催化动力学光度法测定痕量铁(Ⅲ)--茜素绿-H2O2指示反应体系

本法基于铁(Ⅲ)对过氧化氢氧化茜素绿反应的催化作用,提出一种高灵敏地测定痕量铁(Ⅲ)的新方法.该方法线性范围为2～36μg·L-1、40～1800μg·L-1检测限为6.04×10-7g·L-1.测定出反应表观活化能Ea=45.26kJ/mol.此法用于河水,自来水等样品中铁的测定,结果满意.     

催化动力学光度法测定微量铁的研究—Fe（Ⅲ）—结晶紫—H2O2体系

研究了在H2 SO4 介质中 ,Fe(Ⅲ )对H2 O2 氧化结晶紫褪色反应的催化作用及最佳实验条件和动力学参数 ,建立了测定痕量铁的新方法 .方法的检出限为 2 73× 10 -11g/L ,测定范围 0～ 2 5 μg/L ,用于各种水中微量铁的测定 ,获得满意结果     

Fe（Ⅲ）—H2O2—酸性铬蓝K体系催化光度法测定痕量铁

在pH=9.35的硼砂-HCl体系缓冲溶液中,Fe(Ⅲ)能催化酸性铬蓝K的氧化褪色反应,据此建立了一个测定痕量铁的新催化动力学分光光度法.该方法在所选条件下,lg(A     

2-(5-羧基-1,3,4-三氮唑偶氮)-5-二乙氨基苯胺-过氧化氢催化动力学光度法测定痕量铁的研究

在pH3.5的HAc-NaAc缓冲溶液介质和加热条件下,痕量铁(Ⅲ)对H2O2氧化2-(5-羧基-1,3,4-三氮唑偶氮)-5-二乙氨基苯胺(CTZAN)的褪色反应具有显著的催化作用,褪色反应程度与铁(Ⅲ)量在一定范围内呈线性关系,建立了测量痕量铁(Ⅲ)的催化动力学光度法。褪色体系的最大吸收波长为425nm,Fe(Ⅲ)质量浓度在(0.01—0.20)mg/L范围内符合线性关系,回归方程为ΔA=4.491ρ+0.0066(ρ:mg/L),相关系数为0.9982,检出限为2.02×10-9g/mL。方法用于面粉及头发中痕量铁的测定,结果与AAS测定结果相符。     

不同树脂负载铁(Ⅲ)活化H_2O_2降解有毒有机污染物

将不同类型树脂(大孔强碱性阴离子交换树脂D201、螯合树脂D401、大孔强酸性苯乙烯阳离子交换树脂D001)负载铁(Ⅲ)作为光催化剂,在可见光(≥420nm)照射下,通过外加H2O2光催化降解罗丹明B(Rhodamine B,RhB).结果表明,在可见光和pH=6.2条件下,螯合树脂D401负载铁(Ⅲ)光催化剂具有最好的光催化活性.该催化剂对RhB降解的最佳条件为:催化剂用量400mg/L,H2O2浓度7.49×10-4 mol/L.并且,该催化剂在可见光条件下对无色小分子二氯苯酚(2,4-Dichlorophenol,DCP)也具有良好的光催化降解活性,表明其具有可见光催化活性.同时,跟踪测定了螯合树脂D401负载铁(Ⅲ)光催化剂在RhB降解过程中羟基自由基(·OH)的变化,结果表明光催化机理涉及·OH氧化历程.     

催化动力学光度法测定痕量铁(Ⅲ)——茜素绿-H_2O_2指示反应体系

本法基于铁(Ⅲ)对过氧化氢氧化茜素绿反应的催化作用,提出一种高灵敏地测定痕量铁(Ⅲ)的新方法。该方法线性范围为2～36μg·L-1、40～1800μg·L-1检测限为6.04×10-7g·L～1。测定出反应表观活化能Ea=45.26kJ/mol。此法用于河水,自来水等样品中铁的测定,结果满意。     

催化动力学光度法测定痕量铁-Fe(Ⅲ)-KBrO_3-酸性铬蓝K体系

本文研究了在稀硫酸介质中,痕量铁(Ⅲ)催化溴酸钾氧化酸性铬蓝K褪色的新指示反应及动力学条件,建立了催化动力学光度法测定痕量铁的新方法。方法的灵敏度为9.6×1O~(-10)gEe(Ⅲ)/ml。线性范围为0.05—3.5μgFe(Ⅲ)/25ml。方法用于环境水样和人发中痕量铁的测定,结果满意。     

显色剂2-(5-羧基-1,3,4-三氮唑偶氮)-5-二乙氨基苯胺与铁的显色反应

研究了显色剂2-(5-羧基-1,3,4-三氮唑偶氮)-5-二乙氨基苯胺(简称CTZAN)与铁的显色反应.结果表明,在pH 6.0的HAc-NaAc缓冲体系中,CTZAN与Fe(Ⅲ)形成一种稳定的络合比为2:1的紫红色络合物,最大吸收波长位于570 nm处,络合物的表观摩尔吸光系数为2.08×104 L·mol-1·cm-1,Fe(Ⅲ)质量浓度在(0.08～0.8)μg/ mL范围内符合比尔定律.所拟方法不经分离直接测定纯铝和铝合金样品中微量的铁,测定结果与认定值相符.     

流动注射催化光度法同时测定铁和锰

基于铁(Ⅲ)和锰(Ⅱ)对高碘酸钾氧化罗丹明B褪色的催化作用及在不同反应条件下二者催化作用的差异，以反应条件作为化学计量学中的量测通道，应用岭回归法对铁(Ⅲ)和锰(Ⅱ)同时测定进行了研究，建立了流动注射催化光度法同时测定铁和锰的方法。在铁(Ⅲ)和锰(Ⅱ)浓度比为1：4——2：1的范围内，应用该法对其混合物进行测定，田收率分别为101．2％和101．1％。     

新显色剂2-（5-羧基-1，3，4-三氮唑偶氮）-5-二乙氨基苯甲酸与铁的显色反应

研究了新显色剂2-(5-羧基-1,3,4-三氮唑偶氮)-5-二乙氨基苯甲酸(简称CTZDBA)与铁的显色反应。结果表明,在pH4.0的HAc-NaAc缓冲溶液中,CTZDBA与Fe(Ⅲ)形成稳定的络合比为2∶1的紫红色络合物,最大吸收波长为560nm,络合物的表观摩尔吸光系数为2.21×104L.mol-1.cm-1,Fe(Ⅲ)质量浓度在(0～0.8)mg/L范围内符合比尔定律。所拟方法不经分离直接测定纯铝和铝合金样品中微量的铁,测定结果与认定值相符。     

铑-钨酸盐-番红花T缔合显色反应的研究及应用

在聚乙烯醇(PVA)存在下,铑(Ⅲ)与钨酸盐及番红花T(ST)形成的离子缔合物在480nm处产生最大吸收.据此建立了测定铑(Ⅲ)的光度分析方法,其表观摩尔吸光系数ε达108L·mol-1·cm-1数量级.方法的检测范围为0.15～1.5 ng/25ml.大量存在的常见离子对Rh(Ⅲ)的测定不干扰.用此方法测定了催化剂及工业产品中铑的含量,结果与标准方法(SnCl2法)一致.     

测定逐级络合物稳定常数的等色点——平衡移动法

本文将平衡移动法应用于逐级络合物稳定常数的测定,对相互交错严重的逐级络合反应,利用计算机自动寻找严格的实验条件,使系列溶液吸收光谱形成等色点,以判断反应进程,从而将复杂的逐级平衡分解.方法简便可靠,实验条件严谨,用以测定经典的铁-磺基水杨酸体系,取得了满意的结果.     

三聚磷酸二氢铁的制备、性能及应用研究

本文以Fe_2O_3或Fe(OH)_3为原料与H_3PO_4(85％)反应,经中和、溶解和聚合,当P_2O_5/Fe_2O_3(R)≥5,T=250～280℃时,得非晶态三聚磷酸二氢铁(FeH_2P_3O_(10)·2H_2O),T>280℃时,得结晶态的FeH_2P_3O_(10)·2H_2O。FeH_2P_3O_(10)·2H_2O的脱水过程为, FeH_2P_3O_(10)·2H_2O是很好的无毒防锈颜料。     

Structure and reactivity of a mononuclear non-haem iron(III)-peroxo complex

Oxygen-containing mononuclear iron species--iron(III)-peroxo, iron(III)-hydroperoxo and iron(IV)-oxo--are key intermediates in the catalytic activation of dioxygen by iron-containing metalloenzymes. It has been difficult to generate synthetic analogues of these three active iron-oxygen species in identical host complexes, which is necessary to elucidate changes to the structure of the iron centre during catalysis and the factors that control their chemical reactivities with substrates. Here we report the high-resolution crystal structure of a mononuclear non-haem side-on iron(III)-peroxo complex, [Fe(III)(TMC)(OO)](+). We also report a series of chemical reactions in which this iron(III)-peroxo complex is cleanly converted to the iron(III)-hydroperoxo complex, [Fe(III)(TMC)(OOH)](2+), via a short-lived intermediate on protonation. This iron(III)-hydroperoxo complex then cleanly converts to the ferryl complex, [Fe(IV)(TMC)(O)](2+), via homolytic O-O bond cleavage of the iron(III)-hydroperoxo species. All three of these iron species--the three most biologically relevant iron-oxygen intermediates--have been spectroscopically characterized; we note that they have been obtained using a simple macrocyclic ligand. We have performed relative reactivity studies on these three iron species which reveal that the iron(III)-hydroperoxo complex is the most reactive of the three in the deformylation of aldehydes and that it has a similar reactivity to the iron(IV)-oxo complex in C-H bond activation of alkylaromatics. These reactivity results demonstrate that iron(III)-hydroperoxo species are viable oxidants in both nucleophilic and electrophilic reactions by iron-containing enzymes.     

酚藏花红——二苯胺磺酸钠双指示剂重铬酸钾容量法测定矿石中铁

本文研究了以酚藏花红为内指示剂,三氯化钛还原铁,以二苯胺磺酸钠为指示剂,重铬酸钾容量法测定矿石中铁。方法准确,稳定,操作简便并消除了汞对环境的污染。     

近红外花菁染料用于痕量铁的分光光度法测定

在稀硫酸介质中，痕量铁(Ⅲ)对磺酸基阴离子花菁在770nm处的长波吸收具有明显的减色效应．最佳条件下，降低的吸收峰强度与铁(Ⅲ)的浓度间呈现良好的线形关系，从而建立了近红外测定痕量铁的分光光度新方法．线性范围为5—30ng／mL，检测限为4．8ng／mL，对15ng／mL的铁标准液进行7次平行测定，相对标准偏差为4．0％．该法具有红区测量光谱干扰小的优点，用于铝合金样品中铁含量测定，结果令人满意．     

Maize yellow stripe1 encodes a membrane protein directly involved in Fe(III) uptake

Frequently, crop plants do not take up adequate amounts of iron from the soil, leading to chlorosis, poor yield and decreased nutritional quality. Extremely limited soil bioavailability of iron has led plants to evolve two distinct uptake strategies: chelation, which is used by the world's principal grain crops; and reduction, which is used by other plant groups. The chelation strategy involves extrusion of low-molecular-mass secondary amino acids (mugineic acids) known as 'phytosiderophores' which chelate sparingly soluble iron. The Fe(III)-phytosiderophore complex is then taken up by an unknown transporter at the root surface. The maize yellow stripe1 (ys1) mutant is deficient in Fe(III)-phytosiderophore uptake, therefore YS1 has been suggested to be the Fe(III)-phytosiderophore transporter. Here we show that ys1 is a membrane protein that mediates iron uptake. Expression of YS1 in a yeast iron uptake mutant restores growth specifically on Fe(III)-phytosiderophore media. Under iron-deficient conditions, ys1 messenger RNA levels increase in both roots and shoots. Cloning of ys1 is an important step in understanding iron uptake in grasses, and has implications for mechanisms controlling iron homeostasis in all plants.     

氯盐溶液预氧化—针铁矿法除铁过程的研究

通过试验,对锌、锰氯化物溶液中预氧化—针铁矿法除铁过程进行了研究,探索了在软锰矿作氧化剂和锌焙砂作中和剂等条件下,预氧化过程和针铁矿沉铁过程同槽同时进行的工艺可行性,考察了温度、时间、氧化剂MnO_2量和溶液酸度等因素对预氧化的作用效果、除铁效果以及渣的过滤性能等指标的影响。研究结果表明:氯盐溶液中预氧化—针铁矿法同槽同时除铁过程不仅工艺可行,而且在一定的条件下能获得非常满意的除铁效果。     

Photochemical cycling of iron in the surface ocean mediated by microbial iron(III)-binding ligands

Iron is a limiting nutrient for primary production in large areas of the oceans. Dissolved iron(III) in the upper oceans occurs almost entirely in the form of complexes with strong organic ligands presumed to be of biological origin. Although the importance of organic ligands to aquatic iron cycling is becoming clear, the mechanism by which they are involved in this process remains uncertain. Here we report observations of photochemical reactions involving Fe(III) bound to siderophores--high-affinity iron(III) ligands produced by bacteria to facilitate iron acquisition. We show that photolysis of Fe(III)-siderophore complexes leads to the formation of lower-affinity Fe(III) ligands and the reduction of Fe(III), increasing the availability of siderophore-bound iron for uptake by planktonic assemblages. These photochemical reactions are mediated by the alpha-hydroxy acid moiety, a group which has generally been found to be present in the marine siderophores that have been characterized. We suggest that Fe(III)-binding ligands can enhance the photolytic production of reactive iron species in the euphotic zone and so influence iron availability in aquatic systems.