Trifluoroethylxanthate as an Analytical Reagent: AAS of Zinc,Antimony and Lead After Coprecipitation of Their Trifluoroethylxanthates onto Microcyrstalline Naphthalene

Abstract

A sensitive method has been developed for the direct atomic absorption spectrometric determination of zinc, antimony and lead after coprecipitation of their trifluoroethylxanthates onto microcrystalline naphthalene. The metal xanthates are quantitatively coprecipitated over the pH ranges: Zn, 5.9–8.4; Sb, 4.0–6.0 and Pb, 4.0–11.0. The solid mass consisting of the metal complex and naphthalene is dissolved in DMF. This solution is aspirated into an air-acetylene flame at 213.9, 217.6 and 217.0nm for Zn, Sb and Pb, respectively. Beer's law is obeyed in the concentration range 2–50, 3–90 and 5–60 μg of Zn, Sb and Pb, respectively in 10ml of the final DMF solution. RSDs are at the ± (0.5–0.6)% level (n=10). The concentration for 1% absorption is 0.019, 0.035 and 0.060μg/ml for Zn, Sb and Pb, respectively. The method is suitable for the preconcentration of the metals from a larger volume of the aqueous phase, and has been employed for their determination in standard reference materials. It may be employed for the simultaneous determination of Zn, Pb and Sb in a solution by pH control.     

Zur Methodik der Messung der Aktivität von umschlossenen γ-Strahlungsquellen mittels Ionisationskammern

In der Arbeit wird über eine Empfehlung zur Methodik der Weitergabe der Aktivitätseinheit für umschlossene γ-Strahlungsquellen von den Normalen der metrologischen Slaatsämter der UdSSR (WNIIM) und der DDR (ASMW) an Normale niederer Ordnung berichtet. Die Weitergabe der Aktivitätseinheit geschieht durch Vergleich mittels Ionisationskammern. Die Empfehlung bezieht sich auch auf solche Fälle, in denen neben dem Hauptnuklid ein Verunreinigungsnuklid in der Quelle enthalten ist, sowie auf solche, bei denen unterschiedlicher Aufbau der zu vergleichenden Quellen vorliegt. Auβerdem umfaβt die Empfehlung die Methode der Fehlerrechnung.     

Immobilization of Antibodies on Magnetic Carbonaceous Microspheres for Selective Enrichment of Lysine‐acetylated Proteins and Peptides

Lysine acetylation is a dynamic and reversible modification, which has been proved to be a key posttranslational modification in cellular regulation. However, the low amounts of the acetylated proteins could hardly be detected before enrichment. In this study, for the first time, antibody‐immobilized magnetic carbonaceous microspheres were developed for selective enrichment of acetylated proteins and peptides. At first, standard proteins composed of acetylated bovine serum albumin, myoglobin, α‐casein and ovalbumin were used as model proteins to verify the enrichment efficiency. Then, the synthesized peptide was employed to confirm the selectivity of the method. Besides, the antibody‐immobilized magnetic particles were successfully applied to analyze mouse mitochondrial proteins. After database search, 29 acetylated sites in 26 proteins were identi?ed.     

Effect of Temperature on Henry's Constant in Simple Mixtures

Abstract

The molecular theory of dense fluids is progressing rapidly and its extension to mixtures is well underway. The purpose of this note is to call attention to a possibly serious difficulty in comparing experimental Henry's constants with those calculated from theory. The difficulty arises because whereas theorists choose temperature and density as independent variables, experimental equilibrium measurements on mixtures are often made along the saturation line where (at fixed composition) temperature and density are not both independent variables. Unless Henry's constants are defined with care, the effect of temperature on Henry's constants calculated from molecular theory may be qualitatively different from that observed.     

糖胺聚糖的荧光标记及其与硫酸软骨素抗体的相互作用

以1-乙基-3-(3-二甲基氨丙基)-碳化二亚胺和N-羟基琥珀酰亚胺为催化剂,将糖胺聚糖(肝素、硫酸乙酰肝素、硫酸软骨素A,B,C,D,E)中糖醛酸的羧基与氨基荧光素中氨基偶联,分别得到各荧光标记糖胺聚糖.将标记糖胺聚糖用点样仪点在硝酸纤维素包被玻璃芯片上,分别探讨其在硝酸纤维素薄膜上的保留率及其与硫酸软骨素抗体(克隆...     

乳胶凝集法快速检测猪圆环病毒2型

发展了一种简单、快速、灵敏的乳胶凝集法用于猪圆环病毒2M的检测.合成了带有磺酸基的三元聚合物乳胶微球,通过静电相互作用,将猪圆环病毒2型单克隆抗体吸附到乳胶微球表面,形成乳胶抗体复合物诊断试剂.乳胶抗体复合物诊断试剂表面抗体与病毒表面抗原发生特异性反应,促使分散的乳胶微球凝集在一起,出现肉眼可见的凝集现象,而与去离子水...     

差示扫描量热法对芝麻酚纯度标准物质的定值

建立了采用差示扫描量热法对芝麻酚纯度标准物质的定值及不确定度评价的数学模型、有效检测技术和分析方法.采用差示扫描量热法测量芝麻酚样品纯度的实验条件为升温速率3.0 K/min,称样量3.4～4.7 mg,炉内气体为静态空气.对通过均匀性检验和长期稳定性考察的芝麻酚纯度标准物质进行定值和不确定度评价,同时采用高效液相色谱...     

检测/校准实验室仪器设备及标准物质期间核查实施方法

对检测/校准实验室仪器设备及标准物质期间核查的具体实施进行了讨论,重点介绍编写期间核查作业指导书需明确的内容,包括明确核查对象、确定核查项目、选择核查方法、规定核查间隔、获取核查判据及如何判定对核查不合格的处置.指出既能利用期间核查确保仪器设备及标准物质的可靠性,又不浪费人力物力的措施.