7—[（4—甲基2—胂酸基苯）偶氮]—8—羟基喹啉—5—磺酸荧光光度法测定氟

本文介绍了７－［（４－甲基－２－胂酸基苯）偶氮］－８－羟基喹啉－５－磺酸的合成方法以及性能，详细研究了氟对该试剂与铝形成的荧光的熄灭作用，建立了荧光法测定微量氟的新方法。应用于水样和牙膏中的氟的测定，效果良好。     

荧光猝灭法测定微量氟的研究

建立了氟的铝－钙指示剂络合物荧光猝灭测定法。本法λｅｘ＝５７０ｎｍ，λｅｍ＝６００ｎｍ，线性范围为５～１６０ｎｇ／ｍＬＦ＾－。对５ｎｇ／ｍｌＦ＾－重复１１次测定结果的相对标准偏差为２．４％，可直接用于温泉水中氟的测定。     

高氟铝和铝引起低龄鸡骨发育不全

进行了高氟铝和铝对低龄鸡骨损害的实验。５７日龄鸡９６只随机分为８组,毒物加进饲料,实验期３个月。结果表明,各高氟、高氟铝组骨氟均数倍于对照组,低铝组骨氟显著升高;单饲ＮａＦ组骨铝增高近３倍,高氟铝组骨氟比ＮａＦ组和病区玉米组低１／３以上,骨铝低约５０％;单饲铝达对照４～２１倍的骨铝与对照组接近。饲氟与骨氟ｒ＝０．７７,与骨铝ｒ＝０．６５;饲铝与骨铝ｒ＝－０．４６,与骨氟ｒ＝－０．５３;骨氟与骨铝ｒ     

氟钽酸钾中微量碳的测定

为了完全消除氟钽酸钾试样中的氟对燃烧法测定其中微量碳的影响,提出用铝片包裹试样,在８８０℃通氧燃烧时,试样中的氟与铝形成不易挥发的氟化铝,从而使大部分氟保留在瓷料中。尚有残留的少量氟逸出,可使经过装有２－「５－（８－羟基喹啉）偶氮』－４－,５－二苯基咪唑和二氧化锰的分离柱而完全除去。试样中微量碳最终用库仑不测定。     

用氟离子选择性电极测定岩石中的三氧化二铝

用氟电极作指示电极以电位滴定法测定铝的方法已有许多报导。我们在前一工作的启示下,又提出用氟电极的直接电位法来测定岩石中的三氧化二铝。方法基于在微酸性溶液中,铝与氟化钾作用定量生成铝氟酸钾沉淀: AlCl_3+6KF→K_3AlF_(?)↓+3KCl用氟电极测定过量沉淀剂中的氟,间接计算出三氧化二铝的含量。方法用于测定粘土、花岗岩、长石、闪长石中的三氧化二铝,获得了满意的结果。特别适用于高含量铝的测定,干扰少,无需分离,方法简便快速。     

控制电位氟-金属离子配位滴定法同时测定铝和镓

1引言铝和镓作为同族元素,有很多相似的性质。对它们的同时测定,无论在理论上或在实际应用中,均有一定的意义。本实验以氟离子溶液作滴定剂,氟离子选择性电极作指示电极,利用氟铝及氟镓之间的配位反应及控制电位滴定法,对铝和镓的同时测定进行了研究。用氟离子溶液滴定铝离子和     

铝氟联合中毒暨铝引起少儿钙磷铁锌生物有效利用不良综合征

对某村普查筛出的铝氟联合中毒病人及高氟,高氟铝、高铝的实验种鸡进行动态研究。结果表明,氟含量〉４０＊１０＾－６的主食玉米促成了一般摄铝浓度人群的铝吸收和蓄积,饲铝超过一般浓度１－４倍的童鸡便有肝、肾铝蓄积、骨铝反而显著下降,但均出现低龄人群和实验动物的高钙血和高骨矿性骨营养不良软化,高全血磷的ＡＴＰ生成减少,全血铁增高的缺铁性小细胞性贫血,低锌症,智能和体能下等钙磷铁锌生物有 良和低素质综合症,随     

受腐蚀的不锈钢片和铝片中微量氟的分离和测定

大量铁或铝存在时欲分离微量氟颇为困难,即使采用氟离子选择电极测定微量氟亦需避免其影响。至于用茜素络合剂比色测定氟,自1959年Belcher提出后已得到广泛的应用。虽然,Feigl早就建议借提高溶液的pH值可使铁(Ⅲ)和铝(Ⅲ)的氟络合离子解蔽。向井等曾用8-羟基喹啉沉淀分离和测定共存的铝和氟。但两者均无分离微量氟的结果。而且,单凭提高pH并不能使氟离子与铝(Ⅲ)完全分离。本文用沉淀法使微量氟离子解蔽而分别与大量铁(Ⅲ)和铝(Ⅲ)分离,继借二苯胍阳离子对茜素络合剂-铈(Ⅲ)-氟离子三元络合物中亲水基团的封闭作用,以有机溶剂萃取分光光度测定微量氟。此法     

乙醇-水介质中氟-铝沉淀电位滴定体系研究

由于氟-铝的多级络合反应,在水溶液中用氟化物直接滴定铝没有明显的电位突跃,若用乙醇-水介质,则电位突跃明显^[1～3].本文对乙醇-水介质中氟-铝沉淀电位滴定体系的化学平衡进行了研究.测定了在不同浓度的乙醇介质中氟-铝的络合比及各级络合物的稳定常数等参数.实验表明用F^-电位滴定测定铝可取得较好结果.     

萃取光度法测定痕量氟的改进

本文提出一种新的测定痕量氟的萃取光度法，采用Ｎ，Ｎ－二甲苯胺作萃取剂，证实异戊醇进入萃取的多元络合物组成，以六偏酸钠和乙酰丙酮可消除多量铁、铝的干扰，生物样品则宜用过氧化氢及过氧化钠高压分解。本法可检测多种水样中１０＾－９级的氟，相对标准偏差〈２％。     

THE EFFECT OF FLUORIDE ON BINDING and PHOTODYNAMIC ACTION OF PHTHALOCYANINES WITH PROTEINS

Fluoride inhibits chloroaluminum phthalocyanine tetrasulfonate (AlPcS)-induced photohemolysis when added to dye loaded cells prior to light exposure. The mechanism by which F- exerts this effect was studied by measuring the binding of phthalocyanine (Pc) to various proteins in the absence and presence of F-. Parallel measurements were made of the photodynamic action under these conditions. Fluoride reduced the binding to proteins of AlPcS and CoPcS. The binding of CuPcS, ZnPcS and H2PcS was not affected. When bound to bovine serum albumin and exposed to light, H2Pc, ZnPc and AlPcCl were bleached at a biphasic rate. Only the photobleaching of AlPcCl was affected by F-. The effect of F- was to inhibit the initial rapid phase without affecting the slower phase. In the presence of D2O only the second phase of photobleaching was enhanced, in the absence or presence of F-. No effect of F- was observed on tryptophan photooxidation or glyceraldehyde-3-phosphate dehydrogenase photoinactivation by AlPcS. Crosslinking of spectrin monomers photosensitized by AlPcS was inhibited by F- in parallel with the reduced binding of dye to the protein. It is concluded that F- exerts its effect by complexing with metal ligands of Pc. As a result, the dye may be released from the protein or the binding mode may be changed in such a way that effective photochemistry is prevented. Primary photophysical processes of Pc most probably are not affected by F-.     

荧光熄灭法测定微量氟的研究和应用

在环境监测中微量F~-的分析受到很大的重视.过去采用了分光光度法、离子选择电极法和荧光光度法,前两种方法选择性好,但灵敏度略低;荧光光度法灵敏度较高,可直接测定简单样品中的微量氟.在测定氟的荧光方法中,均是采用荧光熄灭法.此法的特点是灵敏度高,但操作繁琐,很少用于实际样品分析.我们研究了氟的几个新体系,从中筛选出灵敏度高、操作简便的锆-8-羟基喹啉-5-磺酸体系.在水溶液中测定,1μg F~-使体系荧光强度下降68％,与文献报道的体系相比是较高的.本法灵敏度为0.002μgF~-/mL,是测定氟的最灵敏方法之一.     

Determination of the content of sulfonyl fluoride groups in the copolymer of tetrafluoroethylene with perfluoro(3,6-dioxa-4-methyl-7-octene)sulfonyl fluoride

The applicability of Fourier IR spectroscopy to determination of the content of sulfonyl fluoride groups in the copolymer of tetrafluoroethylene with perfluoro(3,6-dioxa-4-methyl-7-octene)sulfonyl fluoride (F-4SF copolymer) was examined. A procedure was suggested for determination of sulfonyl fluoride groups, based on a correlation between the analytical signals in the IR absorption spectrum of F-4SF and the sulfur content in F-4SF samples.     

Tribological properties of fluoroplastics modified with fullerene black in sliding friction with water lubrication

Effect of fullerene black additives on the antifriction properties and wear resistance of F-4 and F-4K20 fluoroplastics in sliding friction against steel with water lubrication was examined.     

RELATIVE REACTIVITIES OF THE EXCITED STATES OF FUROCOUMARINS FOR [2+2] PHOTOCYCLOADDITION REACTION WITH TETRAMETHYLETHYLENE

Abstract— The Stern-Volmer constants for fluorescence quenching by tetramethylethylene decrease in the order DMC ≫ DHP > F-2 > 8-MOP. The same order was observed for the quantum yields of [2+2] cycloaddition reaction with tetramethylethylene on direct irradiation. In [2+2] photocycloaddition of F-2 with tetramethylethylene in ethanol, the ratio of quantum yields deduced from singlet and triplet states of F-2; φ₃⁰/φ₁⁰, is about 5. The excited triplet state is the reactive state for the [2+2] photocycloaddition of F-2 with tetramethylethylene in solution but the excited singlet state of F-2 becomes very important in biological conditions.     

Computational study of location and role of fluoride in zeolite structures

The distribution of fluoride ions has been studied in the pure silica IFR, ITH, IWR, STF and STT zeolite structures using computational techniques. The interactions between the F- and SDA+ ions (where SDA is the organic structure directing agent) are able to explain the F- cage occupation found experimentally. While studying the short-range fluoride-framework interactions, a relationship was found between the Si atoms forming the pentacoordinated units and the lowest F- defect energies, which rationalizes the experimental Si-F bonding in terms of energetic stability. It is proposed that the F- location is governed by a two step process. In a first stage, the electrostatic long-range forces and, especially, the interactions between the F- and the SDA+ ions, decide which cage will be filled with F-; in a second stage, once the F- cage location is decided, the F- forms a covalent bond with a Si site to form an energetically stable pentacoordinated unit [SiO4/2F]-.     

Novel supramolecular gelation route to in situ entrapment and sustained delivery of plasmid DNA

In this work, cationic block copolymer (F-68-PLL) composed of Pluronic F-68 and poly(L-lysine) segments was first prepared for the binding with plasmid DNA due to the electrostatic interaction between poly(L-lysine) segments and plasmid DNA, and subsequently used to interact with α-cyclodextrin (α-CD) in aqueous system for the supramolecular gelation by the inclusion complexation between Pluronic F-68 segments and α-CD. It was found that such a fabrication process could lead to the in situ entrapment of plasmid DNA into the supramolecular hydrogel matrix under mild conditions. Depending on the amounts of F-68-PLL and α-CD, the resultant hybrid hydrogel was found to have adjustable gelation time and mechanical strength. For the plasmid DNA complexes released from the supramolecular hydrogel, controlled release and sustained gene transfection were confirmed.     

用基于苯并噻二唑衍生物的比率荧光化学传感器检测氟离子

研制了一种用于灵敏、快速地检测溶液中的氟离子的基于苯并噻二唑衍生物的荧光传感器.4,7-二溴-2,1,3-苯并噻二唑与三甲基硅基乙炔通过Sonogashira偶联反应得到二取代的三甲基硅基乙炔苯并噻二唑;将该化合物用于检测氟离子,分析了检测灵敏度和选择性.结果表明,在乙腈和水(V/V=9∶1)混合溶液中,合成的苯并噻二唑衍生物的最大发射波长峰值为455nm(激发波长为376nm);就所测试的F-,Cl-,Br-,I-,ClO4-,AcO-,NO3-,H2PO3-,CN-和HSO4-等阴离子而言,仅F-可以脱除三甲基硅保护基使得该化合物荧光最大发射波长蓝移至435nm,荧光强度降低60%,且最低检测限可达4.5×10-8 mol/L.因此,二取代的三甲基硅基乙炔苯并噻二唑应用于氟离子检测具有很好的灵敏度和选择性.     

Luminescent characteristics of liquid-phase systems and polymer compositions containing europium β-diketonates solubilized with pluronics

The solubilization of europium β-diketonate complexes with amphiphilic polymers, ternary block copolymers of ethylene and propylene oxides (Pluronics), was shown to change luminescence intensity in such complexes. The association of europium β-diketonate complexes with Pluronics was proved by atomic force microscopy of agglomerates crystallized on mica surfaces from chloroform solutions of Pluronic F-127 in the presence and absence of the luminophores under study. In the absence of luminophores, Pluronic F-127 crystallized on a mica surface had a dendrite-like structure, while the evaporation of chloroform solutions containing both europium β-diketonates and Pluronic F-127 gave crystallized luminophore-Pluronic associates as compact islands with a characteristic size of ～0.5 μm.