Spectrophotometric Method for the Rapid Determination of Microgram Amounts of Ethionamide

Abstract

Spectrophotometric Method for the Rapid Determination of Microgram Amounts of Ethionamide

A simple and sensitive method for the determination of microgram amounts of ethionamide is described. Ethionamide is converted to corresponding 2-ethyl-γ-pyridyl thiohydroxamic acid which gives a purple violet colour (Λmax 510 nm) with ferric chloride in acidic medium. This forms the basis for the quantitative determination of ethionamide in its pure form and in tablet form. The influence of substrates, commonly employed as excipients, is studied. An attempt has been made to determine ethionamide in the presence of other antitubercular drugs.     

Sequential Spectrophotometric Determination of Microgram Amounts of Nitrate and Nitrite in Mixtures

This paper describes three new methods: the first may be used for the determination of nitrite; the second is applicable to determination of nitrate; and the third permits sequential determination of both nitrite and nitrate in mixtures with no prior separation. For the determination of nitrite and nitrate in synthetic mixtures containing 1:5 to 5:1 ratios of the ions, in tap water, and in river water, mean recoveries (for 3 to 22 μg of added NO⁻₃and NO⁻₂) are 96.1 and 98.1% (n= 15) and coefficients of variation are 2.2 and 2.5% for NO⁻₃and NO⁻₂(n= 5), respectively.     

Simultaneous Determination of Microgram Amounts of Platinum and Palladium in Presence of Base Metals by Isolation on Anion Exchange Resin-Loaded Paper and X-Ray Spectrometry

Abstract

A procedure for simultaneous determination of microgram amounts of platinum and palladium in solutions of base metals is described. The two metals are isolated on an anion exchange resin-loaded paper disk and determined by X-ray spectrometry. The method is applied to the determination of platinum and palladium in nickel matte.     

Determination of Trace Amounts of Cobalt and Copper by High Performance Liquid Chromatography with Indigo Carmine Chemiluminescence Detection

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Spectrofluorimetric Determination of Trace Amounts of Copper

A fluorescent reagent, 2,4‐dihydroxyacetophenone‐4‐hydroxybenzoylhydrazone (2,4‐DH‐AP‐4‐H‐BH) was studied on its fluorescent reaction with copper using the spectrofluorimetric method. In a water‐ethanol solution at pH 12.0, a chelating reaction occurs between copper and 2,4‐DH‐AP‐4‐H‐BH. The molar ratio of copper to the reagent is 1:2. This reaction causes characteristic changes of spectra of fluorescence with excitation and emission maxima at 342.4 and 419.2 nm, respectively. This method can quantitate the amount of copper in the reaction. It detects as little as 0.2 ppb of copper with a linear range between 0.2 to 120 ppb. It has been successfully applied to detect copper in mineral water, tea, and hair.     

Determination of Trace Amounts of Copper by Adsorptive Stripping Voltammetry

ABSTRACT

A technique is presented for the determination of trace amounts of copper(II) by adsorptive cathodic stripping voltammetry. The procedure is based on adsorptive accumulation of copper(II)-Alizarin Red S (ARS) complex on a hanging mercury drop electrode, followed by a stripping voltammetric measurement of the reduction current of the adsorbed complex at -0.16 V (vs. Ag/AgCl). The height of the copper -ARS reduction peak is linearly dependent upon the copper(II) concentration between 0.2-15 and 15-500 ng.ml^?1. The detection limit of the technique is 0.05 ng.ml^?1 copper(II) for a collection time of 1 minute. The method is free from most interferences. The procedure has been successfully applied to the determination of trace amounts of copper(II) in some analytical grade salts.     

高选择性催化法测定超痕量铜

铜是动植物必需的微量元素之一,人的血液中约含1μg·L-1,成人体内的总量约80 mg,在体内以铜蛋白的形式存在。从营养学的角度出发,对食物中的含铜量有一定要求。缺铜会导致贫血、食欲不振等症状,铜不足还影响铁的吸收。而经常食用含铜量高的食品,人体内积累过量的铜会引起中毒。我国食品卫生标准对食物中铜含量作出规定,如乳粉、甜炼乳、淡炼乳含铜量不得超过4 mg·kg-1,绿茶和红茶不得超过60 mg·kg-1,冷饮食品不得超过10 mg·kg-1(均以铜计)等[1~3]。铜的定量法很多,催化分析法是近年来新兴的一种方法,与通常的按化学计量法进行的分析方…     

催化动力学褪色光度法测定痕量铜

用催化动力学方法测定微量铜,早在20世纪初已有报道,所用的催化反应体系各不相同。也有用催化褪色反应的动力学方法测定痕量铜（Ⅱ）。本试验结果发现,在空气中,铜（Ⅱ）对钛（Ⅲ）氧化褪色反应有催化作用。     

A New Spectrophotometric Method for Determination of Microgram Amounts of Iron (II) in Pharmaceuticals

Abstract

A new spectrophotometric method was developed for the assay of 0–6 mg/1 of iron (II) in a number of certified Iraqi drugs. The Sandell index is 0.07 μg cm^2- and the ? max is 6000 1 mol^?1 cm^?1. An interference study is also described.     

离子色谱法测定气体中痕量二氧化硫

建立了测定气体中痕量二氧化硫的离子色谱法。采用氢氧化钠–过氧化氢溶液为吸收液,将气体样品中痕量二氧化硫转化为硫酸根离子,以离子色谱法测定硫酸根离子,从而得到气体中二氧化硫含量。二氧化硫气体含量在1~100μL/L范围内与色谱峰面积线性关系良好,相关系数为0.999 9。二氧化硫的检出限为0.1μg/L,测量结果的重复性小于2%(n=6),测定标准样品的回收率在98.1%~99.6%之间,准确度优于对照方法。     

反相高效液相色谱法测定新药阿司匹林铜

提出测定阿司匹林铜新药的反相高效液相色谱分析方法,采用国产ＹＷＱ Ｃ１８柱,在２５℃下,甲醇：水（含０．０８％正磷酸）：丙酮＝１１．４：８．６：１．１为流动相,苯甲酸为内标,药用标准阿司匹林和水杨酸为对照品,在ＵＶ－２３５ｎｍ下检测阿司匹林铜和杂质水杨酸铜的含量;阿司匹林铜,水杨酸铜的检出限分别为０．８７ｍｇ／Ｌ,２．４６ｍｇ／Ｌ;阿司匹林铜的回收率为９９．０％－１００．５０％;水杨酸铜的回收率为     

应用荧光纳米颗粒测定痕量铜

制备了异硫氰酸罗丹明B(TRITC)荧光纳米颗粒,于pH 6.0的磷酸盐缓冲溶液中此荧光纳米颗粒在558 nm光的激发下,于586 nm波长处发射荧光.铜(Ⅱ)的存在可使此荧光纳米颗粒溶液的荧光发生猝灭.借此,构建了一种检测微量铜的方法.在最佳试验条件下,该方法测定铜的线性范围为5.00×10-5～3.50×10-4 mol·L-1,其回归方程为F/F0=8.425 2-1.009×10-6 c,检出限为3.55×10-5 mol·L-1.     

流动注射光泽精化学发光法测定痕量铜

光泽精（Lucigenin,LC）化学发光体系是一个性能优良、应用广泛的化学发光体系,在国内对该体系的研究与应用还很少,文献[1]对LC发光体系作了较深入、系统的研究,本法在此基础上应用于水样品中痕量铜的测定,并获得了较好的效果。     

The Estimation of Total Non-Volatile Nitrosamines and Nitrosamides in Microgram Amounts

Abstract

Nitrosamines and nitrosamides are denitrosated by thionyl chloride to form nitrosyl chloride, which can be volatilized in a stream of nitrogen, trapped in alkali and determined as inorganic nitrite. Other compounds containing a N-O bond such as nitramines and nitramides do not react similarly under the conditions used.     

动力学-双波长法测定岩石矿物中痕量铼及负峰可测性研究

铼(Ⅳ)催化α-呋喃甲酰二肟(α-FDO)酸解反应,在一定条件下其光谱的正、负峰吸光度之和与时间星线性并与铼浓度相关。据此,建立了动力学一双波长测定痕量铼的方法。方法检出限为0.05ng/ml,铼浓度在<10ng/ml范围线性颇佳,表观摩尔吸光系数ε为4.5×10~7L·mol(-1)·cm~(-1)。方法用于辉钼矿和岩石中痕量铼的测定,结果与中子活化等方法相符。本文还就本体系为例对分光光度法中负峰的出现和可测规律进行了探讨。     

萃取光度法测定溴化锂中微量铜

对环境友好的高浓度溴化锂溶液由于具有强烈的吸收水蒸气的能力，可使冷剂水的蒸汽压下降，从而促使冷剂水蒸发。由于水的蒸发热较大，使冷剂水的温度迅速下降，这便是吸收式制冷机制冷的基本原理。因不存在对大气臭氧层破坏的潜在危害而被制冷行业广为推崇。     

Determination of Benzylpenicillin,Ampicillin, and Carbenicillin by Paper Chromatography

A mobile phase was developed for selective determination of benzylpenicillin, carbenicillin, and ampicillin in drugs by paper chromatography.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 4, 2005, pp. 613–615.Original Russian Text Copyright © 2005 by Alekseev, Nersesova, Khalyapina.     

2．5次微分溶出伏安法测定水中痕量铜

报告了测定痕量铜的一种新方法。在０．０１ｍｏｌ／ＬＨＡｃ－ＮａＡｃ溶液中，铜和乙醛酸缩氨基硫脲（ＧＡＴＳＣ）形成的配合物产生一很灵敏的还原峰，峰电位是－０．３３Ｖ（ｖｓ·ＳＣＥ），铜的浓度在１．０×１０－８～２．０×１０－６ｍｏｌ／Ｌ范围内成直线关系，检测限为３．０×１０－９ｍｏｌ／Ｌ，该法用于测定水中痕量铜，结果令人满意。     

壳聚糖预分离富集-离子色谱法测定痕量草酸根

本文通过壳聚糖(CTS)对水样中草酸根的预富集,利用离子色谱作为检测手段,建立了测定痕量草酸根的新方法。研究了CTS对C2O42-的吸附行为,考察了吸附时间、CTS用量、共存离子等对吸附率的影响。结果表明:在pH=3.0时,CTS对C2O42-的吸附率最大,可达100%;吸附后的C2O42-用0.1 mol/L的NaOH即可定量解吸,解吸率为96%;C2O42-的检出限为4.3μg/L,相对标准偏差(RSD)为7%(n=6)。CTS对C2O42-的等温吸附特性符合Langmuir方程,其饱和吸附量为194.0 mg/g。本方法用于水样中C2O42-的测定,结果满意。     

火焰原子吸收光谱法测定粗铜中痕量铋、锑

粗铜样品经硝酸溶解,所得样品溶液中的铜离子在过量氨水中生成可溶性铜氨络离子,而铋、锑则以氢氧化铁和氢氧化镧作载体共沉淀,实现了富集铋、锑并与铜分离。基于此提出了原子吸收光谱法同时测定粗铜中的微量铋、锑。对浓盐酸的用量,硝酸铁和硝酸镧的加入量等试验条件进行了优化。铋的质量浓度在10 mg.L-1以内、锑的质量浓度在5 mg.L-1以内分别与其吸光度呈线性关系,检出限(3s)分别为0.06,0.04 mg.L-1,相对标准偏差(n=10)均小于2.0%。