铅锡合金中铅的示波滴定——钼酸铵释放法

本文利用Ｚｎ＾２＋在示波图上有敏锐的切口变化并可指示示波滴定终点的性质，报告了用钼酸铵释放法示波滴定铅锡合金中铅含量的新方法。本方法不用外加指示剂，共存组分不干扰测定，本文进行了多种样品中铅含量的测定，结果令人满意。     

Spectrophotometry Determination of Amitriptyline-HCl in Pure and Pharmaceutical Preparations.

ABSTRACT

Amitriptyline-HCl reacts with ammonium molybdate in concentrated sulphuric acid after heating for 20 min. at 100°C to give a green colour having maximum absorbance at 660 nm. The reaction is selective for amitriptyline with 0.01 mg/10ml as visual limit of identification and provides a basis for a new spectrophotometric determination. The reaction obeys Beer's law from 0.01 mg to 1.4 mg/10ml of amitriptyline-HCl and the relative standard deviation is 0.35%. The quantitative assessment of tolerable amount of other drags is also studied.     

Spectrophotometric Determination of Tetracyclines in Pure Form and in Pharmaceutical Preparations,by a Molybdenum Blue Method

Abstract

A new and sensitive spectrophotometric method has been developed for the determination of tetracyclines either in a pure form or in Pharmaceuticals, by a molybdenum blue method. The procedure is based on the observation that, in sulphuric acid medium, tetracyclines reduce ammonium molybdate to molybdenum blue, the absorbance of which is proportional to the amount of antibiotic present. The variables affecting development of the color have been investigated and the conditions optimized. Beer's law is obeyed for up to 20 μg/ml of tetracycline HCl and oxytetracycline HCl, 28 μg/ml of demeclocycline HCl, 18 μg/ml of chlortetracycline HCl, 32 μg/ml of doxycycline HCl and 40 μ/ml of rolitetracycline. Molar absorptivities (1 mol^?1 cm^?1) and Sandell's sensitivities (μ cm^?2 per 0.001 absorbance unit) are, respectively: tetracycline HCl 4.9×10⁴ and 0.0098, oxytetracycline HCl 5.4×10⁴ and 0.0092, demeclocycline HCl 1.6×10⁴ and 0.0313, chlortetracycline HCl 5.5×10⁴ and 0.0094, doxycycline HCl 3.4×10⁴ and 0.0141, rolitetracycline 2.7×10⁴ and 0.0195.     

An Improved Spectrophotometric Method for Determination of Penicillins Alone and in Pharmaceutical Dosage Forms

Abstract

A new spectrophotometric method for determining penicillins has been developed. A known volume of the penicillin solution is heated at 95[ddot]C for 70 min with ammonium molybdate, in sulphuric acid medium and the absorbance of the blue species formed is measured at 670 nm. The method has been successfully applied for the determination of thirteen commercially available penicillins. Beer's law is valid for up to 35-90 μg/ml of antibiotic (according to the penicillin). The procedure has been used for analysing some pharmaceutical preparations for these drugs, e.g., injections and capsules. The sensitivity of the method is largely increased with respect to the vanadate method previously described.     

聚苯乙烯磺酸钠/L-谷氨酸协同作用下碳酸钙微球的设计与合成

通过CO₂缓慢扩散,在聚苯乙烯磺酸钠(PSSS)/L-谷氨酸(L-Glu)二元体系中,与富集在有机/无机界面钙离子相结合,合成碳酸钙微球。本文系统地研究了室温下各种因素对碳酸钙晶体形貌和晶型的影响。实验表明,pH值、表面活性剂和PSSS/L-Glu的浓度比起着重要作用。通过改变实验条件,除了得到主要的球形晶体外,我们还得到了矩形、立方体形和饼形等。取向聚积机理解释了微球的形成,PSSS和L-Glu间的协同作用在晶体化过程中起着重     

分光光度法测定铁合金中的磷

以含磷较低的铁合金作底液,以钼酸铵为显色剂,用磷钼蓝光度法测定铁合金中的磷。磷钼蓝的摩尔吸光系数为7.8×10~5L/(mol·cm),与磷钼黄光度法、氟化钠-氯化亚锡还原磷钼蓝光度法相比,测定灵敏度有不同程度的提高。该方法用于实际样品分析,结果准确、可靠。     

离子色谱法测定葡萄糖酸钙中的草酸根

利用单柱离子色谱系统,以NaHCO3-Na2CO3溶液为流动相,对葡萄糖酸钙中的草酸根进行分离,并用电导检测法测定了葡萄糖酸钙中草酸根的含量。线性回归方程为y=1.147x 1.568,相关系数r=0.984,线性范围为0.01-30.00mg/L,以3倍信噪比计算,草酸根的检出限为13．2μg/L,回收率为96％－105％。     

钙作为合金元素对铝在碱溶液中的缓蚀作用及其与酒石酸盐的协同效应

通过集气法、极化曲线和电化学阻抗谱研究了在铝中添加合金元素钙对其在碱 溶液中的缓蚀作用及其与酒石酸盐的协同效应。实验结果表明,铝电极的腐蚀速率 随钙含量的增加而减小。溶液中不含酒石酸盐时,钙对电极反应的阴极过程有显著 的抑制作用,对阳极过程作用不明显;而当溶液中含有酒石酸盐时,阴极过程和阳 极过程均被显著抑制。阻抗谱的解析结果还表明,钙离子或酒石酸钙络离子是通过 减小反应物在活性位上的反应速率而起缓蚀作用的,它们可能属于界面型缓蚀剂而 非成相型缓蚀剂。     

钼酸铋光催化剂的结构缺陷调控

钼酸铋(Bi₂MoO₆)作为一种新型层状光催化材料,具有成本低廉、清洁高效、带隙较窄和可见光响应等优点,在降解水体污染物、净化空气、抑菌、光解水、二氧化碳还原及固氮等领域具有广泛的应用前景,是一种极具发展潜力的Bi(Ⅲ)基半导体光催化剂。然而该材料在实际应用中还存在太阳光吸收效率较低、光生载流子复合速率较快等亟待解决的瓶颈问题。针对上述科学问题,对Bi₂MoO₆光催化剂进行结构缺陷调控已证明是行之有效的解决策略,本文系统阐述了近年来Bi₂MoO₆晶体结构缺陷工程的研究进展,主要包括各类元素掺杂、氧空位引入以及二者的伴生协同作用等,分别从制备方法和催化性能改善等角度对Bi₂MoO₆的缺陷研究和发展动态进行了归纳,并对其在相关应用领域的构-效关系及作用机制进行了深入探讨和总结。最后,分析了缺陷型Bi₂MoO₆光催化剂目前所存在的不足,并对未来的发展方向和前景进行了展望。     

微量元素钼的测定和钼酸锂的缓蚀研究

用ＥＤＴＡ滴定法测定了钼酸盐中的钼含量，用重量法研究了钼酸锂对炭钢的缓蚀能力，结果表明，当ＰＨ４时，０．０２－０．０７％钼酸锂对Ａ３钢片的缓蚀力为３６－７４．８％。     

Corrosion Inhibition of a Green Scale Inhibitor Polyepoxysuccinic Acid

The corrosion inhibition of a green scale inhibitor, polyepoxysuccinic acid (PESA) was studied based on dynamic tests. It is found that when PESA is used alone, it had good corrosion inhibition. So, PESA should be included in the category of corrosion inhibitors. It is not only a kind of green scale inhibitor, but also a green corrosion inhibitor. The synergistic effect betweenPESA and Zn2 or sodium gluconate is poor. However, the synergistic effect among PESA, Zn2 and sodium gluconate is excellent, and the corrosion inhibition efficiency for carbon steel is higher than 99%. Further study of corrosion inhibition mechanism reveals that corrosion inhibition of PESA is not affected by carboxyl group, but by the oxygen atom inserted. The existence of oxygen atom in PESA molecular structure makes it easy to form stable chelate with pentacyclic     

鸡蛋壳制备葡萄糖酸钙的研究

葡萄糖酸钙是一种溶解度高,生理宽容性大的钙营养剂和抗过敏药,广泛用作食品添加剂及医药制剂供口服或静脉注射.目前常用的生产方法主要是生物发酵法,其缺点是工艺复杂, 生产周期长且易造成污染.本研究以葡萄糖酸δ内酯作为葡萄糖酸的来源,利用蛋壳中所含高达93%的CaCO3[1]进行中和反应制备葡萄糖酸钙,探索了一条变废为宝,工艺简单,成本低,污染小的葡萄糖酸钙生产路线.     

旋光法测定胃肠透析盐中甘露醇的含量

本文根据甘露醇与钼酸铵的络合物具有旋光性这一特点，用旋光法测定胃肠透析盐中甘露醇的含量。结果表明甘露醇浓度在０．４－１．６ｇ／１００ｍＬ范围内与旋光度呈良好的线性关系（ｒ－０．９９９３），回收率为１００．７４％（ｎ＝５，ＲＳＤ＝０．４５％）。方法较为简便，快速，准确。     

Investigation on the Adsorption and Corrosion Inhibition Behavior of Gum Acacia and Synergistic Surfactants Additives on Mild Steel in 0.1 M H2SO4

Adsorption and corrosion inhibition effect of gum acacia alone and in presence of surfactants sodium dodecyl benzene sulphonate and cetyltrimethyl ammonium bromide on mild steel in 0.1 M H₂SO₄ in temperature range of 30 to 60°C was investigated using weight loss method, chemical analysis of solution, scanning electron microscopy, atomic force microscopy and determination of thermodynamic parameters. Inhibiting action of gum acacia is synergistically enhanced on addition of small amount of surfactants. SEM and AFM results confirmed the existence of an adsorbed protective film on the mild steel surface. Thermodynamic parameters reveal that adsorption process is spontaneous and obey Freundlich adsorption isotherm.     

新型复合负载金属-支撑水相催化剂

 复合催化剂SAP/Rh-SiO2中匀相组分和多相组分具有协同作用。本文主要考察V助剂对Rh-V/SiO2多相催化剂和SAP/Rh-V-SiO2复合催化剂1-己烯氢甲酰化性能的影响。实验结果表明：加入助剂V之后,Rh-V/SiO2催化剂的活性（147.2h-1）比Rh/SiO2催化剂的活性（20.8h-1）有很大提高,而复合SAP/Rh-V-SiO2催化剂的活性（594h-1）比SAP/Rh-SiO2催化剂的活性（370.5h-1）提高很多。V有很强的储氢作用,在Rh-V/SiO2催化剂上更容易发生氢溢流,因此该类复合催化剂的作用机理可能是多相催化剂上产生的H和CO溢流等活性物种溢流至烯烃配位的匀相催化剂活性上发生反应,从而促进复合催化剂活性的提高。