Spectrophotometric determination of chromium (VI) with Methylene Blue

The interaction of Cr(VI) and the thiazine dye Methylene Blue has been examined. The ion-associate formed is extractable into 1,2-dichlorethane. The optimum conditions have been established, and values obtained for the conditional extraction constant K'(ex), distribution constant K'(D) and association constant beta'. A sensitive and selective method for determination of microquantities of Cr(VI) in soils and alloys is suggested.     

亚甲基蓝光度法测定西地那非的含量

在pH3.0～6.0的条件下,亚甲基蓝(MB)与西地那非(SD)反应,生成蓝色离子缔合物,最大吸收波长位于600nm,SD浓度在0～1.6×10-5mol/L范围服从比耳定律,由此建立了测定西地那非含量的分光光度法。缔合物的表观摩尔吸光系数(ε)为3.0×104L·mol-1·cm-1。该方法用于市售药物中西地那非含量的测定,结果满意。     

Extraction Spectrophotometric Determination of Trace Chlorine Dioxide with Methylene Blue

Abstract

The coloration reagent - leucomethylene blue, the reduction product of methylene blue, is used to determine the concentration of chlorine dioxide in the presence of Cl₂ and anion species such as OCl^?, ClO₂ ^? and ClO₃ ^?. This simple spectrophotometric method is performed by using the extractant 1,2-dichloroethane at pH 1.3. The linear range of ClO₂ measurement extends to 0.95 mgl^?1 with a detection limit of 0.02 mgl^?1. The presence of chlorine and hypochlorite ion can be masked by oxalic acid. The permissible maximum concentration of ClO₂ ^? is 2.0 mgl^?1, and ClO₃ ^? anion does not interfere with the measurement.     

亚甲基蓝褪色分光光度法测定藻酸双酯钠

在pH为2.3的盐酸介质中,藻酸双酯钠与亚甲基蓝反应形成离子缔合物,使亚甲基蓝溶液褪色,最大褪色波长位于665nm。藻酸双酯钠的浓度在2~8mg/L范围内遵守郎伯-比尔定律,测定藻酸双酯钠的百分之一吸光系数ε0.01为6.39×102。该褪色体系操作简便,有较好的稳定性、选择性与准确度。据此直接测定了片剂中藻酸双酯钠的含量取得满意结果。     

分光光度法测定脱氧核糖核酸——基于其与亚甲蓝的反应

试验发现在pH 6.5的B-R缓冲溶液中在加脱氧核糖核酸(DNA)后亚甲蓝溶液在其吸收峰666 nm波长处的吸收明显减弱(即色泽减褪),而且吸光度的减弱(ΔA)程度与DNA的质量浓度在10.0 mg.L-1以内保持线性关系,其相关系数为0.9998,此反应对DNA的检出限为0.10 mg.L-1,分别以蛋白酶、胰蛋白酶及溶菌酶作为基体定量加入DNA配制成3种合成样品,按所提出方法进行分析,测得回收率结果在98.4%~101.0%之间,分析结果的RSD(n=11)值在1.1%~3.1%之间。对反应条件(包括亚甲蓝的浓度、反应的温度、酸度及时间等因素)作了试验和选定,还对反应机理作了简要的讨论。     

Spectrophotometric and derivative spectrophotometric determination of aluminium with Hydroxynaphthol Blue

The reaction of aluminium(III) with Hydroxynaphtol Blue (HNB) in aqueous media at apparent pH 5.5 results in a red complex that is stable for at least 4 hr. Beer's Law is obeyed up to 1.6 microg/ml of aluminium(III) with an apparent molar absorptivity of 1.66 x 10(4) l.mol(-1). cm(-1) at 569 nm. This paper proposes procedures for aluminium(III) determination by ordinary and first-derivative spectrophotometry. The results demonstrated that the linear dynamic range is 0.03-1.60 microg/ml for ordinary spectrophotometry and 11.8-320.0 ng/ml for first derivative spectrophotometry. The HNB is not selectivity for aluminium, but the addition of EDTA allows the aluminium determination in the presence of accepted amounts of Ca(II), Mg(II), Mn(II), Ba(II), Sr(II), Cd(II), Pb(II), La(III), In(III), Bi(III) and Zn(II). The interference of Cu(II) and Hg(II) can be masked by thiosulphate. Ions such as UO(2)(II), Mo(VI), Co(II), Ti(IV) and PO(4)(III) do interfere seriously. This method was applied for aluminium determination in copper-base alloy, zinc-base alloy, magnesium-base alloy, iron ore, manganese ore, cement, dolomite, feldspar and limestone. The results indicated high accuracy and precision.     

Spectrophotometric determination of hydrogen peroxide with leuco Patent Blue Violet

Hydrogen peroxide (1 × 10^?7?10^?5 mol dm^?3) was determined in aqueous solution using leuco Patent Blue Violet and peroxidase. The reagent can also be applied in the same concentration range to the ethyl acetate extraction method described previously. This allows hydrogen peroxide to be determined in the presence of a variety of species which interfere in the direct method. A reagent consisting of leuco Patent Blue Violet, peroxidase, glucose oxidase and mutarotase was also applied to the determination of glucose.     

分光光度法测定亚甲基蓝溶液浓度线上实验设计

基于朗伯-比尔定律与互补色原理,利用QQ截图读取色块RGB三原色组成的功能,获得不同亚甲基蓝浓度色阶对应的红色和绿色信号,设计了亚甲基蓝测定的简易紫外-可见分光光度法实验方案。该方案包括标准色阶制作、颜色信号读取、标准曲线绘制,以及待测样品测试等。通过学生实验,获得了满意的可靠性。该实验方案尤其适用于线上教学或缺少分光光度计的线下教学。     

亚甲基蓝分光光度法测定锑浸出液中硫化钠

湿法炼锑中常采用硫化钠作为从锑矿中提取锑硫化物的浸出剂。准确测定锑浸出液中的硫化钠浓度对掌握和完善湿法炼锑工艺、提高生产效率有重要作用。将亚甲基蓝分光光度法用于锑浸出液中硫化钠的测定,考察了波长选择、体系酸度、显色时间、基质干扰等条件,测评、优化了方法;将方法应用于锑浸出液中硫化钠的测定,方法检出限为0.002mg/L,测定结果相对标准偏差≤3%,加标回收率≥90%。方法能较理想地应用于锑浸出液中硫化钠的测定,丰富了锑浸出液中硫化钠的测定方法,也为相关研究提供了支持与参考。     

亚甲基蓝分光光度法测定锑浸出液中硫化钠

湿法炼锑中常采用硫化钠作为从锑矿中提取锑硫化物的浸出剂。准确测定锑浸出液中的硫化钠浓度对掌握和完善湿法炼锑工艺、提高生产效率有重要作用。将亚甲基蓝分光光度法用于锑浸出液中硫化钠的测定,考察了波长选择、体系酸度、显色时间、基质干扰等条件,测评、优化了方法;将方法应用于锑浸出液中硫化钠的测定,方法检出限为0.002mg/L,测定结果相对标准偏差≤3%,加标回收率≥90%。方法能较理想地应用于锑浸出液中硫化钠的测定,丰富了锑浸出液中硫化钠的测定方法,也为相关研究提供了支持与参考。     

Spectrophotometric determination of epinephrine and norepinephrine with sodium periodate

A simple and accurate spectrophotometric method is described for the determination of epinephrine (EP), norepinephrine (NE) and their bitartrate salts. The method is based on the development of a red colour (lambda(max) 490 nm) with sodium periodate in aqueous alcoholic medium. The colour is stable for at least 1 hr. The molar reacting ratio of EP or NE to periodate is 1:2. The proposed method is particularly suitable for routine analysis of EP and NE injections. The interference due to the sodium metabisulphite normally used as antioxidant can be overcome by addition of acetone. Results for analysis of bulk drugs and injections agree well with those of official methods.     

Spectrophotometric determination of mercury(II) with sodium sulfite

A photometric procedure is developed for determining mercury(II) in aqueous media. It is based on the reaction of mercury(II) with sodium sulfite giving a product with an absorption maximum at 230 nm. The optimum conditions are found. The procedure allowed 0.5 to 13.0 μg/mL of mercury(II) to be determined for 1 min. The effect of some metal cations is estimated.     

阻抑次甲基蓝褪色反应动力学法测定痕量钒

在硫酸介质中,基于钒对次甲基蓝与溴酸钾和抗坏血酸的催化氧化还原反应的抑制作用,建立了高灵敏度测定痕量钒新的动力学分析方法。其检出限为3．5×10－11g／mL,线性范围0～10μg／L。方法可用于食物、药材及水中钒的测定,结果均较为满意。     

亚甲蓝与十二烷基硫酸钠变色反应光谱机理

为从分子水平认识亚甲蓝(MB)分子与大分子之间相互作用机理,应用吸收光谱法研究了MB与十二烷基硫酸钠(SDS)之间相互作用机理,考察了乙醇、氯化钠、羟丙基-β-环糊精以及Triton X-100对相互作用的影响。结果表明:MB与SDS之间能发生相互作用形成复合物产生变色反应,乙醇等对相互作用都有影响。认为MB与SDS变色反应机理是在MB与SDS大分子间发生静电相互作用基础上,结合在SDS有序集合体上MB分子定向聚集所引起的。     

The Interaction of Methylene Blue with DNA

The binding of small molecules to DNA is useful in clarifying the protein-nucleic acid interaction, drug-DNA interaction, structure and function of nucleic acids, and in rational drug design. Methylene blue (MB) is one of a number of tricyclic heteroaromatic compounds that are known to interact with DNA.