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991.
苯基荧光酮荧光分光光度法测定痕量锗的研究 总被引:10,自引:0,他引:10
锗具有增血、抗炎症、抗衰老等多种医疗功能 ,因此 ,越来越受到人们的关注。荧光光度法测定微量锗已有报道[1~ 4] 。用苯基荧光酮荧光度法测定锗未见报道。本文利用苯基荧光酮与锗在醋酸 醋酸钠缓冲溶液中络合物形成速度快的优势 ,使其先在缓冲溶液中显色 ,然后在 0 .3mol LHCl介质中测定其荧光强度 ,用于粉煤灰中痕量锗的测定 ,得到满意结果。1 实验部分1 1 仪器与试剂RF - 5 4 0荧光分光光度计 (日本岛津 )。锗标准溶液 ( 1g L) :称取 0 .1 0 0 0g纯锗粉于 5 0ml小烧杯中 ,加入 5mlNaOH ,再加入几滴 30 %H2 O2… 相似文献
992.
993.
Cyril Prknyi Hui Liang Yuan Bo H. E. Strmberg Ariella Evenzahav 《Journal of heterocyclic chemistry》1992,29(4):749-753
The synthesis of ten new substituted 1,3,4-thiadiazolyl-4(3H)-quinazolinones 8–11, 13, 17 , and 20–23 is reported. Compounds 8–11 were prepared by condensation of 5-fluoro-2-methyl-3,1-benzoxazin-4-one (3) and 5-substituted 2-amino-1,3,4-thiadiazoles 4–7. Compound 13 was obtained by condensation of 5-fluoro-2-methyl-3,1-benzoxazin-4-one (3) with DL-α-amino-?-caprolactam (12) . Compound 17 was synthesized by condensation of 6-bromo-2-methyl-3,1-benzoxazin-4-one (16) and 2-amino-5-t-butyl-1,3,4-thiadiazole (5) . Compounds 20–23 were obtained by condensation of 5-chloro-6,8-dibromo-2-methyl-3,1-benzoxazin-4-one (19) and 5-substituted 2-amino-1,3,4-thiadiazoles 4–7, respectively. The substituted 3,1-benzoxazin-4-ones 3, 16, and 19 were obtained in good yield by refluxing the appropriate anthranilic acid, 1,15 , and 18 with acetic anhydride (2) . 相似文献
994.
Synthesis and antimicrobial activity of a perfluoroalkyl-containing quaternary ammonium salt 总被引:1,自引:0,他引:1
A novel perfluoroalkyl-containing quaternary ammonium salt 5 was designed and synthesized. Consequently, the antimicrobial activities of compound 5 were measured with Escherichia coli 8099 as a Gram-negative strain and Staphylococcus aureus ATCC 6538 as a Gram-positive strain. Both the minimum inhibitory concentration (MIC, the lowest concentration of compound 5 that inhibits microbial growth) values of quaternary ammonium salt 5 against Escherichia coli 8099 and Staphylococcus aureus ATCC 6538 were 7.8 μg/ml. 相似文献
995.
996.
[60]Fullerene-fused pyrazolines 1 were prepared by the reaction of C60 with alky diazoacetates under the solid-state high-speed vibration milling conditions as well as in toluene solution. Pyrazolines 1 were stable in refluxing toluene and its thermolysis process in 1,2-dichlorobenzene was investigated, the decomposition rates and activation energies of pyrazolines 1 were obtained. The current work demonstrated that the liquid-phase reaction of C60 with alkyl diazoacetates undergoes via 1,3-dipolar cycloaddition pathway at room temperature, or proceeds via carbene mechanism at a temperature of refluxing toluene, thus clarifies the previous ambiguity of its reaction mechanism. 相似文献
997.
Pei Yuan Wu 《Integral Equations and Operator Theory》1984,7(6):899-904
If T is a contraction on the Hilbert space H and there is an invariant subspace K for T such that T/K is similar to a backward shift, then T is reflexive. If similarity is replaced by quasi-similarity, then the same conclusion holds under the additional condition that the defect index of T be finite.This research was partially supported by National Science Council (Republic of China). 相似文献
998.
A new polymeric chromogenic reagent PA.FPNS has been synthesized by condensing polyallylamine (PA) with 3-(4-formylphenylazo)-4,5-dihydroxynaphthalene-2,7-disulfonic acid (FPNS) and its properties studied. In alkaline media, PA.FPNS reacts with magnesium to form a water-soluble blue complex, whose absorption maximum is at 604 nm. The molar absorptivity (varepsilon) of the complex is 5.2 x 10(4)l mol(-1) cm(-1), which is four times that of the FPNS-Mg complex, and Beer's law is obeyed over the range 0-0.35 mug ml(-1) magnesium. Compared to the corresponding low-molecular-weight FPNS and other chromogenic reagents, PA.FPNS offers considerably improved sensitivity and selectivity for magnesium, which may be attributed to incorporating FPNS into a water-soluble polymer and the effect of the polymeric chain on the reaction microenvironment. Also, a simple and sensitive spectrophotometric method for the determination of magnesium has been developed and applied to water and human fluid samples with satisfactory results. 相似文献
999.
聚苯乙烯型阴离子交换剂的合成方法 总被引:5,自引:0,他引:5
对聚苯乙烯型阴离子交换剂的各种合成方法作了较为全面的评述。指出使用氯甲醚为原料的氯甲基化法由于毒性问题已经受到限制,分析了其它方法在实现工业化生产并最终取代氯甲基化法方面的可能性。 相似文献
1000.
Wolfgang Hnle Walter Schmettow Karl Peters Jen‐Hui Chang Hans Georg von Schnering 《无机化学与普通化学杂志》2004,630(12):1858-1862
The novel ternary polyphosphides M4P21I (M = K, Rb) have been synthesized from the elements in single crystalline form, representing further examples for the formation of mixed crystals between simple salts and binary phosphides. They form as ruby‐red platelets and dark‐red prisms, respectively, and are only slightly sensitive to moisture and oxygen. The compounds are isotypic (Ccmm (no 63); Z = 4; oP104; K4P21I: a = 12.853Å; b = 21.795Å; c = 9.748Å; 1168 hkl, R = 0.033; Rb4P21I: a = 13.281Å; b = 21.868Å; c = 9.771Å; 777 hkl, R = 0.053) and feature corrugated 2D networks formed from two different types of polymerized P7 units. The networks form large cavities filled by M+ and I‐ ions. Zigzag chains of condensed trigonal M6 prisms, centered by the I‐ anions, separate the polyphosphide nets. The mean homoatomic P‐P bond length (d = 2.216Å) corresponds to a P‐P single bond. However, the individual P‐P distances vary with position and function (2.126 ‐ 2.247Å) and these are compared with those of the isolated P21‐3 anion. 相似文献