火焰原子吸收光谱法测定铜冶炼渣中镍

通过对铜冶炼渣化学组成和性质的研究,确定了测定镍的实验方法。铜冶炼渣中二氧化硅含量在20%~40%,硫含量10%~20%,样品的分解具有一定的难度,必然影响镍的测定结果,因此需在样品分解过程中加入一定量的氟化氢铵、溴使二氧化硅生成四氟化硅、硫生成硫化氢挥发除去,溶液中其余共存元素主要有铜、银、铁、锌等元素不干扰测定结果,在硝酸(5%)介质中,用火焰原子吸收光谱法测定镍的含量,测定范围为0.01%~1%,加标回收率在99.5%~100.4%,测定结果的相对标准偏差(n=7)在0.61%~1.18%,检出限为0.004μg/mL,方法快速,简捷,能够满足日常生产检测需要。     

稀土湿法冶炼废渣中氡的放射性及其测定方法

基于稀土矿石中伴生的钍(Th)、铀(U)、镭(Ra)等天然放射性核素在湿法冶炼过程中富集于废渣,它们衰变可释放出氡(Rn)。以活性炭吸附、二甲苯闪烁液静态和动态吸收3种方法捕集Rn,应用液闪系统测定了两种稀土湿法冶炼废渣中Rn的放射性活度。测量结果表明,废渣中Rn的放射性比活度(Bq.kg-1)表现出较高水平,且在不同废渣中具有明显差异,为综合评估稀土厂"三废"的放射性及其危害性提供了依据;从3种方法的比较分析,提出了以二甲苯闪烁液静态吸收后用液闪法测定Rn的程序。     

阳极溶出伏安法测定镍的椭圆法研究

阳极溶出伏安法测定镍的椭圆法研究①朱伟杨雨如黄宗卿＊（重庆大学应用化学系重庆４０００４４）电极表面准单分子层上发生的物理或化学变化能使入射的椭圆偏振光的光学参量发生明显的变化，理论分析和实验测定均表明椭圆法可灵敏地提供电极表面０．１ｎｍ厚度层内发生变...     

火焰原子吸收光谱法测定不锈钢中高含量镍

镍的火焰原子吸收光谱法的测定已有报道,在测定中大多采用232.0 nm吸收线。光谱分析波长适合于微量镍的测定,但不适于不锈钢中高含量镍的测定。国家标标准GB/T 223.25—1994方法对不锈钢中镍的测量范围为0.030%～2.00%,不适合应用于样品中镍含量大于2%的样品的测定,应选用丁二酮肟重量法和EDTA滴定法测定镍量,操作繁琐,耗时长。针对此问题,本工作采用火焰原子吸收光谱法,采用镍341.5 nm次灵敏线测定不锈钢中高含量镍,样品经盐酸-硝酸-水(3+1+12)溶液溶解后定     

石墨炉原子吸收法测定食品中镍的研究

建立了测定食品中镍的石墨炉原子吸收法，方法的最低检出限为１．６０μｇ／Ｌ，标准参考物牡蛎镍的测定值怀保证值偏差小于５％，回收率在８６．０％￣１０３．０％之间，并对我国八大类食品中镍含量本底值作了调查。     

酒石酸掩蔽铝-丁二酮肟重量法测定镍钴铝三元氢氧化物中镍

镍钴铝三元氢氧化物中Ni质量分数为45%~60%、Al为0.5%~1.5%,丁二酮肟沉淀镍的pH条件下,Al3+会水解沉淀而干扰测定。试验对丁二酮肟重量法进行改进,采用酒石酸作为Al的掩蔽剂,从而建立了酒石酸掩蔽铝-丁二酮肟重量法测定镍钴铝三元氢氧化物中Ni含量的方法。试验评价了Al对丁二酮肟重量法测Ni的干扰,并确定了酒石酸的最佳掩蔽用量,测定实际样品801505型镍钴锰三元氢氧化物（Ni0.8Co0.15Al0.05(OH)2）和851005型镍钴锰三元氢氧化物（Ni0.85Co0.1Al0.05(OH)2）的RSD（n=11）分别为0.24%、0.31%,加标回收率分别为100.20%、99.68%,且测定值与ICP-AES基本一致。     

在线红外水分仪的一种校准方法

用动态被测物料作为校准介质,再用重量法对选取的样品定值,以此校准在线红外水分仪。     

火焰原子吸收光谱法测定铜冶炼烟尘中铋

本文研究了测定铜冶炼烟尘中铋含量0.050% ~5.00%的火焰原子吸收光谱法。对铜冶炼烟尘试样的溶解、测定体系中酸介质的影响和各干扰元素进行了试验研究。制定了铜冶炼烟尘中铋含量的原子吸收光谱法。方法标准偏差为0.0013 %~ 0.057 %,相对标准偏差为0.78 % ~1.44 %,样品加标回收率为98.95%~101.87%。本方法具有灵敏度高、结果准确、操作简便等特点,适合铜冶炼烟尘中铋含量0.050 % ~ 5.00 % 的测定。     

New understanding of aconitine hydrolysis pathway: Isolation,identification and toxicity evaluation based on intermediate products

Aconitine hydrolysis is deemed to be the guarantee for the safe application of Aconitum phytomedicine. Studies have suggested that hydrolysates of aconitine not only include benzoylaconitine and aconine, but other hydrolysates. Moreover, these hydrolysates maybe have a mutual transformation relationship, which has not been confirmed. Herein, hydrolysates of aconitine and their mutual transformation relationship were studied by the theoretical quantum chemistry, UPLC-Q-TOF-MS, the separation and identification of target products, etc. Then the toxicity of its hydrolysates was evaluated. The results demonstrate that the probability is the same for aconitine hydrolysis to pyroaconitine and benzoylaconitine, but they are difficult to convert to each other. Aconitine hydrolysis has three independent hydrolysis pathways, 1) to indaconitine, 2) to benzoylaconitine, and aconine, 3) to pyroaconitine and to 16-epi-pyroaconine. The result of embryotoxicity evaluation on zebrafish was aconitine > indaconitine > benzoylaconitine > α-pyroaconitine > β- pyroaconitine > aconine > 16-epi-pyroaconine. In conclusion, aconitine have three independent hydrolysis pathways and the hydrolysates of different pathways cannot be transformed into each other. Pyroaconitine is a hydrolysate of aconitine except for benzoylaconitine, and its toxicity is lower than benzoylaconitine. More importantly, it clarifies the long-standing debate and provides scientific evidence for the processing and detoxification of Aconitum phytomedicine.     

铜冶炼物料中铜的分析质量控制方法综述

目前国内铜精矿供应紧俏,铜冶炼行业的原料复杂,有些偏离了认证和认可标准方法的样品,在检测时,用认证、认可文件不能很好地进行质量管控,需要对分析方法加以改进,从技术上进行管控。结合国内铜冶炼企业的实际情况和多年的实践经验,从样品的加工和保存环节、铜分析的技术环节、人员培训、质量抽查、定期开展质量分析会等方面对铜的分析质量控制进行了总结。在具体的质量控制中,针对铜冶炼行业成分复杂、易变化的物料分析,应根据实际情况进行质量管控,以提高铜分析的准确度。     

Mass spectrometric study of products and intermediate compounds in oscillating chemical reactions of oxidation of macrocyclic copper and nickel complexes by a bromate

Products and intermediate compounds formed in oscillating chemical reactions of oxidation of copper and nickel tetraazamacrocyclic complexes were studied by the method of desorption field mass spectrometry. It was shown that a cascadelike oxidation of the macrocyclic ligand takes place and its hydrolysis with rupture of the macrocyclic ring at the azomethine bonds. Products of bromination of oxygen- and nitrogen-containing compounds, participants in the reactions, were discovered.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 23, No. 2, pp. 221–225, March–April, 1987.     

Mechanism study on UV-induced photodegradation of nonylphenol ethoxylates by intermediate products analysis

Photodegradation of nonylphenol ethoxylates(NP10EO)was investigated in laboratory scale under UV irradiation.Theintermediate photodegradation products were analyzed by LC-ESI-MS.Three kinds of intermediate products including aldehydiccompounds,carboxylic compounds and cyclohexanyl compounds were identified.Five main degradation routes involving theoxidation of the alkyl chain and ethoxylate unit,shortening of the alkyl chain and ethoxylate unit,hydrogenation of the benzene ringwere proposed.     

Multipole expansions of orbital products about an intermediate center

A numerical method described previously (Talman, Int J Quantum Chem, 2007, 107, 1578) is reviewed and a modified formulation that may be more computationally efficient is presented. Modifications required for the application to real harmonics are described. The method requires the numerical evaluation of a one‐dimensional integral on a finite interval, and an improved method for this is described. The application to the evaluation of electron–electron repulsion four‐center integrals is also discussed. It is indicated that μ H accuracy is obtainable with modest computational effort. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

Cold crystallization kinetics of slag from the joint smelting of oxidized nickel and sulfide copper ores

Journal of Thermal Analysis and Calorimetry - The cold crystallization kinetics of the glass-crystal composition (90.3 vol% of glass) made of slag from the joint smelting of oxidized nickel and...     

Photocatalytic degradation of paraquat and genotoxicity of its intermediate products

The photocatalytic degradation of paraquat (1,1-dimethyl-4,4′-bipyridylium dichloride) aqueous solutions in the presence of polycrystalline TiO₂ Degussa P25 irradiated by near-UV light was investigated. The substrate and total organic carbon concentrations were monitored by UV spectroscopy and TOC measurements, respectively: the complete photocatalytic mineralization of paraquat (20 ppm) was achieved after ca. 3 h of irradiation by using 0.4 g l⁻¹ of catalyst amount at natural pH (ca 5.8). On the contrary no significant photodegradation of paraquat was observed in the absence of TiO₂ under similar experimental conditions. To evaluate the genotoxicity of paraquat and its intermediates produced during heterogeneous photocatalytic treatment, in vitro tests such as Ames test, with and without rat liver microsomal fractions (S9 mix), and micronucleus test, were used. Results obtained with Salmonella typhimurium (strain TA100) showed that paraquat and photocatalytic products were unable to induce gene mutations when photocatalysis was used in the presence of the optimum amount of TiO₂, i.e. 0.4 g l⁻¹, whereas an increase of revertants his⁺ per plate was observed after 300 min irradiation in the presence of very low amount of TiO₂ (0.04 g l⁻¹). The negative results from micronucleus test suggest that mutagenic, but non-clastogenic, late intermediates of paraquat photo-oxidation were formed when the photocatalytic runs of paraquat degradation were carried out by using 0.04 g l⁻¹ of photocatalyst.