注入热焓法测定萃取磷酸中三氧化硫

以钡离子与硫酸根离子沉淀反应的热效应为基础，通过测定孤立体系中的温度变化，建立了测定萃取磷酸中三氧化硫的注入热焓法，该法在４．０－３２．０ｇ／Ｌ范围内可准确测定ＳＯ３的含量，相对标准偏差为１．８％；标准加入回收率为９８％－１０３％。     

微分电位溶出法测定车间空气中镉的研究

以０．５０ｍｏｌ．Ｌ＾－１盐酸为底液，预镀汞膜的玻碳电极为工作电极，用微分电位溶出法对车间空气中镉进行测定，用标准加入法定量，在选定的条件下，线性关系良好，精密度ＣＶ为１．２５６％－２．２３％，平均回收率为９６％－１０７％，本法与原子吸收法对比，测定结果显著性差异，结果令人满意。     

固相复合抗体放射免疫分析法测定人体SOD的含量

本文描述了固相复合抗体放射免疫分析法测定人血清和红血球中超氧化物歧化酶的含量，该法灵敏度为０．５ｎｇ，非特异为２．０±０．６％，批内误差在３．４％～４．２％（ｎ＝９）之间，批间误差在７．０％～７．５％（ｎ＝６）之间，经测定，人血清正常值为２９１±７９（ｘ±ｓ）ｎｇ／ｍＬ，红血球正常值为８６１±９５（ｘ±ｓ）×１０＾－６Ｈｂ。该法灵敏度高、特异性好，简便，快速，适于分析大量样品。     

流动注射-氢化物发生-原子吸收光谱法测定雪中的微量铅

建立了测定雪中微量铅的流动注射-氢化物发生-原子吸收光谱法。在优化条件下。测定铅的线性范围为0～52．0ng／mL，线性回归方程为A=0．018c 0．016，相关系数r=0．9995，检出限为0．2ng／mL。用于雪中微量铅的测定，加标回收率为94．2％～107．3％，相对标准偏差为1．47％～3．22％。该方法的测定结果与标准加入法基本一致。     

分光光度法快速测定低合金钢中的铌

用盐酸—过氧化氢溶解试样，在2．9mol／L盐酸溶液介质中，铌与氯磺酚—S形成稳定的蓝紫色络合物，其最大吸收波长约为650nm，用分光光度法可以测定低合金钢中的铌。用该法对含铌标准样品进行测定，测得值与标准值基本一致，测定结果的相对标准偏差为2．1％～6．7％。     

微波消化技术在生物微量元素测定中的应用

用微波消化技术消化了多种食物样品．与传统的干、湿消化法相比，微波消化更加简单、快速、节省、沾污少、损失少、环境污染少．用原子吸收测定样品中的Ｆｅ，Ｃ．Ｖ＜２％，加标回收率为９８％～１００％，测定美国生物标准物质牛肝中的Ｆｅ的相对误差为０．３％，结果令人满意．     

絮凝剂中铝、砷、镉、汞、锰和铅的测定

1 引 言聚合硫酸铝是一种新型絮凝剂，可以用作污水处理。一般固铝含量为１０％～３０％，Ａｓ、Ｃｄ、Ｈｇ、Ｍｎ、Ｐｂ的含量为ｎｇ～ｍｇ／Ｌ级。通常测定这些元素的方法为分光光度法、原子吸收法、滴定法、原子荧光法等。这些方法对于聚合硫酸铝来讲，有的达不到测定灵敏度，有的基体干扰严重，有的前处理繁琐、费力，有的测定费时，并且大多数方法不能同时测定多元素。以等离子体质谱法测定絮凝剂聚合硫酸铝中的６种有毒元素Ａｌ、Ａｓ、Ｃｄ、Ｈｇ、Ｍｎ、Ｐｈ含量，测定准确度分别为9７．０％、１０４％、８８．４％、９２．８％、９…     

应用微分电位溶出法测定固体食品中的铅

以0．16moL／LHNO3为底液．预镀汞膜的玻碳电极为工作电极，用微分电位溶出法对固体食品中的铅进行测定，用标准加入法定量。检出限2．5×10－9，变异系数0．7％～5．7％，回收率93％～106％，本法与原子吸收法对比，测定结果无显著性差异．     

石墨炉原子吸收光谱法测定涂料中的铅

采用干灰法消化涂料样品，建立了测定涂料中铅含量的石墨炉原子吸收光谱法。讨论了灰化温度、原子化温度对测定铅的影响。铅的浓度在0．6～3．0μg／L范围内符合比尔定律，相关系数r=0．9996，涂料样品测定结果的RSD为1．3％，加标回收率为99．2％～102．1％。     

火焰原子吸收光谱法间接测定饲料预混硒中硒

研究了用火焰原子吸收光谱法间接测定饲料预混硒中硒，与其它方法比较，简单、快速，测定的相对标准偏差小于5．0％，回收率为96．3％-104．0％，检出限为0．0005％。     

Zwei neue basische Yttrium-Nitrate: Y(OH) x (NO3)3−x ·H2O und YO x/2(NO3)3−x (x=1.5)

Summary The intermediate precipitate, resulting by thermal decomposition and stepwise hydrolysis of yttrium-nitrate, was investigated by chemical analysis, TG, IR, and X-ray powderdiagrams and was found to be a definite hydroxynitrate Y(OH)_1.5(NO₃)_1.5·H₂O. Thermal decomposition resulted in the oxynitrate YO_0.75(NO₃)_1.5, stable from 140–280°C, which was characterized in an analogous manner.

     

不同稀土改性SO42-/ZrO2催化剂的结构与性能表征

Solid superacid catalyst SO₄^2-/ZrO₂ was modified by different rare earth compounds and applied to the esterification of acetic acid and n-butanol. The effects of rare earth elements loading on the catalytic properties were studied and the correlation between the structure and properties was investigated by means of XRD, IR, UV, DTA and TG. The results show that the (NH₄)₂Ce(NO₃)₆ modification can enhance catalytic activity more and exhibit better stability than the other two compounds La(NO₃)₃ and Ce(NO₃)₃. Meanwhile,(NH₄)₂Ce(NO₃)₆ modification can restrain the loss of SO₄^2- efficiently. The optimum calcination temperature and molar ratio of Ce(NH)∶Zr for SO₄^2-/ZrO₂ catalyst modified by (NH₄)₂Ce(NO₃)₆ are 450 ℃ and 2, respectively.     

硝酸钕和钐的水合物在水中溶解热的测定

本文用补偿式数字量热计测定了六水、四水硝酸钕和六水、五水硝酸钐298.15K时在水中的溶解热,求得了它们的标准生成热、相应的标准脱水焓和晶格能。     

On the stability of NF4NO3 and a new synthesis of fluorine nitrate

The reaction of NF₄⁺SbF₆⁻ with alkali metal nitrates in either CH₃CN or SO₂ solution at low temperatures produces FONO₂ in quantitative yield. Attempts were unsuccessful to prepare FONO from NF₄SbF₆ and KNO₂ in an analogous manner.     

Reindarstellung von Lanthan- und Praseodym-Ammoniumdoppelnitraten durch fraktionierte Kristallisation in großem Maßstab

Summary Lanthanum ammonium nitrate of purity 97%, containing 34.1 kgRE ₂O₃, was crystallized fractionally and yielded 32.5 kg oxide of purity better than 99.9% (the larger part was 99.99% pure). Out of mixtures with 66% Pr there resulted praseodymium ammonium nitrate containing 13.45 kg oxide of purity better than 99.5%. The effective separation factors are discussed, showing a better efficiency of the ammonium than of the magnesium double nitrates for the separation of praseodymium and lanthanum.

     

LiNO_3-KNO_3-H_2O三元体系相平衡研究

本文采用等温法分别测定了KNO3-H2O体系的溶解度相图以及LiNO3-KNO3-H2O体系在273.15和298.15K的等温溶解度相图。结果表明在273.15K时LiNO3-KNO3-H2O体系的溶解度等温线有2条分支,对应的固相分别为KNO3和LiNO3·3H2O,共饱点组成为31.55wt%LiNO3和7.07wt%KNO3。该体系在298.15K的等温线有3条分支,对应的固相分别为KNO3,LiNO3和LiNO3·3H2O,2个共饱点组成分别为50.42wt%LiNO3,22.18wt%KNO3,和55.74wt%LiNO3,10.9wt%KNO3。     

Cu(NO3)2(La(NO3)3)-CO(NH2)2-H2O三元体系的等温溶度研究

本文首次报道三元体系Cu(NO₃)₂-CO(NH₂)₂-H₂O(30℃)和La(NO₃)₃-CO(NH₂)₂-H₂O(25℃)的等温溶度及饱和溶液、折光率,绘制相应的溶度图及折光率-组成图。体系中发现有组成为Cu(NO₃)₂·4CO(NH相似文献   

Etude du Systeme Ternaire H2O-Al(NO3)3-Mg(NO3)2 I - Isothermes 15, 25, 30, 40 et 50°C

The solid-liquid equilibria of the ternary system H₂ O-Al(NO₃ )₃ -Mg(NO₃ )₂ were studied at 15, 25, 30, 40 and 50°C by using a synthetic method which allows to determine all the characteristic points of isothermal sections. In all isotherms the liquidus exhibit two curves corresponding to the saturation in Mg(NO₃ )₂ ⋅6H₂ O and Al(NO₃ )₃ ⋅9H₂ O. Neither double salts nor mixed crystals are observed in the temperature and composition field studied. This revised version was published online in July 2006 with corrections to the Cover Date.     

Applications of ethylammonium and propylammonium nitrate solvents in liquid-liquid extraction and chromatography

Ethyl- and propylammonium nitrate are novel ionic solvents, liquid at room temperature, suitable for use as selective solvents for the isolation of analytes containing proton donor functional groups (alcohols, amines, phenols, carboxylic acids, etc.) by liquid-liquid distribution. These solvents form immiscible solvent pairs with non-polar aliphatic and aromatic hydrocarbons, ethers and alkyl halide solvents (e.g., methylene chloride, chloroform). Analytes can be recovered from the ionic solvents by back-extraction into ah organic solvent after dilution with water or pH buffer or, preferably, by extractive derivatization when gas chromatography is used for the analyses, avoiding the accumulation of salt on the column that results in poor baseline stability. Alkylation, acylation and particularly silylation are suitable methods for extractive derivatization using standard reaction conditions. Applications are presented for the isolation of polar analytes from an urban dust, shale oil and urine samples and for the determination of low-molecular-weight alcohols in gasahol and glycerol in soap. Liquid-liquid chromatographic systems with the liquid organic salt as stationary phase can be used to predict distribution constants for a particular separation and for the separation of polar solutes, particularly isomeric compounds possessing a proton donor functional group.     

Phase Diagram of the AgNO3–CsNO3 System

The phase diagram of the binary AgNO₃–CsNO₃ system was constructed using differential thermal analysis (DTA) technique in the range 300–700 K. The apparatus is described briefly. The results exhibit a congruently melting compound CsNO₃·AgNO₃ (m.p.=453 K) characterized by two allotropic varieties and , an incongruently melting compound AgNO₃·CsNO₃ (m.p.=450 K) with three forms , and , two eutectics (16 mol% CsNO₃, 442 K and 32.5 mol% CsNO₃, 445 K) and a peritectic (38mol% CsNO₃, 450 K). The occurrence of the transitions of intermediates was confirmed by X-ray diffraction at variable temperatures. The phase diagram exhibits also two plateaus at 429 K and 435 K corresponding to the phase transitions of CsNO₃ and AgNO₃, respectively.This revised version was published online in November 2005 with corrections to the Cover Date.