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111.
S. Sugunan D. John N. K. Renuka M. Varghese K. Sreekumar C. G. Ramankutty 《Reaction Kinetics and Catalysis Letters》1999,66(1):39-45
The electron donating properties of manganese ferrospinels of various compositions (MnFe2O4, Mn1.2Fe1.8O4, Mn2FeO4 and Mn2.5Fe0.5O4) were studied from the adsorption of electron acceptors of various electron affinity values from acetonitrile as solvent.
The limit of electron transfer from the oxide surface is from 1.77 to 2.40 eV in terms of the electron affinity of the electron
acceptor. The data have been correlated with the catalytic activity of these oxides towards autoxidation of sulfites. Both
weak and strong electron donor sites catalyze the reaction. 相似文献
112.
Cellulose acetate being important in the fiber and textile industries is usually prepared from high quality cellulose such as cotton linters and wood pulps with an alpha cellulose content of more than 95%. In this section, therefore, wood pulps and cotton linters appropriate for cellulose acetate production were discussed in their chemical and physical properties so as to use them judiciously as natural raw materials for cellulose acetate production. 相似文献
113.
114.
Yupeng Liu Dr. Tian-Bing Ren Dr. Dan Cheng Jianing Hou Prof. Dongdong Su Prof. Lin Yuan 《ChemistryOpen》2019,8(10):1251-1257
The novel ratiometric fluorescent probe HPQRB with an ESIPT effect based on Michael addition for highly sensitive and fast detection of sulfite in living HepG2 cells is reported. HPQRB can be easily synthesized by a two-step condensation reaction. HPQRB has a large emission shift (Δλ=116 nm), which is beneficial for fluorescence imaging research, and its sulfite-responsive site is based on a rhodamine-like structure with the emission peak at 566 nm, which decreases with increasing sulfite concentration. and its HPQ structure always has an ESIPT effect throughout the reaction process, keeping the emission peak at 450 nm as a self-reference. In particular, HPQRB has high selectivity for sulfite and responds quickly (within 30 s) with a low detection limit (44 nM). Furthermore, HPQRB has been successfully used for fluorescence imaging of sulfite in HepG2 cells, demonstrating the superior ability to detect sulfite under physiological conditions. 相似文献
115.
建立了离子交换-电导检测离子色谱法测定假冒卷烟所用熏硫烟叶中亚硫酸盐的检测方法。选用Ion-Pac AS11-HC型分离柱,以15 mmol/L KOH为淋洗液,样品经10 mmol/L KOH溶液浸提后,过滤进样分析。SO32-浓度在0.2~20.0 mg/L范围内与色谱峰面积呈良好的线性关系,线性相关系数r=0.999 6。该法测定结果的相对标准偏差为1.96%(n=6),样品加标回收率为92.50%~98.20%,检出限为0.051 mg/L。 相似文献
116.
《Analytical letters》2012,45(1-3):48-57
A rapid chemiluminescence (CL) reaction was observed when Ce(IV) was injected into the mixed solution of pyridoxine hydrochloride and sodium sulfite. A new flow-injection CL method for the determination of pyridoxine hydrochloride was established. The detection limit (3σ) was 0.5 mg/L pyridoxine hydrochloride and the relative standard deviation (RSD) was 3.3% (n = 11, γ = 5 mg/L). The CL intensity responded linearly to the concentration of pyridoxine hydrochloride in the ranges 1.0–10.0 mg/L and 10.0–100.0 mg/L with linear correlation coefficients of 0.9994 and 0.9991, respectively. The method had been applied to the determination of pyridoxine hydrochloride in tablets and injections successfully. 相似文献
117.
118.
基于迈克尔加成反应和分子内电荷转移机理设计合成了一个比率型荧光探针MSP,并将其用于对亚硫酸盐和硫化氢的区分检测。强吸电子基团丙二腈的引入,使得探针的吸收和发射波长红移,同时极大地提高了探针与亚硫酸盐的反应速率,实现了对亚硫酸盐的快速检测。当反应时间延长至3 h时,硫化氢的存在使得探针的荧光波长蓝移至510 nm且强度显著增强,探针在两个波长下的荧光比率(I510/I690)增强约260倍,实现了在不同响应时间和不同光谱通道区分检测亚硫酸盐与硫化氢的目的。该探针具有良好的选择性和竞争性,可分别利用吸收强度比值(A464/A572)和荧光强度比值(I510/I690)定量检测亚硫酸盐和硫化氢,两者检出限分别为0.95μmol/L和0.6μmol/L。该探针还能用于对活细胞内亚硫酸盐和硫化氢的荧光成像。 相似文献
119.
Abstract The oxidation of Cu(II)/tetraglycine complex in borate buffer (pH=9.2) in aqueous medium, by dissolved oxygen is strongly accelerated by S(IV). The reaction is adequate for S(IV) determination as the concentration of (Cu(H-3G4)]? formed is proportional to SO32- concentration. The [Cu(H-3G4)]? presents a maximum absorbance at 365 nm (? = 7400 mol?1.L.cm?1) and it was followed spectrophotometrically by flow injection analysis procedure. The detection limit was 7×10?6 mol.L?1 and the linear regression showed a standard deviation of 0.02% (n=5). Kinetics studies showed the catalytic effect of some transition metal ions, “which can be present in environmental samples, in the oxidation of S(IV). The pseudo-first-order rate constants were determined in the presence of formaldehyde. 相似文献
120.
HUANG Wei-Yuan WU Fan-Hong HUANG Bing-NanShanghai Institute of Organic Chemistry Chinese Academy of Sciences Shanghai China 《中国化学》1994,12(6):549-551
Polyfluoroalkyl iodides, such as Cl(CF2)nI(n=4, 6, 8, 1b-1d) and F(CF2)nI (n=6, 8,1e-1f) reacted with sodium sulfite in neutral aqueous DMF solution to give the corresponding sulfinates Cl(CF2)nSO2Na (n=4, 6, 8, 2b-2d) and F(CF2)nSO2Na (n=6, 8, 2e-2f) in moderate yields. I(CF2)2O(CF2)2SO2F ( la ) reacted under the same condition to give 3-oxa-octafluoropentane-1,5-disulfinates (2a). 相似文献