共查询到20条相似文献,搜索用时 187 毫秒
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催化动力学光度法测定水中微量锰 总被引:19,自引:0,他引:19
1引言研究了锰(Ⅱ)催化亮绿SF褪色反应的动力学特性。在NaAc-HAc介质中,锰(Ⅱ)对高碘酸钾氧化该试剂的褪色反应具有强烈催化作用,其褪色反应速率与锰(Ⅱ)的浓度在一定范围内呈良好的线性关系。详细研究了亮绿SF催化动力学光度法测定微量锰(Ⅱ)的条件,建立了测定微量锰(Ⅱ)的新方法。有关文献中催化动力学光度法测定锰(Ⅱ)的检出限大多为10-10g/mL,本方法的检出限为6.0×10-11g/mL,选择性较好,方法相对标准偏差2.5%,用于测定水样中的锰,结果满意。2实验部分2.1主要试剂和仪器… 相似文献
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新显色剂2—氯—5—羧基苯基重氮氨基偶氮苯的合成及与镉显色反应的研究 总被引:4,自引:1,他引:4
本报道了新显色剂2-氯-5-羧基苯基重氮氨基偶氮苯的合成。研究了在pH9.8硼砂-氢氧化钠介质中、在Triton X-100存在下镉(Ⅱ)与CCDAA形成稳定的红色配合物,λmax=485nm,ε485=1.24×10^5L.mol^-1·cm^-1,镉量在0 ̄10μg/25mL范围内遵守比尔定律。本法灵敏度高,选择性好,已用于测定工业废水中微量镉(Ⅱ),结果满意。 相似文献
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研究了在35±0.1℃、离子强度0.5mol/L(KCl)条件下,甲酸根、乙酸根、丙酸根和丁酸根分别催化Cu(Ⅱ)离子与四溴化间-四(N-乙酸甲酯基-3-吡啶基)卟啉(H2TB-N-ACMSpyPBr4)的反应动力学及其机理,该类反应对卟啉和Cu(Ⅱ)离子均为一级反应,反应动力学方程为:d[Cup4+]/dt=k{(1.0+b[A-])/(1.0+K3,4·[H+]2)}[Cu2+][p]T,在甲酸-甲酸根缓冲体系中,k=2.98mol-1dm3·sec-1,b=154×102mol-2,dm6·sec-1,K3,4=6.928×103;在乙酸-乙酸根缓冲体系中,k=3.42mol-1·dm3·sec-1,b=2.29×103mol-2·dm6·sec-1,K3,4=6.928×103;在丙酸-丙酸根缓冲体系中,k=3.00mol-1·dm3·sec-1,b=5.90×102mol-2·dm6·sec-1,K3,4=7.007×103;在丁酸-丁酸根缓冲体系中,k=3.14mol-1·dm3·sec-1,b=3.75×102mol-2·dm6·sec-1,K3,4=6.921×103;讨论了有机酸根的碱性与 相似文献
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示波极谱法测定微量锰 总被引:2,自引:0,他引:2
研究了在氨-氯化铵介质中,Mn(Ⅱ)与邻菲罗啉形成络合物并在示波极谱仪上产生一灵敏的吸附还原波的适宜条件和影响因素,建立了测定微量锰的新方法。测定线性范围为5.0×10^-8 ̄5.0×10^-6mol·L^-1,检出下限为2.0×10^-8mol·L^-1,测定了水和酒样中的锰含量,结果满意。 相似文献
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本研究了铍(Ⅱ)与对碘偶氮氯膦的显色反应。在0.1mol/LNaAc 溶液中,铍(Ⅱ)与显色剂生成蓝色配合物。最大吸收波长为620nm,其摩尔吸光系数ε620=3.36×10^4L·mol^-1·cm^-1。铍(Ⅱ)含量在0~5.0μg/25mL范围内经尔定律。配合物中Be(Ⅱ)与显色剂的摩尔比为1∶2。该方法可应用于铍青铜、铝合金及水样中微量铍的测定。方法灵敏、快速、简便。 相似文献
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研究了表面活性剂十二烷基磺酸钠(SDS)存在下,锰(Ⅶ)氧化胭脂红的褪色反应。结果表明,在硫酸介质中,锰(Ⅶ)能够氧化胭脂红褪色,SDS可大幅度提高反应的灵敏度,且氧化褪色程度与锰(Ⅶ)的含量在一定的范围内符合比尔定律。据此建立了表面活性剂增敏、褪色光度法测定锰(Ⅶ)的新方法。锰(Ⅶ)的测定范围为0~4.0μg.mL-1,表观摩尔吸光系数为4.3×104L.mol-1.cm-1,应用于茶叶中锰的测定,结果满意。 相似文献
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催化荧光法测定痕量锰 总被引:4,自引:2,他引:4
本文拟定了一个催化荧光测定痕量锰的新方法。方法检出限为0.0180ng/ml。线性范围为0.04~1.00 ng/ml。直接用于头发、人尿、鱼、水样中锰的测定。回收率为96%~103%,获得满意结果。 相似文献
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This work assesses the potential of a new adsorptive material, Amberlyst 36, for the separation and preconcentration of trace manganese(II) from various media. It is based on the sorption of manganese(II) ions onto a column filled with Amberlyst 36 cation exchange resin, followed by the elution with 5 mL of 3 mol/L nitric acid and determination by flame atomic absorption spectrometry (FAAS) without interference of the matrix. Different factors including pH of sample solution, sample volume, amount of resin, flow rate of sample solution, volume and concentration of eluent, and matrix effects for preconcentration were investigated. Good relative standard deviation (3%) and high recovery (>95%) at 100 μg/L and high enrichment factor (200) and low analytical detection limit (0.245 μg/L) were obtained. The adsorption equilibrium was described well by the Langmuir isotherm model with maximum adsorption capacity of 88 mg/g of manganese on the resin. The method was applied for the manganese determination by FAAS in tap water, commercial natural drinking water, commercial treated drinking water and commercial tea bag sample. The accuracy of the method is confirmed by analyzing the certified reference material (tea leaves GBW 07605). The results demonstrated good agreement with the certified values. 相似文献
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An on-line cloud point extraction system for flame atomic absorption spectrometric determination of trace manganese in food samples 总被引:1,自引:0,他引:1
The development of an on-line preconcentration system with cloud point extraction for the determination of manganese is described. The system was used to determine manganese levels in food samples using flame atomic absorption spectrometry (FAAS). All steps of the cloud point extraction procedure were performed on-line, from the mixing of reagents to detection. The manganese ions are complexed in a mixture of the reagent 2-[2′-(6-methyl-benzothiazolylazo)]-4-bromophenol (Me-BTABr) and Triton X-114. The components are retained on a minicolumn and then desorbed with eluent acid to subsequent detection of manganese by FAAS. Under the optimized conditions, the method presented a detection limit of 0.7 μg L− 1 and an enrichment factor of 17 to a volume of 3000 μL. The sampling frequency was 30 h− 1. The accuracy of the method was tested by evaluating the amount of Mn in certified reference materials (apple leaves NIST 1515 and spinach leaves NIST 1570a). The proposed procedure was applied to food samples (shrimp powder, flaxseed flour, wheat flour, soy flour and oat), and the results agreed with those obtained by the determination of Mn in foods by atomic absorption spectrometry with electrothermal atomization (ETAAS). 相似文献
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《Journal of computational chemistry》2017,38(20):1747-1751
The present contribution assesses the performance of several popular and accurate density functionals, namely B3LYP, BP86, M06, MN12L, mPWPW91, PBE0, and TPSSh toward manganese‐based coordination complexes. These compounds show promising properties toward application to catalytic water oxidation. Although manganese with N‐ and O‐biding ligands tends to give rise to high spin complexes, the results show that BP86, mPWPW91, and specially MN12L, tend to yield low‐spin complexes. The usage of these functionals for such compounds is, thus, discouraged. All the functionals considered deliver accurate geometries. The present results show, however, that B3LYP delivers geometries deviating from experimental values when compared to the other functionals of the set. M06, PBE0, and TPSSh deliver geometries of similar accuracy, PBE0 outstanding slightly with respect to the other two. © 2017 Wiley Periodicals, Inc. 相似文献
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研究了在阳离子表面活性剂溴化十六烷基三甲胺(CTAB)存在下,2,3,7-三羟基-9-(3,5-二氯)水杨基荧光酮(DCSAF)与Mn2+的显色反应和光谱性能。结果表明,在pH=9.07的Na2HPO4-KH2PO4缓冲溶液中,Mn2+与DCSAF形成摩尔比为1∶2的三元配合物。该配合物最大吸收峰位于550nm处,表观摩尔吸光系数ε=1.92×105L.mol-1.cm-1,Mn2+含量在0~0.70μg/5mL范围内符合比耳定律。建立的分析方法用于钢样中微量Mn2+的测定,结果令人满意。 相似文献
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Ferreira SL Souza AS Brandao GC Ferreira HS dos Santos WN Pimentel MF Vale MG 《Talanta》2008,74(4):699-702
A procedure is proposed for the direct determination of manganese and iron in wine employing fast sequential flame atomic absorption spectrometry and the reference element technique to correct for matrix effects. Cobalt, silver, nickel and indium have been tested as reference elements. The results demonstrated that cobalt and indium at a concentration of 2 and 10mgL(-1) were efficient for quantification of manganese and iron, respectively. Under these conditions, manganese and iron could be determined with quantification limits of 27 and 40microg L(-1), respectively. The proposed method was applied to the determination of manganese and iron in 16 wine samples. The content of manganese varied from 0.78 to 2.89mgL(-1) and that of iron from 0.88 to 9.22mgL(-1). The analytical results were compared with those obtained by inductively coupled plasma optical emission spectrometry after complete mineralization using acid digestion. The statistical comparison by a t-test (95% confidence level) showed no significant difference between the results. 相似文献
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Marta Knap 《Talanta》2007,71(1):406-410
An on-line preconcentration procedure for the determination of manganese using flow-injection approach with flame atomic absorption spectrometry as a detection method is described. The proposed method is based on the complexation between Mn(II) and 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP). Two approaches were investigated for enrichment of manganese; the formation of Mn-TCPP complex in a solution followed by its retention on a sorbent and the sorption of manganese ions onto the TCPP-modified resin. The best results was obtained for the first approach when 10−5 M reagent was on-line mixed with an aqueous sample solution and passed through the microcolumn packed with anion-exchange resin Amberlite IRA-904 for 5 min. The sorbed complexes were then eluted with 0.5 ml of 2 M HNO3. A good precision (2.2-3.1% R.S.D. for 50 μg l−1 manganese) and the enrichment factor of 30 were obtained with the detection limit of 12 μg l−1 for 5 min loading time. The interference of anions and cations has been studied to optimize the conditions and the method was applied for determination of manganese in natural water samples. The results obtained by FI-FAAS and ETAAS (as a reference method) were not statistically different for a significance level of 0.05. 相似文献
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合成了新型5-氟尿嘧啶修饰的自由卟啉5-(2-(5-氟尿嘧啶-3-基)乙氧基苯基)-10,15,20-三苯基卟啉(L)及其锰配合物(MnL)和锌配合物(ZnL)。通过紫外-可见光谱、红外光谱、核磁共振氢谱及高分辨质谱等手段进行了结构表征。研究了它们的荧光性质和电化学性质;应用标准磺酰罗丹明B法(SRB法)测试了目标化合物对人肺癌细胞株A549、人肝癌细胞株Bel-7402和人结肠癌细胞株HCT-8生长的抑制活性。结果表明:相同实验条件下,不同金属离子对配合物的荧光强度存在较大影响:锌配合物具有荧光猝灭的性质,而锰配合物未能观察到明显的荧光发射光谱;与自由卟啉和锌配合物相比,锰配合物除卟啉环发生氧化还原反应外,Mn~(2+)自身也发生了氧化还原反应;抗癌活性测试显示锰配合物较其他2种化合物有较好的抗癌活性。 相似文献
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Berggren G Huang P Eriksson L Styring S Anderlund MF Thapper A 《Dalton transactions (Cambridge, England : 2003)》2010,39(45):11035-11044
In this work we report the synthesis of two novel manganese complexes, [L1(3)Mn(II)(6)](ClO(4))(6) (1·(ClO(4))(6)) and [L2Mn(II)(2)(μ-OAc)(μ-Cl)](ClO(4))(2) (2·(ClO(4))(2)), where L1(2-) is the 2,2'-(1,3-phenylenebis(methylene))bis((2-(bis(pyridin-2-ylmethyl)amino)ethyl)azanediyl)diacetic acid anion and L2 is N1,N1'-(1,3-phenylenebis(methylene))bis(N2,N2'-bis(pyridin-2-ylmethyl)ethane-1,2-diamine). The ligands Na(2)L1 and L2 are built on the same backbone, L2 only contains nitrogen donors, while two carboxylate arms have been introduced in Na(2)L1. The two complexes have been characterized by single-crystal X-ray diffraction, magnetic susceptibility, EPR spectroscopy, and electrochemistry. X-Ray crystallography revealed that 1 is a manganese(II) hexamer and 2 is a manganese(II) dimer featuring an unprecedented mono-μ-acetato, mono-μ-chlorido bridging motif. The ability of the complexes to catalyse H(2)O(2) disproportionation, thereby acting as models for manganese catalases, has been investigated and compared to the activity of two other related manganese complexes. The introduction of carboxylate donors in the ligands, leading to increased denticity, resulted in a drop in H(2)O(2) disproportionation activity. 相似文献