溴酸钾-亚甲蓝催化光度法测定硝酸盐和亚硝酸盐

用镉柱将NO-3 还原为NO-2 ,利用在磷酸介质中NO-2 对溴酸钾氧化亚甲蓝这一褪色反应具有强烈的催化作用而建立了同时测定痕量硝酸盐和亚硝酸盐的新方法。本方法简便、快速、灵敏 ,对亚硝酸盐和硝酸盐测定的线性范围分别为 0～ 2 0 0 μg·L-1和 0 0 0 3～ 310 μg·L-1,用于测定各种水样中痕量NO-2 和NO-3 的含量均获得满意结果     

落葵中硝酸盐、维生素C及胡萝卜素含量的研究

对野生落葵不同生长发育阶段所含的硝酸盐、维生素C及胡萝卜素进行了测定和分析,并将野生落葵和人工栽培落葵所含的以上成分进行了比较.结果表明,落葵富含胡萝卜素,维生素C含量中等,野生落葵硝酸盐含量较低,人工栽培落葵硝酸盐含量比野生落葵高出近1倍,须经煮熟后方可安全食用.     

硝酸镁对GFAAS法测定微量铍的基体改进效应

以硝酸镁作为GFAAS法测量微量铍的基体改进剂,研究了硝酸镁对石墨炉灰化和原子化的影响,探讨了硝酸镁的作用机理.结果表明,硝酸镁能提高灰化温度,降低原子化活化能,并对吸收信号有延迟作用,从而有利于消除基体干扰,提高分析灵敏度.     

Manifestation of diamagnetic chemical shifts of proton NMR signals by an anisotropic shielding effect of nitrate anions

A remarkable upfield shift of the py_α protons of complexed 2,2′-bipyridine in [cis-Pd(bpy)(NO₃)₂] is observed which is considered to originate from the anisotropic influence of suitably positioned coordinated nitrate anions around the Pd(II) centre of the molecule. A typical complexation-induced downfield shift is observed for the NH₂ protons in [cis-Pd(en)(NO₃)₂] where ‘en’ stands for ethylenediamine.     

硝酸根离子介质中偏钛酸钡的水热合成

以硝酸和钛酸四丁酯为原料，在２４０℃的碱液中成功地制备了四方相ＢａＴｉＯ３运用ＸＲＤ、ＤＳＣ和ＩＲ等技术碱度、硝酸根离子、钛源活性、填充度等因素对ＢａＴｉＯ３形成、粒度和物相的作用，ＫＯＨ最适宜浓度为１．０ｍｏｌ／Ｌ，碱液中ＢａＴｉＯ３是ＢａＯ－ＴｉＯ２体系中最稳定的物相，硝酸根离子参与了ＢａＴｉＯ３晶体的成核和生长，钛源的高活性和高填充度有利于四方ＢａＴｉＯ３的形成。     

Ternäre Lithium-Selten-Erd-Nitrate mit einsamen Nitrationen: Li3[M(NO3)5](NO3) (M = Gd?Lu,Y). Die Kristallstruktur von Li3Er(NO3)6

Ternary Lithium Rare Earth Nitrates with Lonesome Nitrate Ions: Li₃[M(NO₃)₅](NO₃) (M = Gd? Lu, Y). The Crystal Structure of Li₃Er(NO₃)₆ Single crystals of the ternary nitrate Li₃Er(NO₃)₆ are obtained from a solution of “Er(NO₃)₃” in the melt of LiNO₃. In Li₃Er(NO₃)₆ (monoclinic, P2₁/n, Z = 4; a = 776.0(1); b = 748.86(8); c = 2 396(1) pm; β = 90.76(3)°; R1 = 0.0490; wR2 = 0.0792), Er³⁺ is surrounded by five bidentate nitrate ligands yielding the anionic units [Er(NO₃)₅]^2?. These are arranged in the direction of the 2₁ screw axis. Two lonesome NO₃^? ions are in the middle of such a “helix” and are connected by Li⁺ with the anions [Er(NO₃)₅]^2?. The helices are moved against each other by about half of the lattice constant a and are connected by further Li⁺ ions.     

Comparison of the Temperature Effect on the π∗←n and π∗←π Electronic Transition Bands of NO<Subscript>3</Subscript><Superscript>−</Superscript>(aq)

The effect of temperature on the π∗←π transition band in the UV absorption spectrum of NO₃⁻(aq) centered at ≈200 nm was studied in the temperature range 10–70 ^∘C. The observed temperature independence of this band was in contrast to the significant influence of temperature on the nitrate π∗←n transition reported recently by us. However, taking into account the electronic states involved in both the transitions, it was concluded that this finding was in accordance with our previous assumption that interconversion between spectrally distinct (with respect to π∗←n band) nitrate species included the rupture/formation of hydrogen bond(s) in the hydration shell of the nitrate ion.     

An In Situ Copper Plated Boron‐Doped Diamond Microelectrode Array for the Sensitive Electrochemical Detection of Nitrate

The first example of using a copper microelectrode array for use in electroanalysis is explored and exemplified with the electroanalytical quantification of nitrate. The analytical approach is based upon the in situ deposition of copper at a boron‐doped diamond (BDD) microelectrode array. The immobilized copper layer is electrocatalytic for nitrate reduction and exhibits an analytically useful range from 1.2 to 124 μM with a marked selectivity for nitrate ion over nitrate, with a limit of detection of 0.76 μM. The analytical applicability was examined through standard addition determinations of nitrate in drinking and river water samples.     

Amperometric detection of nitrite and nitrate at tetraruthenated porphyrin-modified electrodes in a continuous-flow assembly

The modification of a glassy carbon surface by coating with an electrostatically assembled film of tetraruthenated cobalt porphyrin/(meso-tetra(4-sulphonatephenyl)porphyrinate zinc(II) yields an indicator electrode that allows the determination of nitrite to be performed with a limit of detection of 0.1 μM in a flow injection configuration. The dynamic range extends up to 1000 μM and the repeatability of the measurements was evaluated to be 1.5% with a throughput of 50 samples per hour. The efficiency of the bilayered film to mediate the electron transfer allows the determinations to be performed at a less positive potential (+0.75 V) with enhanced sensitivity. The coating also prevents the surface poisoning and its stability is maintained over several weeks. The same detector was used for determination of nitrate after reduction to nitrite in a reductor column containing copperised cadmium. This method was used for the determination of nitrate and nitrite in mineral water, saliva and cured meats, the results being in agreement with certified values and those obtained by using recommended procedures.     

纸张上光油关键物质的成分分析

利用色相色谱／质谱联用技术，傅立叶红外及裂解－气相色谱／质谱联用技术，对印刷用上光油的关键成分进行了分析，共鉴定出７种挥发性组分，２种高分子聚合物。