共查询到19条相似文献,搜索用时 453 毫秒
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阳离子交换树脂分离-铝试剂分光光度法测定土壤中铝形态 总被引:4,自引:0,他引:4
研究了铝试剂光度法测定土壤溶液中铝的最佳条件,着重探讨了共存离子,特别是土壤溶液中的无机离子和有机阴离子对测定铝的影响。采用阳离子交换树脂分离,建立了测定土壤溶液及天然水中铝形态方法。用该法可测定总反应性铝、总单核铝和稳定性单核铝。由总反应性铝减去总单核铝求得酸溶性铝。由总单核铝减去稳定单核铝求得不稳定单核铝。与阳离子树脂交换分离-邻苯二酚紫光度法进行了比较。结果表明:邻苯二酚紫光度法灵敏度较高,但铁的干扰较大。铝试剂光度法灵敏度略低,但铁的干扰较少。阳离子树脂交换分离-铝试剂光度法更适合于测定含铁量比较高的土壤溶液中的铝形态。 相似文献
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本文报道酸性媒染紫(SVRS)一示波计时电位法测定天然水中不同形态铝。对24个实际水样分别在酸性pH5.2测定了无机单核铝Ali和碱性pH8.8底液中测定总单核铝Ala,有机单核铝Al0-Ala-Alio同时还应用该法测定了酸化水样中总铝AlT,酸溶态铝AlT=AlT-Ala,从而实现了水样中五种形态铝的电化学测定,测定值与Driscoll方法进行了比较对照,结果基本一致。本法特点为:简便快捷,灵敏准确,可以直接测定与铝毒性密切相关的无机单核铝Ali,无需分离步骤,水样用量小,适用于大批量天然水样中Al形态的快速分析。 相似文献
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酸性媒染紫一示波计时电位法测定天然水不同形态铝 总被引:3,自引:0,他引:3
本文报道酸性媒染紫(SVRS)一示波计时电位法测定天然水中不同形态铝.对24个实际水样分别在酸性pH5.2测定了无机单核铝Ali和碱性pH8.8底液中测定总单核铝A1a,有机单核铝Al.=A1a-Ali.同时还应用该法测定了酸化水样中总铝AlT,酸溶态铝Alr=AlT-A1a,从而实现了水样中五种形态铝的电化学测定.测定值与DriSColl方法进行了比较对照,结果基本一致.本法特点为简便快捷,灵敏准确,可以直接测定与铝毒性密切相关的无机单核铝A1i,无需分离步骤,水样用量小,适用于大批量天然水样中Al形态的快速分析. 相似文献
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流动注射胶束增溶分光光度法同时测定镁砖中微量铁铝 总被引:5,自引:1,他引:5
本文研究了铁铝-CAS-乳化剂OP胶束增溶体系的FIA-光度法时测定镁砖中微量铁铝,该法操作简便,快速可靠,进样频率45样次/h,RSD<3.4%和5.8%。结果令人满意。 相似文献
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报道了采用铬蓝黑R(EBBR)-示波计时电位法分别在酸性和碱性条件下直接检测天然水中的无机单核铝[Ali]和总单核铝[Ala]浓度.并用该法测定了酸消化水样中的总铝[AlT],由[Ala]-[Ali]间接得到有机单核[Alo],[AlT]-[Ala]得到酸溶态铝[Alr],从而实现了水中5种Al形态的电化学测定.实验条件和结果如下在碱性pH=8.0的0.5 mol*L-1 KCl+0.1 mol*L-1 Na2B4O7缓冲溶液中, EBBR切口为Ep1= -0.60 V,加入铝后出现新切口,Ep2=-1.05 V,检测线性范围为5×10-7~7×10-5 mol*L-1,检测下限为2×10-7 mol*L-1,在5× 10-6 mol*L-1 Al时相对标准偏差为4.6% (n=10).分别在酸性和碱性条件下测定了水样中的铝浓度,发现在酸性下测定的是无机单核铝,而在碱性下则是总单核铝(包括无机单核铝和有机单核铝两部分).据此实现了对铝形态的区分,测定了20多个实际水样,与Driscoll方法所获结果进行对照,结果基本一致. 相似文献
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新显色剂二甲氧基羟基苯基荧光酮双波长分光光度同时测定铝和铁的研究 总被引:4,自引:0,他引:4
研究了新显色剂二甲氧基羟基苯基荧光酮(DMH-PF)双波长分光光度同时测定铝和铁的新方法。在氨性介质中,氟化钠及Triton X-100 存在下,铝、铁与试剂分别形成红色和紫色配合物,最大吸收波长分别为547 nm 和578 nm 。选定铝的测定波长对为547~615.5 nm ,铁的测定波长为610 nm ,表观摩尔吸收系数ε547Al = 1.67×105 L·m ol- 1 ·cm - 1,ε610Fe = 8.30×104 L·m ol- 1·cm - 1,0~3 μg Al3+ /25m L和0~6 μg Fe3+ /25m L范围内符合比耳定律。应用于工业硅中铝和铁的同时测定,获得满意结果。 相似文献
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铝—酸性铬蓝K荧光光度法测定微量铝的研究 总被引:5,自引:1,他引:5
研究了酸性铬蓝K(ACBK)荧光光度法测定微量铝的反应。Al^3+与ACBK形成络合物的荧光强度与铝的含量在1×10^-8~8×10^-6mol/L范围内呈现良好的线性关系,检测限为4.8×10^-9mol/L,对4×10^-8mol/L铝重复11次检测其相对标准偏差为4.8%,成功地用于人发及钢样中铝含量的测定。 相似文献
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提出了同时测定铜基合金中铝和铁的流动注射分析法。以0.04mol/LHCl作载液,铬天青S为显色剂,通过测定628nm处铝、铁两配合物的吸光度之和及铝配合物的吸光度,实现了两组分的同时测定。在优化的实验条件下,检测限:Al和Fe分别为1.69×10-3和1.73×10-3mg/L,Al浓度在0~0.8mg/L;Fe浓度在0~1.0mg/L时服从比耳定律。进样频率为60样/h,所拟方法用于实际样品分析,获得满意结果。 相似文献
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《Analytical letters》2012,45(7):1435-1446
ABSTRACT A simple and sensitive electrochemical method for the direct determination of labile (monomeric inorganic Al speciation) Al concentration in natural waters is developed in this paper. It is based on the use of a.c. oscillopolarography in the presence of rubeanic acid (RA). The optimal experimental conditions are: 1 mol/L NaAc-HAc buffer (pH 5.4) and a RA concentration of 6x10?4 mol/L. The response is linear over the 2x10?7 to 2x10?6 mol/L concentration range. The detection limit is 1x10?7 mol/L and the relative standard deviation (at the 1.2 x 10?6 mol/L level) is 5.5%. The method has been applied to the direct determination of labile monomeric Al concentrations in various natural samples. The results were verified by the classic ion exchange method. 相似文献
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The coordination number of the gadolinium atom and bond distances in the crystal of inonomeric porphyrinate,[Gd(TPP)acac-8H2O 3TCB] (TCB: 1,2,4-trichlorobenzene,acac: anion of acetylacetone),were determined by EXAFS method.The Gd atom is eight-coordinated to the four nitrogen atoms of a tetraphenylporphyrin ring,to the two oxygen atoms of one acetylacetonato anion and to two water molecules with Gd-N=0.232 nm,Gd-O=0.243 nm. 相似文献
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Jodi M. Milhaupt Bryan R. Chapman Timothy P. Lodge Steven D. Smith 《Journal of polymer science. Part A, Polymer chemistry》1998,36(17):3079-3086
Monomeric friction factors, Ξ, for polystyrene (PS), polyisoprene (PI), and a polystyrene–polyisoprene (SI) diblock copolymer have been determined as a function of temperature in four poly(styrene-b-isoprene-b-styrene-b-isoprene) tetrablock copolymer matrices. The Rouse model has been used to calculate the friction factors from tracer diffusion coefficients measured by forced Rayleigh scattering. Within the experimental temperature range the tetrablock copolymers are disordered, allowing for measurement of the diffusion coefficient in matrices with average compositions determined by the tetrablock copolymers (23, 42, 60, and 80% styrene by volume). Remarkably, for a given matrix composition the styrene and isoprene friction factors are essentially equivalent. Furthermore, at a constant interval from the system glass transition temperature, Tg, all of the friction factors (obtained from homopolymer, diblock copolymer, and tetrablock copolymer dynamics) agree to within an order of magnitude. This is in marked contrast to results for miscible polymer blends, where the individual components generally have distinct composition dependences and magnitudes at constant T − Tg. The homopolymer friction factors in the tetrablock matrices were systematically slightly higher than those of the diblock, which in turn were slightly higher than those of the homopolymers in their respective melts, when all compared at constant T − Tg. This is attributed to the local spatial distribution of styrene and isoprene segments in the tetrablocks, which presents a nonuniform free energy surface to the tracer molecules. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 3079–3086, 1998 相似文献
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Masafumi Unno Hiroyuki Murakami Satoshi Kagawa Hideyuki Matsumoto 《Silicon Chemistry》2007,3(3-4):195-198
Two new silanols bearing very bulky silyl groups, (i-Pr3
Si)3SiOH and (t − BuMe2Si)3SiOH were prepared by peracidoxidation of their respective silanes. The X − ray crystallographic analysis revealed that (t − BuMe2Si)3 SiOH forms a dimeric structure with hydrogen bonding, while (i − Pr3 Si)3 SiOH exists as a monomer in the crystal. The effects of the size of the substituents as well as the reactivity of these silanols
are discussed. 相似文献
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Monomeric emulsifiers with different copolymerization reactivities were used as stabilizers in emulsion polymerization of styrene initiated by 2,2′ azobisisobutyronitrile (AIBN). A significant change in emulsifier function was observed between equal micellar concentrations of surface-active sodium sulfopropyl alkyl maleates and the corresponding sodium sulfopropyl dodecyl fumarate. In the presence of less reactive maleates, copolymerization mainly occurs in the interface of the monomer swollen particles, while copolymerization with the fumarate in the first period of emulsion polymerization leads to polyelectrolyte formation in the water phase. 相似文献
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The complexation behaviour of copper(II) with a series of selected dihydroxycoumarins has been studied. Copper(II) binary
complexes with esculetin, daphnetin and their 4-methyl and 4-phenyl derivatives and ternary complexes having a secondary ligand,
ammonia or pyridine have bean synthesized. The general composition of binary complexes has bean found to be [Cu (H2O)2 (HL)2] and that of ternary complexes as [Cu (L) (X)4] (where X = NH3 or C5H5N). The magnetic studies indicate all the complexes to be monomeric in nature. IR studies show that one of the two phenolic
hydroxyl groups present in the ligand is lost during complexation. It is concluded that of the four ligands attached to the
copper atom dihydroxycoumarin is bound most firmly. 相似文献
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The crystal structures of two monomeric copper(II) carboxylates with 2-aminopyridine have been determined by X-ray diffraction. The hexanoate complex crystallizes as its acetonitrile solvate [Cu(C6H11O2)2(C5H6N2)2 · CH3CN] in the triclinic space group P-1 with a = 8.1020(6), b = 13.7106(9), c = 13.7673(9) Å, = 113.79(1), = 103.86(1), and = 94.38(4). The heptanoate compound shows an unsolvated structure [Cu(C7H13O2)2(C5H6N2)2] and also crystallizes in the triclinic space group P-1 with the following cell parameters: a = 8.4487(9), b = 12.238(1), c = 13.504(2) Å, = 87.034(9), = 77.489(9), and = 71.41(1)°. Both compounds contain the CuO4N2 chromophore, with ligands arranged around the copper center in a cis mode. 2-Aminopyridine is coordinated through the endocyclic nitrogen atom. The ortho position of the amino group, with respect to the pyridine nitrogen atom, allows the formation of both, intra-and intermolecular hydrogen bonds. 相似文献
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Rohit Kumar Dr. Sayan Dutta Vishal Sharma Praval P. Singh Dr. Rajesh G. Gonnade Prof. Debasis Koley Dr. Sakya S. Sen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(56):e202201896
In this work, two monomeric magnesium alkyl complexes ( 1 and 2 ) were prepared using bis(phosphino)carbazole framework and among them 1 has been used as a catalyst for hydroboration of alkenes and alkynes with pinacolborane (HBpin). A broad variety of aromatic and aliphatic alkenes and alkynes were efficiently reduced. Anti-Markovnikov regioselective hydroboration of alkenes and alkynes was achieved, which was confirmed by deuterium-labelling experiments. The work represents the first example of the use of magnesium in homogeneous catalytic hydroboration of alkene with broad substrate scope. Experimental mechanistic investigations and DFT calculations provided insights into the reaction mechanism. Finally, the hydroboration protocol was extended to terpenes. 相似文献
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Dr. Sudipta Roy Christian J. Schürmann Totan Mondal Dr. Debasis Koley Dr. Regine Herbst‐Irmer Prof. Dr. Dietmar Stalke Prof. Dr. Herbert W. Roesky 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(36):12629-12633
Platinum dichalcogenides have been known to exhibit two‐dimensional layered structures. Herein, we describe the syntheses, isolation, and characterization of air‐stable crystalline cyclic alkyl(amino) carbene (cAAC)‐supported monomeric platinum disulfide three‐membered ring complex [(cAAC)2Pt(S2)] ( 2 ). The highly reactive platinum(0) [(cAAC)2Pt] complex ( 1 ) with two‐coordinate platinum activates elemental sulfur to give 2 . The brown crystals of bis‐carbene platinum(II)monosulfate [(cAAC)2Pt(SO4)x(S2)1?x] ( 4 ) have been isolated when the reaction was performed in air. The dioxygen analogue of 2 was formed upon exposing the THF solution of 1 to aerial oxygen (O2). The binding of oxygen at the Pt0 center was found to be reversible. Additionally, DFT study has been performed to elucidate the electronic structure and bonding scenario of 2 , 3 , and 4 . Quantum chemical calculations showed donor–acceptor‐type interaction for the Pt?S bonds in 2 and Pt?O bonds in 3 and 4 . 相似文献