共查询到20条相似文献,搜索用时 62 毫秒
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双流路互不干扰流动注射在线同时测定水中硝酸盐氮和亚硝酸盐氮 总被引:1,自引:0,他引:1
将镀铜镉柱应用于流动注射(FIA)实现了水中硝酸盐氮和亚硝酸盐氮的同时测定。在磷酸介质中,亚硝酸盐与磺胺重氮化,再与N-(1-萘基)-乙二胺盐酸盐偶合,形成玫瑰红色的偶氮染料,在540nm的波长处检测。硝酸盐被镉柱在线还原为亚硝酸盐后同法测定。硝酸盐和亚硝酸盐的测定范围分别为0.1~35mg/L、0~1200μg/L,检出限分别为45.6μg/L和4.8μg/L,RSD均低于1.05%(n=11),测定频率为10样/小时。实际水样中硝酸盐和亚硝酸盐的测定取得了满意的效果,加标回收率均在89.2%~109.0%之间,该仪器适合于现场即时监测。 相似文献
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食物中微量元素硒的分析方法研究进展 总被引:3,自引:0,他引:3
就国内近年来对食物中微量元素硒的分析方法研究进展作一综述。包括:分光光度法,荧光光光度法、原子吸收分光光度法,电感耦合等离子体发射光谱法、极谱法、色谱法和中子活化法。 相似文献
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薄层扫描仪是用于进行薄层扫描定量分析的仪器。虽然它的操作方法、设备等在其30多年的历史中已有许多改进,但整个应用过程是不连续的,且较为复杂,每个操作步骤都会影响定量的准确性。因此,它的使用范围受到一定限制。相比之下,分光光度计的使用要简单得多,它可对液体样品直接分析,具有较好的分析灵敏度和精密度,可测元素较多,操作快速简单。鉴于薄层扫描仪与UV/VIS分光光度 相似文献
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应用水解还原铁(Ⅲ)—邻二氮菲光度法测定丙酮肟 总被引:1,自引:0,他引:1
丙酮肟在酸性条件下经加热水解生成个有还原性的羟胺,并将Fe(Ⅲ)定量还原为Fe(Ⅱ),应用Fe(Ⅱ)-邻二氮菲光度法简接测定丙酮肟。选择了水解最佳条件(加热温度、时间、介质酸度、显以剂的加入顺序等)。结果表明,测定线性范围为0 ̄1.2mg/L。相关系数r=0.9998,最低检测浓度为0.046mg/L,RSD〈3.3%(n=5)。应用该法测定火力发电厂锅炉运行水中丙酮肟的含量,方法简便,灵敏度高。 相似文献
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Brough P Pécaut J Rassat A Rey P 《Chemistry (Weinheim an der Bergstrasse, Germany)》2006,12(19):5134-5141
The chemistry of 2,2,4,4-substituted pentane derivatives has been investigated with the aim of providing a flexible and versatile synthetic route to pyrimidinyl nitronyl nitroxides, in which the bis-N-oxy fragment is incorporated in a six-membered ring. The synthesis of 2,4-diamino-2,4-dimethylpentane and 2,4-bis(hydroxylamino)-2,4-dimethylpentane, convenient precursors of these nitroxides, is described and full characterization of a series of pyrimidinyl nitronyl nitroxides is reported, along with a preliminary study of their coordination properties. 相似文献
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Finn Radner Carl Johan Hersvall André Rassat Jan -Henrik Ardenkjaer-Larsen Serge Gambarelli Daniel Jaouen 《Research on Chemical Intermediates》1996,22(5):417-425
The 2,5-di-tert-butyl-3,4-dimethoxycarbonyl-pyrryloxyl radical has the small est line-width and the smallest nitrogen hyperfine splitting reported for a stable nitroxide. The influence of long range proton splittings was shown by selective and total deuteriation. As expected on theoretical grounds, line widths and nitrogen hyperfine splitting are correlated. 相似文献
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C. -X. ZHAO Z. -B. Zhou H. -Y. He Z. -Y. Weng S. -J. Xue A. -D. Zhang 《Research on Chemical Intermediates》1995,21(1):1-6
Twenty-two polysubstituted 2-aminopyrimidines dissolved in F1 13 (CC1F2-CCl2F) solutions containing ([H(CF2CF2)nCO2]2 n = 1,2) and H(CF2CF2)nNO [? H(CF2CF2)n ? + NO] have been oxidized into detectable ω-H-perfluoroalkyl pyrimidinyl nitroxides along with neutral products. A mechanism involving Habstraction from the amino groups by H(CF2CF2)nN(O?)(CF2CF2)nH and the subsequent radical steps was suggested for the generation of the nitroxides. Some relationships between aN values and the nature of the ring substituents are discussed. 相似文献
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用四(4-吡啶基)卟啉(H~2TPyP)与乙酰丙酮钇(III)[Y(acac)~3.H~2O]反应,生成单层配合物Y(TPyP)(acac)。将其与4,5-二(庚基)二氰基苯混和,后者在DBU催化下发生四聚反应,生成混杂[2,3,9,10,16,17,23,24-八(庚基)酞菁][四(4-吡啶基)卟啉]合钇(III)二层配合物Y(TPyP)[Pc(C~7H~1~5)~8]。该化合物用紫外-可见、近红外、红外及质谱等进行了表征,并用循环伏安法(CV)和差示脉冲法(DP)研究了其电化学性质。 相似文献
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Xiao Qiu 《Journal of organometallic chemistry》2009,694(24):3958-6658
Novel ferrocenyl nitroxides 3−6 were prepared as models for studying the linkage structure-activity relationship. Single-crystal X-ray structures of compounds 4 and 5 were determined and comparatively studied. The in vitro antioxidative activities (e.g. scavenging superoxide anion and hydroxide radical) of compounds 3−6 and 4-ferrocenamido-2,2,6,6-tetramethyl-piperidin-oxy (2) were evaluated. Compounds 3 and 5 exhibit high scavenging activities in low concentration. Results from electrochemistry and UV/Vis spectroscopy show that the redox property and antioxidative activity are closely related to the structure of the linkage bridging ferrocene and cyclic nitroxide moieties. The results further indicate that the ferrocene moiety plays a principal role in antioxidation. The modification of linkage was found to be able to decrease the ferrocene/ferrocenium potential and improve the antioxidative activity effectively. 相似文献