Vanadametry

Summary We have found that sodium vanadate oxidises hydroxylamine quantitatively and rapidly to nitrous oxide, even at the room temperature, if the reaction is carried out in 5–6 N hydrochloric acid medium using copper sulphate as catalyst.One of the authors, K.Bhaskara Rao, desires to thank the Ministry of Education, Government of India, for the award of a ResearchScholarship, and the authorities of the Andhra University for providing the research facilities.See also Z. analyt. Chem.156, 180 (1957).     

Vanadametry

Summary A vanadametric method has been developed which has definite advantages over iodimetric assay and bromimetric assay for the estimation of isonicotinic acid hydrazide in tablets. The excepients such as lactose, glucose and starch do not interfere in the estimation of the hydrazide with vanadate. Unlike iodimetric and bromimetric assays, the vanadametric assay is rapid.See also Z. analyt. Chem. 160, 117 (1958).     

Vanadametry

Summary A vanadametric procedure has now been developed for the accurate determination of thiocyanate. Unlike most other oxidimetric methods, the vanadametric method is free from the interference of oxygen of the air.See also: Z. analyt. Chem. 156, 181 (1957).     

Vanadametry

Summary A new vanadametric procedure has been now proposed for the determination of antimony(III). Trivalent antimony is quantitatively oxidised in the presence of excess vanadic acid in about 5 min at 98–100° C in 1.0 N sulphuric acid medium, provided iodine monochloride is used as catalyst.The author wishes to express his grateful thanks to the Ministry of Education, Government of India, for the award of a Research Scholarship and the authorities of the Andhra University for providing research facilities.See also: Z. analyt. Chem. 156, 180 (1957); 157, 178, 181 (1957).     

18／8型不锈钢在受力形变条件下腐蚀电化学行为的研究

应用电化学稳态技术、电化交流阻、抗微区电化学技术及扫描电等方法，研究１８／８型不锈钢在Ｎａ２Ｓ２Ｏ３稀溶液中，受外力形变条件下，的腐蚀电化学行为，结果表明，力学因素可使表面腐蚀电化学活性增加，表面微裂纹的发生、消失和再钝化的动态过程，同时受电位和拉应力的影响；点腐蚀可优先发生在应力集中位置，点蚀的发展可能诱导不锈钢的应力腐蚀开裂。     

Thiosulphate in the Wollak procedure-analysis and kinetics in acidic formaldehyde medium

The Wollak procedure for the determination of the sum of dithionite and thiosulphate has been investigated. Analytical data and a kinetic study confirm that thiosulphate reacts with formaldehyde under acidic conditions. Both pH and CH(2)O concentration affect the results and satisfactory analysis can be performed only if the pH of the initial sample-formaldehyde mixture remains high enough.     

毛细管电泳对微生物代谢中硫酸根和硫代硫酸根的分离与测定

建立了微生物代谢中硫酸根和硫代硫酸根的毛细管电泳分析方法．在选定实验条件下，各种阴离子（Ｓ２Ｏ２－３、ＳＯ２－４、ＣＩ－、ＮＯ－３、ＰＯ３－４）在４ ｍｉｎ内达到完全分离，其中 Ｓ２Ｏ２－３和ＳＯ２－４迁移时间的相对标准偏差小于１％，峰面积的相对标准偏差小于５％．测定了４种菌株分别在两种培养基中的Ｓ２Ｏ２－３和ＳＯ２－４浓度随培养时间的变化．结果表明，其中一菌株在ＳＫ基中对Ｓ２Ｏ２－３有明显的氧化作用．     

Estimation of metals as sulphides : Estimation of platinum metals

1. It has been shown that all the platinum metals with the exception of osmium can be estimated as sulphide if the solution containing the metal is treated with a large excess of alkali sulphide followed by excess of acetic acid and ammonium acetate. The precipitate of the sulphide can be washed with water, alcohol and ether successively, dried in a vacuum desiccator, and weighed. 2. By the above procedure it is possible to complete the analysis for all the platinum metals within 3 hours, whereas the procedures described in the literature require much longer time —in many cases more than 24 hours. 3. The precipitates obtained by the older procedures were very sticky and difficult to filter. By carrying out the precipitation in the presence of acetic acid and ammonium acetate it has been possible to obtain the precipitate in an easily filterable form. 4. The above method not only provides a very convenient general method of estimating the platinum metals, but also throws interesting light on the formation of thiosalts and the precipitation of sulphides by their decomposition.     

Estimation of dichlor-acetaldehyde

Summary Dichloracetaldehyde has been estimated by alkalimetric, argentometric and iodometric procedure. A mechanism has been proposed for its hydrolysis.Sincere thanks of the authors are due to Professor S. S. Joshi, Head of the Chemistry Department, Banaras Hindu University, for guidance.     

Estimation of palladium

Summary In presence of tartaric acid and ammonium chloride, quinaldinic acid quantitively precipitates palladium from a hot solution at a p_H range 3 to 7 whereas other ions such as arsenic (As³⁺ and As⁵⁺), mercury (Hg²⁺), cadmium, bismuth, antimony, iron, chromium, aluminium, beryllium, thorium, cerium (Ce³⁺), titanium, zirconium, uranium (UO₂ ²⁺), vanadate, molybdate, tungstate, cobalt, nickel, manganese, magnesium, calcium, barium and strontium remain in solution. The palladium complex is quite insoluble in hot water and can be dried at any temperature up to a maximum of 353° C when it decomposes.     

Estimation of silica

5,6-Benzoquinaldine and 8-hydroxyquinaldine have been used as organic bases for the quantitative precipitation of silica as silicomolybdic salts of the bases under suitable conditions of acidity. The salts, being stable and non-hygroscopic, may be directly weighed after drying at 110–150° C or alternatively may be ignited at 550° C with free access of air to silicomolybdic anhydride.