一种测定六价铬的新方法

基于六价铬在稀盐酸介质中氧化盐酸羟胺产生亚硝酸根 ,而亚硝酸根可使对硝基苯胺重氮化并与α -萘胺偶联产生红色偶氮染料 ,提出了分光光度法测定六价铬的新方法。在最佳实验条件下 ,六价铬的浓度在0～ 5 0 μg/2 5mL内服从比耳定律 ,其线性相关系数γ为 0 .9990 ,表观摩尔吸光度ε51 0 为 2 .48× 1 0 4 L·mol- 1 ·cm- 1 。所拟方法用于水样中微量铬的测定 ,结果满意     

高浓度臭氧化学分析法

根据文献[1]用KI溶液吸收O_3,然后滴定溶液中产生的I_2。在建立方法过程中,我们发现按文献[1]的条件操作时,对同一样品,分析结果差别很大。当O_3被0.5mol/L浓度的碘化     

测定可逆反应动力学参数的一种新方法

提出了测定一级可逆反应速率常数的新方法,用以测定稀土的偶氮胂Ⅲ络合物与CyDTA交换反应的速率常数,并详细讨论了测定速率常数时动力学数据的选取原则。     

计算9.6微米臭氧带冷却率的一种新方法

本文用一种新的计算方法,计算了9.6微米O_3带的冷却率.经过与逐线积分结果的比较,证明了这种新的算法可以精确处理目前红外辐射传输计算中尚未获得圆满解决的频率积分、角度积分以及非均匀路径等问题.新算法在计算时间方面也是比较节省的.同时,文中还表明了通常的带模式方法中所使用的CG近似、漫射因子近似等,对9.6微米O_3带基本上是不适用的。     

一种测定赤砂糖中二氧化硫的新方法

食品中二氧化硫的含量测定 ,采用的是国家标准ＧＢ5 0 0 9.34 96盐酸副玫瑰苯胺法[1 ] ,但该法在实际运用中却存在着许多不足之处 ,如ＳＯ2 的吸收剂采用的是剧毒四氯汞钠试剂 ,且该试剂配制好后需放置过夜后过滤才可使用 ;而显色剂盐酸副玫瑰苯胺溶液的配制也较为麻烦 ,需时较长 ;更为严重的是 ,该法在未扣除有色试样背景干扰的情况下 ,对有色试样采取直接取样进行分析 ,这就给测定结果带来了较大的误差 ,特别是测定诸如赤砂糖这类颜色较深的物质中ＳＯ2 含量时 ,其较深的背景严重干扰测定 ,且测定结果往往还因其取样量的不同而不同 ,这就…     

一种快速测定铅离子的新方法

利用分光光度计扫描加入铅离子前、后胶体金/DNA体系光谱,通过比较加入铅离子前、后A660/A530大小来快速定量铅离子。加入铅离子后,体系A660/A530变化较其他离子的大,颜色由红色变成蓝色,建立了简单、快速检测铅离子的胶体金/DNA体系新方法。该方法的线性范围为0.05～2.5μg/mL,检出限为0.02μg/mL,线性相关系数r=0.999。     

餐饮业污水中动植物油测定的一种新方法

红外分光光度法是我国目前测定油类的标准方法,也是一种在对油含量测定中既能进行定性分析,又可以进行定量分析的方法.但是该方法最高检出浓度低,对含油量较高的餐饮业废水需要稀释后才能进行测定,此操作过程较繁琐,且大量消耗四氯化碳,对环境和人体均有不良影响.本研究在红外分光光度法的基础上,提出了一种简便、快捷、高检出浓度的餐饮...     

一种测定食品中微量铁的新方法

提出了一种用分光光度法测定食品中微量铁的新方法，即在微酸性条件下，铁与邻硝基苯基荧光酮、表面活性剂ＣＰＣ形成蓝色的三元络合物。该法简便、体系稳定、灵敏度高，用于测定茶叶、大豆中的微量铁，取得满意结果。     

一种测定氯化铵中钾和钠离子的新方法

在有色冶金、电池等行业的技术难题都与其使用的原料——工业级氯化铵中钾钠离子和其它的碱金属、碱土金属离子的含量过高有关。如用工业级氯化铵生产仲钨酸铵时,只能生产1级、2级的粗放型产品,而难以生产国际上十分抢手的零级产品。如果能将工业级氯化铵中的碱金属含量降到xxμg·g-1,则为生产出零级仲钨酸铵创造了有利条件。眺山化工厂的主要产品为碳酸钾,其副产品为     

Ion-Chromatographic Determination of Low Concentrations of Nitrate in Solutions of High Salinity

The determination of low concentrations of inorganic anions in water samples of high salinity is one of the most difficult tasks in analytical chemistry. There is, however, an increasing demand for the exact and reliable determination of nutrients even at very low concentration levels in environmental samples of complex composition. We therefore present the development, quality control and application of an easy and rugged method that makes possible the determination of trace amounts of nitrate in solutions with high concentrations of chloride (>30 000 mg L⁻¹) and a hundred-fold excess of bromide ions, based on ion chromatography with UV detection at λ = 210 nm. While chloride ions show no absorbance at this wavelength, a bromide concentration >1500 μg L⁻¹ severely interferes with nitrate determination at the trace level. On the contrary, at nitrate concentrations of >500 μg L⁻¹, this bromide interference becomes negligible. Consequently, to overcome the impact of bromide on the trace level determination of nitrate, all samples are spiked with a definite volume of a nitrate standard solution to obtain an overall nitrate concentration of >500 μg L⁻¹ which allows the exact and reliable determination of nitrate concentrations down to 25 μg L⁻¹. We will report the successful application of the method to samples of high salinity.     

A New Indirect Electrochemical Method for Determination of Ozone in Water Using Multiwalled Carbon Nanotubes

A new electrochemical methodology has been developed for the detection of ozone using multiwalled carbon nanotubes (MWCNT). The method presented here is based on the reaction of ozone with indigo blue dye producing anthranilic acid (ATN). The electrochemical profile of ATN on an electrode of glassy carbon (GC) modified with MWCNT showed an oxidation peak potential at 750 mV vs. Ag/AgCl. An analytical method was developed using differential pulse voltammetry (DPV) to determine ATN in a range of 50–400 nmol L^?1, with a detection limit of 9.7 nmol L^?1. Ozonated water samples were successfully analyzed by GC/MWCNT electrode and the recovery procedure yielded values between of 96.5 and 102.3 %.     

分光光度法测定高纯氧化铝中的二氧化硅

在含有明胶聚乙烯醇 (PVA)和草酸的 0 .0 1 2～ 0 .0 60 mol/L 盐酸介质中 ,罗丹明 B(RB)与硅钼杂多酸能形成离子缔合物 ,发生高灵敏显色反应 ,缔合物在 585nm处的表观摩尔吸光系数ε=1 .8× 1 0 5L· mol-1· cm-1,缔合物可稳定 2 4 h以上 ,此法已用于测定高纯氧化铝中的二氧化硅     

Semiconductor Sensors for Studying the Heterogeneous Destruction of Ozone at Low Concentrations

Prospects for the use of semiconductor resistive sensors in studies of the heterogeneous destruction of ozone at low concentrations (5–400 μg/m³) were shown. The influence of various factors (sensor temperature, gas flow rate, ozone concentration) on the results of ozone concentration measurements with sensors of various types was studied. Methods for forming a sensitive layer of In₂O₃(3% Fe₂O₃) sensors with specified parameters of calibration curves were proposed. The optimum conditions for the operation of sensors in a flow mode were formulated. The results of the study of heterogeneous destruction of ozone on microfiber polymer and natural disperse (sand, coals) materials obtained by the developed method were presented.     

火焰原子吸收光谱法测定高纯碳酸锂中多种杂质元素

采用火焰原子吸收光谱法测定了高纯碳酸锂中多种杂质元素（包括锌、钠、铅、钾、铁、钙及镁）的含量。结果表明：测定上述各元素的相对标准偏差（n=9）在1.9%～4.4%之间。各元素的工作曲线具有良好的线性关系,相关系数在0.9943至0.9998之间。用标准加入法做回收试验,测得平均回收率在98.3%至101.0%之间。     

高效液相色谱法测定西红柿中克线磷残留量

高效液相色谱法测定西红柿中克线磷残留量包宏,夏民洲,胡兹苓（南京林业大学南京２１００３７）１前言克线磷（ｆｅｎａｍｉｐｈｏｓ）,商品名Ｎｅｍａｃｕｒ,是防治作物根结、孢囊与自由线虫的杀线虫农药￣［１］。对它的残留分析,有气相色谱法和薄层色谱法等￣［２...     

高效液相色谱法测定阿卡波糖水解产物中的Valienamine含量

1引言Valienam ine((1S,2S,3S,4R)-1-氨基-5-(羟甲基)环己-5-烯-2,3,4-三元醇),分子式C7H13NO4,是一种由假单孢菌降解井冈霉素获得的假氨基糖,可通过阿卡波糖或井冈霉素水解来制备。它不仅能够有效治疗糖尿病及高血糖所导致的肥胖症,而且还能治疗艾滋病等其它疾病,所以对其的研究和开发已引起全世界生物医学领域的广泛关注。Valienam ine的检测方法主要有糖化酶检测法、紫外分光光度法、质谱法和薄层扫描法等,这些方法都存在难于定量或定量不准确、检测不方便的缺陷。有人用p-硝基氟苯与Valienam ine反应衍生生成N-p-硝基苯-Valienam …     

血清中阿斯匹林和水杨酸浓度的快速高效液相色谱法测定

A fast method for determining concentrations of aspirin and salicylic acid in serum using reversedphase high performance liquid chromatography with Spherisorb C18 column,MeOH i H2O: n-BuOH : H3PO4 (300:200 :10 :0. 5,volume ratio) eluent and UV-237 detector was eatablished. The linear range of the method is 1-20μg/mL (r=0. 9996)for aspirin and 2 30μg/mL (r=0. 9981) for salicylic acid. The averagerecoveries are 96. 0 %-106. 0% and 92. 0%-119.5% ,respectively.     

Determination of Radical Concentrations in Copolymerization

The determination of the individual conversion rate of each monomer in a radical copolymerization allows the absolute concentration of each kind of growing radical to be derived, provided the reactivity ratios and the homopropagation rate constants are known. The procedure is applied to the following binary copolymerizations: styrene-methyl methacrylate, vinyl chloride-vinyl acetate, acrylonitrile-vinyl acetate, and acrylonitrile-vinyl chloride. In the two latter cases, the anomalous behavior, probably caused by the internal cyclization reaction involving CN bonds, is well evidenced.     

A High Performance Liquid Chromatography Method for the Determination of Ranitidine in Plasma

Abstract

Ranitidine hydrochloride is a highly potent H₂ receptor antagonist of value in the treatment of peptic ulceration. A method is described for the determination of ranitidine in biological fluids. The drug is extracted from plasma prior to determination by reverse phase high performance liquid chromatography. The method is sensitive enough to determine 10ng ranitidine per ml in plasma. The h.p.l.c. method has been automated so that analysis can be carried out without attention over a 24 hour period. The automated h.p.l.c. method has been used for studying the pharmacokinetics of oral and intravenous doses of ranitidine hydrochloride administered to man.