrin-Zn)-substituted 3,5-dimethylpyrazine-Pd(II) complex with C70 was determined to be 8400 ± 900 M? 1. From the comparison of the association constants, it was found that inclusion room for C70 in the Pd(II) complex was maintained, juxtaposed between porphyrins attached to the opposite sides of the pyrazine ligands. 相似文献
75.
A fluorescent probe based on silicon quantum dots (SiQDs) was developed for the selective and sensitive detection of oxytetracycline (OTC) via the inner filter effect (IFE). The water-soluble fluorescent SiQD was synthesized based on the reaction of 3-Aminopropyltriethoxysilane (APTES) and sodium citrate as precursors by the one-pot hydrothermal process. The strong fluorescence emission of quantum dots (QDs) was obtained at 440 nm when excited at 350 nm and OTC had a broad absorption band between 200 and 400 nm. The excitation spectrum of SiQDs was completely overlapped with the absorption spectrum of OTC. The light at an excitation wavelength of QDs absorbed by OTC caused a decrease in fluorescence intensity with an increase in the concentration of OTC. Under optimal conditions, the linear concentration range was 0.92–9.2 µg mL1 with a detection limit (LOD; S/N = 3) of 0.19 µg mL -1 . The proposed method was applied to the determination of OTC in milk samples and satisfactory recoveries (98.8–100.5%) with low RSD % values (0.93–2.31%) were achieved. This simple, selective, sensitive, rapid, and cheap method can be used as a promising tool for OTC analysis in food safety. 相似文献
76.
77.
In our earlier papers we constructed examples of 2-dimensional nonaspherical simply-connected cell-like Peano continua, called
Snake space. In the sequel we introduced the functor SC(−,−) defined on the category of all spaces with base points and continuous mappings. For the circle S
1, the space SC(S1, *){SC(S^1, {_{*}})} is a Snake space. In the present paper we study the higher-dimensional homology and homotopy properties of the spaces SC(Z, *){SC(Z, {_{*}})} for any path-connected compact spaces Z. 相似文献
78.
Evidence for an electron trapping centre produced by ionizing radiations in a single crystal of maleic acid has been obtained by electron spin resonance. When the crystal is irradiated at 77 K several paramagnetic species are produced. One of them is the species in which the unpaired electron occupies the delocalized π orbital and interacts with the two vinylene protons. The hyperfine tensors of the two vinylene protons, which are typical of α proton coupling, are (-13·0, -8·5, -3·2) and (-6·4, -5·2, -1·9)G, respectively. The g tensor is (2·0043, 2·0040, 2·0024). The principal directions of the hyperfine and g tensors give information about the electron trapping centre in which the framework of the molecule is preserved. The probable structure of this centre is the delocalized carboxyl anion although the possibility of its protonated form cannot be completely excluded. 相似文献
79.
80.