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311.
Based on the quenching of the fluorescence of CdSe quantum dots (QDs) by spironolactone, a simple, rapid and specific method for spironolactone determination was proposed. In the optimum conditions, spironolactone concentration versus quantum dot fluorescence gave a linear response with an excellent 0.997 correlation coefficient, between 2.5 and 700 mg/mL (6.0-1680 μmol/L) and the limit of detection (S/N = 3) was 0.2 μg/mL (0.48 μmol/L). The contents of spironolactone in pharmaceutical tablets were determined by the proposed method and the results agreed with the claimed values. The possible mechanism for the reaction was also discussed. 相似文献
312.
313.
Hirata K Suzuki T Noya A Takei I Hidai M 《Chemical communications (Cambridge, England)》2005,(29):3718-3720
The reactions of [Cp*MCl2]2(Cp*=eta5-C5Me5, M = Rh, Ir) with thiacalix[4]arene (TC4A(OH)4) and tetramercaptothiacalix[4]arene (TC4A(SH)4) gave the mononuclear complexes [(Cp*M){eta3-TC4A(OH)2(O)2}] and the dinuclear complexes [(Cp*M)2{eta3eta3-TC4A(S)4}] respectively, while the analogous reactions with dimercaptothiacalix[4]arene (TC4A(OH)2(SH)2) produced the tetranuclear complexes [(Cp*M)2(Cp*MCl2)2-{eta3eta3eta1eta1-TC4A(O)2(S)2}]. 相似文献
314.
He X Pu W Han J Chen J Lu J Jiang C Wan C 《The journal of physical chemistry. B》2005,109(49):23141-23144
A method is proposed based on mode coupling theory in which the ion transference number is introduced into the theory. The ionic limiting molar conductivities of LiPF6, LiClO4, LiBF4, LiCF3SO3, Li(CF3SO3)2N, LiC4F9SO3, and LiAsF6 in PC(propylene carbonate), GBL(gamma-butyrolactone), PC(propylene carbonate)/EMC(ethylmethyl carbonate), and PC(propylene carbonate)/DME(dimethoxyethane) are calculated based on this method, which does not involve any adjustable parameter. The results fit well to the literature data which are calculated by an empirically adjusted formula. This presents a potential way to calculate the conductivities of Li-ion battery electrolytes. 相似文献
315.
Thermogravimetry study of the pyrolytic characteristics and kinetics of macro-algae Macrocystis pyrifera residue 总被引:1,自引:0,他引:1
Hui Zhao Huaxiao Yan Shuangshuang Dong Yan Zhang Binbin Sun Congwang Zhang Yanxiang Ai Biaoqi Chen Qi Liu Tongtong Sui Song Qin 《Journal of Thermal Analysis and Calorimetry》2013,111(3):1685-1690
Macrocystis pyrifera is one important marine macro-algae, while its residues produced by industrial alginate extraction is a hot potato. To figure out whether its residue is suitable for pyrolysis for biofuel, the pyrolytic characteristics and kinetics of macro-algae M. pyrifera residue was investigated using thermogravimetric method from 50 to 800 °C in an inert argon atmosphere at different heating rates of 5, 10, 20, and 30 °C min?1. The activation energy and pre-exponential factor was calculated by Flynn–Wall–Ozawa, Kissinger–Akahira–Sunose, and Popescu methods, and the kinetic mechanism was deduced by Popescu method. The results showed that the primary devolatilization stage of M. pyrifera residue can be described by Jander function $ \left(\left[ {1 - \left( {1 - \alpha } \right)^{1/3} } \right]^{2}\right) $ . The average activation energy of M. pyrifera residue was 222.4 kJ mol?1. The results suggested that the experimental results and kinetic parameters provided useful information for the design of pyrolytic processing system using M. pyrifera residue as feedstock. 相似文献
316.
化合物库的组合技巧和组合合成 总被引:2,自引:0,他引:2
从化合物库的组合技巧和组合合成方法两个方面探讨了组合化学及其在药物开发中的应用。 相似文献
317.
The electrocatalysis oxidation of guanosine‐5′‐monophosphate (GMP) was investigated on Mg‐Al layered double hydroxide (LDH) functionalized with sodium dodecyl sulfate (SDS) and room temperature ionic liquid (RTIL) modified glass carbon electrode (GCE). The cyclic voltammogram of GMP on the modified electrode (RTIL/ LDH‐SDS/GCE) exhibited a well defined anodic peak at 1.091 V in 0.2 mol·L?1 pH 4.4 acetate buffer solution. The GMP oxidation was enhanced in the presence of anionic surfactant in the ?lms. The results suggest that the surfactant molecules intercalate the LDH layers to preconcentrate GMP molecules and the RTIL showed good ionic conductivity. The experimental parameters were optimized, the kinetic parameters were investigated and the probable oxidation mechanism was proposed. Under the optimized conditions, the oxidation peak current was proportional to GMP concentration in the range from 5.0×10?7 to 1.0×10?4 mol·L?1 with the correlation coefficient of 0.9987 and the detection limit was 1.0×10?7 mol·L?1. The RTIL/LDH‐SDS/GCE showed a good electrochemical response to the oxidation of GMP and would be developed into a new biosensor. 相似文献
318.
Yong Shen Ai‐Xue Zuo Zhi‐Yong Jiang Xue‐Mei Zhang Hong‐Ling Wang Ji‐Jun Chen 《Helvetica chimica acta》2011,94(1):122-126
Two new C20‐diterpenoid alkaloids, named aconicarchamines A and B ( 1 and 2 , resp.), were isolated from Aconitum carmichaelii. By UV, IR, MS, and 1D‐ and 2D‐NMR analyses, their structures were elucidated as 14,17‐dihydro‐14,17‐dihydroxyajabicine and 15‐O‐acetyllassiocarpine. Compound 1 is the third C20‐diterpenoid alkaloid with the lycoctine skeleton bearing an exocyclic C‐atom at C(14). 相似文献
319.
A differential pulse voltammetric method was developed for the simultaneous determination of paracetamol, 4-aminophenol and dopamine at pH 7.0 using a glassy carbon electrode (GCE) coated with gold nanoparticles (AuNPs) and a layered double hydroxide sodium modified with dodecyl sulfate (SDS-LDH). The modified electrode displays excellent redox activity towards paracetamol, and the redox current is increased (and the corresponding over-potential decreased) compared to those of the bare GCE, the AuNPs-modified GCE, and the SDS-LDH-modified GCE. The modified electrode enables the determination of paracetamol in the concentration range from 0.5 to 400???M, with a detection limit of 0.13???M (at an S/N of 3). The sensor was successfully applied to the stimultaneous determination of paracetamol and dopamine, and of paracetamol and 4-aminophenol, respectively, in pharmaceutical tablets and in spiked human serum samples. Figure
1. Gold nanoparticles and organophillic layered double hydroxide modified glassy carbon electrode was fabricated. 2. The modified electrode displayed excellent redox activity towards paracetamol. 3. This electrode was successfully applied to the simultaneous determination of paracetamol and dopamine, and of paracetamol and 4-aminophenol, respectively 相似文献
320.
Ogawa A Miyamae Y Honma A Koyama T Yazawa K Shigemori H 《Chemical & pharmaceutical bulletin》2011,59(5):672-675
A new compound, pycnalin (1), together with four known compounds, ginnalins A (2), B (3), C (4), and 3,6-di-O-galloyl-1,5-anhydro-D-glucitol (3,6-di-GAG) (5), were isolated from Acer pycnanthum. The structure of 1 was determined on the basis of 2D-NMR spectral data and synthesis of 1. Pycnalin (1) is the first 1,5-anhydro-D-mannitol linked to a gallic acid, while compounds 2-5 were 1,5-anhydro-D-glucitol linked to gallic acids. All compounds were tested in vitro for α-glucosidase inhibitory and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities. Pycnalin (1) exhibited moderate α-glucosidase inhibitory activity as well as free radical scavenging activity. Ginnalin A (2) and 3,6-di-GAG (5), which have two galloyl groups, exhibited potent α-glucosidase inhibition, compared to those of other compounds 1, 3, and 4 containing a galloyl group. These results suggest that α-glucosidase inhibition is influenced by the number of galloyl groups. 相似文献