Measurement compatibility in size-exclusion chromatography. An intercomparison with a candidate BCR poly(vinyl acetate) reference material

A carefully controlled interlaboratory comparison of analyses by size exclusion chromatography of a poly(vinyl acetate) whole polymer showed that compatible measurements could be made of the molar mass distribution. The characterized sample is available as a Community Bureau of Reference (BCR) test material.     

中国近代化学教育家——张贻侗

张贻侗是中国近代著名的化学教育家。他对北京师范大学、北平大学、西北师范大学及西北大学的化学教育作出了积极贡献,同时他也积极投身科学普及工作。本文介绍了张贻侗的生平简历、科学成就及其思想,以纪念这位对中国化学高等教育做出杰出贡献的化学家。     

UK delivery of traceable chemical measurements in the 21st century: building on the foundation of the VAM programme

The paper discusses the requirements for achieving traceable chemical measurements in the UK. It is emphasised that success will depend on establishing an appropriate UK chemical measurement infrastructure and encouraging reference and field laboratories to make use of it. The demanding requirements of the BIPM Mutual Recognition Arrangement (MRA) also require a point of focus to link UK reference laboratories into international metrology. Two key factors are described which have provided the UK with the means to meet these requirements and which have established a sound basis on which to build a system of traceable chemical measurements in the 21st century. These two factors are LGC's long-standing role as the UK's national centre for analytical chemistry and the development and delivery over many years of the UK's Valid Analytical Measurement (VAM) Programme.     

女化学家艾达·诺达克

德国女化学家艾达·诺达克的亲身经历对理解她那个时代的女科学家具有重要的参照作用和价值。二战前后的德国禁止为已婚妇女提供带薪岗位,女科学家也不例外。在此背景下,婚前的几年包括婚后的30余年里艾达·诺达克与丈夫沃尔特·诺达克长期合作,以此赢得从事科学研究的机会和环境。婚后的艾达·诺达克几乎一直"无薪",甚至无明确的科研岗位,由此导致了不必要的歧视。尽管如此,艾达·诺达克依然取得了重要的科学成就,在铼元素的发现和核裂变预见方面的贡献尤为显著。艾达·诺达克虽获得了一些荣誉和一定的认可,但对她的认识和理解还需继续深入。     

伟大的分析化学家——I．M．Kolthoff

本文简介Ｋｏｌｔｈｏｆ的主要工作并初步探讨了他的学术、教育思想的某些特点     

Differential spectrophotometric determination of micro amounts of metal ions in mixtures

A differential spectrophotometric method is described for the simultaneous determinations of iron and molybdenum, iron and titanium, iron and uranium, molybdenum and titanium, and molybdenum and uranium in mixtures, in a single solution at room temperature. The general method consists in treating the mixture with 5 ml of 1 M sodium acetate and 1 ml of 1% pyrocatechol in 25-ml volumetric flasks. The optical density of color of mixed complexes is determined at the corresponding pair of wavelengths suggested. From the optical density and molar extinction coefficient, the concentration of each ion in mixtures has been calculated. By this procedure, the metal ions can be determined even if they differ by large ratios. Procedures have been extended for the analysis of mixtures containing iron, molybdenum, and titanium (or uranium). These procedures can be applied for the analysis of any type of materials, like minerals, rocks, ores, alloys, steels and refractory materials. Spectra of each complex and their Beer's law were studied in detail. Experiments were also made to show that the calculated and observed optical density of mixture complexes is the same, thereby the additive of optical density of mixtures at each pair of wavelengths suggested for individual determinations of ions have been verified.