分光光度法测定高纯度膨润土吸蓝量

以分光光度法测定高含量膨润土吸蓝量,应用正交试验设计对分光光度法的实验条件进行优化,确定的最佳实验条件:煮沸时间为5 min,4%焦磷酸钠溶液加入体积为20 mL,0.01 mol/L亚甲基蓝溶液加入体积为30mL,振荡时间为15 min。该法与滴定法对比,测定值相对误差在4%以内,相对标准偏差为1.04%,可满足高纯度膨润土吸蓝量的分析要求。     

紫外可见分光光度法快速测定苯硫酚

设计合成一种全新的苯硫酚检测探针。以试卤灵钠为主要原料,在三乙胺催化下与2,4-二硝基氯苯合成了7-(2’,4’-二硝基苯氧基)-3H-吩噁嗪-3-酮,产率为41.7%。在p H 7.4的磷酸盐缓冲溶液中,该化合物能与苯硫酚发生亲核取代反应,反应体系在可见光区λ=580 nm处有强吸收。该探针测定苯硫酚的线性范围为0.1~20μmol/L,检出限为8.9×10–8 mol/L,精密度为3.7%(n=8),回收率为106%。该方法可快速检测环境及生物体中的苯硫酚。     

荷移光度法测定注射用头孢唑啉钠含量

以注射用头孢唑啉钠作为电荷给体,百里酚蓝作为电荷受体,用分光光度法研究了它们之间形成电荷转移配合物的条件。结果表明:在乙醇介质中,二者于室温即可形成1∶1的配合物,其最大吸收波长为450nm,4.67~93.32mg·L-1范围内呈线性关系,相关系数是0.9986,稳定常数是106.34,表观摩尔吸光系数ε=3.45×104L·mol-1·cm-1。对形成配合物的机理进行了探讨。应用拟订的方法对注射用头孢唑啉钠进行了含量测定,结果与文献方法一致,平均回收率为99.9%。     

Spectrophotometric, potentiometric and chromatographic pKa values of polyphenolic acids in water and acetonitrile-water media

The pK_a values of nine polyphenolic acid substances in water and acetonitrile-water mixtures using potentiometric, spectrophotometric, and liquid chromatographic (LC) measurements, have been determined. Also, a new method based on the absorbance spectra at the maximum of chromatographic peaks previously obtained has been applied. This method can be applied to data obtained from LC-UV (diode array detection (DAD)) instruments and retains all the advantages of LC and spectrophotometric methods, such as the possibility of working with impure samples. Finally, the advantages of the different methods to the determination of pK_a values of nine polyphenolic acids have been described in order to verify the applicability of the proposed methods in aqueous and acetonitrile-water media.     

磷钒钼黄差示分光光度法测定阳图 PS 版显影液中的磷

建立了一种与高倍硅共存的磷的分析方法,共存硅对磷钒钼黄色体系的干扰程度与反应介质中硝酸浓度有关,介质中浓度为０．７４ｍｏｌ／Ｌ的硝酸可有效抑制３１倍量的共存硅的干扰。在稀硝酸中煮解,可将六偏磷酸钠转化成正磷酸。     

脑塞通中11种元素含量的测定

采用火焰原子吸收分光光度法测定了脑塞通中钠、钾、镁、钙、铁、铬、锰、镍、镉、铜、锌１１种微量、宏量元素的含量。结果表明,脑塞通中含有丰富的微量,宏观元素。为探讨中成药中微量,宏量与治疗脑血管疾病的关系提供了有用的依据。     

Kinetic Spectrophotometric Determination of Trace Aluminum by Catalytic Activity of Al<Superscript>3+</Superscript> on the Oxidation of Methylene Blue by Hydrogen Peroxide

A novel kinetic spectrophotometry for the determination of trace aluminum is described based on the catalytic activity of Al³⁺ on the redox reaction between methylene blue (MB) and hydrogen peroxide in acetate buffer (pH 3.8). The reaction is monitored spectrophotometrically by measuring the decrease in absorbance of the dye at the maximum absorption wavelength of 670nm. The variables that affected the reaction rate were fully investigated, and the optimum conditions were established. Aluminum can be determined in the range of 0–80ngmL^–1 with a detection limit of 1.0ngmL^–1. The relative standard deviation for 10 replicate determinations of 40ngmL^–1 aluminum is 0.9%. The method was used to determine aluminum in tap water and biological samples and produced satisfactory results.Received December 18, 2002; accepted May 5, 2003 published online August 22, 2003     

汽车尾气净化催化剂中钯含量的测定

贵金属钯是汽车尾气净化催化剂(以下简称汽车催化剂)的活性元素之一。为了综合平衡地利用贵金属资源以及降低催化剂成本,用钯替代铂、铑活性成分,甚至采用全钯催化剂一直是国内外汽车催化剂的研究热点[1]。钯属稀有资源必须回收利用,回收时必须对钯准确测定[2]。目前的分析方法[3-6]多集中于分析测试仪器的利用和分光光度法显色体系的研究,对于块状结构的汽车催化剂的溶样方法的研究,是选择浸出活性组分回收汽车催化剂中铂族金属元素的关键[7]。PdO难溶[8],用甲酸对催化剂中被氧化的钯进行还原预处理,利用分光光度法测定选择性浸出钯。…     

Spectrophotometric Determination of Selenium Using Potassium Iodide and Starch as Reagents

 This study describes a rapid and sensitive spectrophotometric method for the determination of trace amounts of selenium, using starch and iodine as chromogenic reagents. The proposed method is based on the reaction of selenium with potassium iodide in an acidic medium to liberate iodine. This reacts with starch to form a blue colored species with an absorption maximum of 570 nm. Beer’s Law was obeyed in the range of 2–12 μg of selenium. The molar absorptivity and Sandell’s sensitivity were found to be 1.40×10⁴ L mol⁻¹ cm⁻¹ and 5.45×10⁻³ μg cm⁻² respectively. The proposed method was successfully applied to determine selenium in a sample of natural water, polluted water, soil sludge, biological samples and human hair. Correspondence: Department of Studies in Chemistry, Managalore University, Mangalagangothri, Karnataka, India. e-mail: nbadiadka@yahoo.co.uk Received August 2, 2002; accepted October 29, 2002     

蒙药配方中常用药材的微量元素分析

本研究利用原子吸收分光光度法测定了蒙药配方中14种常用药材的铜、铁、锌、硒四种必需微量元素的含量。