Monitoring of the synthesis ofcis andtrans ruthenium macrocyclic complexes by reversed-phase high-performance liquid chromatography

Summary The synthesis of the complex [Ru(cyclam)Cl₂]Cl (cyclam=1,4,8,11-tetraazacyclotetradecane) has been monitored by reversed-phase high-performance liquid chromatography. The analytical results obtained during the reaction have shown that it is feasible to identify and isolate the two isomerscis- andtrans- [Ru(cyclam)-Cl₂]Cl. The use of an octadecylsiloxy preparative column enabled the separation and purification of these two isomers and the compounds have been obtained in high purity. The use of reversed-phase high-performance liquid chromatography has afforded complete analytical control of the syntheses of saturated nitrogendonor macrocyclic complexes of ruthenium, enabling identification of thecis andtrans isomers of the complex [Ru(cyclam)Cl₂]Cl.     

顺序注射环定量光度法在线测定水中总铁

选用邻菲啰啉作为显色剂,采用顺序注射环定量(SIA)光度法,结合一整套系统的PLC程序,成功建立了测定水中总铁的新方法.实验过程中对各条件进行了优化,在最优条件下,体系的检测范围为0～10 mg/L,线性回归方程为A=0.0995c+0.0421(c:mg/L,n=8),相关系数r为0.999 6,方法检出限为0.02 mg/L,相对标准偏差(RSD)为2.3%(0.50 mg/L,n=11)和1.7%(2.00 mg/L,n=11),实际水样的加标回收率为97.1%～102.0%.     

On-line monitoring of all-acrylic emulsion polymerization reactors by Raman spectroscopy

Fourier Transform Raman spectroscopy was used as an on-line sensor in order to monitor high solids content (50 wt%) n-BA/MMA emulsion copolymerization reactions. Due to the similarity of the chemical structure of the monomers, no separate bands could be detected for each monomer, and therefore a multivariate calibration technique was required (Partial Least Squares Regression, PLSR). Using experimental data from several semi-batch reactions independent PLSR models were built for the solids content, cumulative copolymer composition and unreacted amounts of n-BA and MMA. Those models were experimentally validated by monitoring reactions not used for calibration. It is demonstrated that FT-Raman spectroscopy can be successfully applied to on-line monitor emulsion polymerization reactors. This technique also shows a high potential for process control purposes because independent information about several molecular properties can be obtained from a single apparatus.     

Voice characteristics, effects of voice therapy, and long-term follow-up of contact granuloma patients

This study evaluates the laryngoscopic findings and voice characteristics of male contact granuloma patients before and after voice therapy and at a follow-up about 9 years later. Pre- and posttherapy recordings as well as follow-up recordings were made for 19 granuloma patients. Pretherapy revealed the most salient perceptual voice characteristics were low pitch, monotony, and a high degree of vocal fry and hyperfunction. Interjudge reliability for these traits was high. Immediately following therapy the healed patients (n = 10) had a decrease in hyperfunction, vocal fry, and monotony, while the unhealed patients (n = 9) had an increase in hyperfunction and vocal fry decreased only marginally. Monotony decreased significantly in this group. As regards the acoustic analyses, no significant differences were found in mean fundamental frequency (F₀) or perturbation. At the follow-up assessment 4 patients had granuloma while 15 had normal laryngeal status. Perceptually their voice characteristics resembled those pretherapy independently of the laryngeal findings. The results suggest that reduced hyperfunction and decreased vocal fry may create better circumstances for the healing process at the posterior glottis.     

以史为鉴——化学科普中的人文素养教育

中国古代历史中蕴含着丰富的化学史资源,对这些资源的挖掘、解读,形成化学科普题材,既是化学教育的需要,也是加强思想政治教育背景下课程思政的现实要求。以寒食散为例,探讨中国古代化学史资源所蕴含的人文素养教育价值,认为化学科普中汲取历史资源,不仅增加了科普的趣味性,有利于向公众普及化学知识,还有助于公众树立正确的世界观和价值观。     

Correlation between Polymer Particle Size and in‐situ NIR Spectra

This work describes the estimation of polymer particle size from NIR spectra collected in situ and online in an automated reactor. A good linearity between spectra and average polymer particle diameter is found. The multivariate linear model is also tested with an independent data set not used in the model fitting. Despite varying monomer and polymer concentrations and temperature changes along the process, the average particle sizes are well predicted and can be monitored by NIR spectroscopy during emulsion polymerization reactions.

Evolution of average particle diameter with polymer content for three different BA/Sty semi‐continuous emulsion polymerization reactions. Open symbols correspond to spectra used in the model fitting and solid symbols to the test data set. The different symbol types correspond to the three different reactions.     

16种有机标准物质的研制

介绍16种有机标准物质的研制方法。16种有机标准物质与US EPA、US Supelco及国家标准物质研究中心的同类标准物质比较,均匀性、稳定性及定值准确性均达到或优于其性能指标,符合国家计量技术规范的要求。     

研制动力煤标准物质的质量保证

从原料煤的均匀性、均匀性检验方法及判断标准、定值程序和定值方法、实验数据的统计处理、煤标准物质的稳定性等方面,介绍了研制动力煤标准物质的质量保证措施。     

在线分析技术在中国的发展

在线分析技术由于其具有实时、准确、高效的特点,近年来得到快速发展,已被广泛应用于环境、矿业、冶金、生物医药和食品等领域。重点介绍了国内X射线荧光光谱、激光诱导击穿光谱、瞬发γ中子活化、双能量γ射线透射、原子荧光光谱、近红外光谱和质谱法等在线分析技术近十年来的发展和应用情况,并对在线分析技术未来发展趋势进行了展望。     

气相色谱-质谱法分析山楂果中的有机酸

山楂(Hawthorn),别名红果,蔷薇科山楂属(Crataegus)植物,山楂果营养丰富,是最早被列入食药兼用的水果之一,具有消食化滞,行气散瘀等功效。山楂果中起消食导滞作用的有效成分是有机酸。本文对文献的实验条件进行合理改进,用GC—MS法对河南辉县和桐柏山两地山楂果中有机酸成分进行了系统分析,各有机酸成分得到有效分离;并利用选择离子方法测定了其中8种主要有机酸的含量,以期对山楂果的食用、药用价值以及开发研制功能性保健食品提供科学依据。