Flotation-spectrophotometric determination of trace of germanium with isochromatic dye ion-pairs formed by rhodamine 6G and tetrabromofluorescein

A flotation spectrophotometric method for the determination of germanium with isochromatic dye ion-pairs is described. The molar ratio of germanium to rhodamine 6G to tetrabromofluorescein is 1:5:5. The apparent molar absorptivity is 5.8 x 10(5) l mol(-1) cm(-1) at 531 nm. Beer's law is obeyed over the concentration range of 5.0 x 10(-8)-1.25 x 10(-6) mol l(-1). The proposed method is sensitive and accuracy and can be applied satisfactorily to the determination of germanium in vegetables.     

Controllable fabrication of ZnO nanorods@cellulose membrane with self-cleaning and passive radiative cooling properties for building energy-saving applications

Cellulose - The energy consumption for building cooling occupies non-ignorable part of global energy consumption, causing the increasing aggravation of energy crisis and environmental...     

溴酚蓝和亚甲蓝双显色体系萃取光度法测定铜

向三元络合物[Cu(phen)_3)BPB的二氯乙烷萃取液中,加入KCN水溶液,形成的[Cu(CN)_2)~-和溴酚蓝离子(BPB)进入水相,向其中加入与BPB颜色相近的亚甲蓝(MB)再进行萃取光度测定。因萃取液中[MB_2BPB)和[Cu(CN)_2)MB两者的吸光作用,使本方法具有很高的灵敏度,ε=1.77×10~5L·mol~(-1)·cm~(-1)。铜含量在0～5μg/25ml遵从比耳定律,对含铜量为10~(-8)g/ml的水样测定5次,相对标准偏差为2％。     

Investigation of Absorption Spectra of Bis(alkylxanthato)-platinum(Ⅱ) Complexs

Being widely used as good ligands,xanthates and related compounds have been extensively investigated.However,reports on Pt(Ⅱ) xanthates have been sparse so far.Watt et al.reported the synthesis and characterization of Pt(S_2COR)_2(R=Me,Et),but did not provide any absorption spectra of these complexes.We prepared twelve platinum (Ⅱ) xanthate complexes and examined their absorption spectra in detail.     

氯金酸试纸分光光度法测定水中砷

用氢化物发生法测定水中砷已有很多报道,本文用类似古蔡氏法测砷的氢化物发生装置,使AsH₃与涂在滤纸上的HAuCl₄反应,生成不溶于水的AuAs沉淀,固定蓝紫色圆形斑点的表面积,用纸上双波长分光光度技术测定吸光度。本方法灵敏度高,精密度较好,设备简单,操作方便,检出限为10ng/ml,相对标准偏差小于4％。     

α-氯代脂肪酸对某些稀土的萃取研究

Гавриловаа等^[1]曾报导用α-溴代己酸的氯仿溶液对钐、钕、钆和镥的萃取,其萃取曲线与无取代基的比较向酸性区移动了约1个pH单位。Preston报导了α-溴癸酸的二甲苯溶液对一系列金属离子的萃取,认为所试验的8个稀土金属与α-溴癸酸形成了不溶性的金属络合物^[2]。     

等色染料离子对浮选光度法研究-四溴荧光素*罗丹明6G体系

本文研究了四溴荧光素（ＴＢＦ）、罗丹明６Ｇ（Ｒ６Ｇ）等色染料离子对浮选光度法测定锗、铂和铁的方法。首先将被测金属离子形成的［ＭｅＬｎ（Ｒ６Ｇ）ｍ］（Ｌ：配位体,ｍ、ｎ为整数）有机溶剂浮选物,用碱解析并反萃于水相。而后加入与罗丹明６Ｇ等色的四溴荧光素溶液继续浮选,将形成的等色染料离子对Ｒ６ＧＴＢＦ浮选物溶解于丙酮。于５３０ｎｍ处测定吸光度值。由于２ｍ个染料同时吸收同一波长的光,而提高了方法灵敏度。测定Ｇｅ、Ｐｔ和Ｆｅ的摩尔吸光系数均在１０５Ｌｍｏｌ－１ｃｍ－１以上     

Studies on the stability of four-membered ring chelates Part V. The stability of dialkyl dithiocarbamate chelates

This paper systematically studies the structure and the internal mechanism of the stability of sulphur-coordinated four-membered rings in chelates of dialkyl dithiocarbamate. It was found that the conjugated π electron structure of the free ligand is Π₄⁶, while in the metal chelate it is Π₄⁴. The stable chelates have strong σ- and π-coordinated bonds. The actual strain of the sulphur-coordinated four-membered ring in chelates is not as strong as assumed. It mainly depends on the atomic radius of the metal. The stronger the electronegativity of the metal, the stronger the π-coordinated bond. The stabler the four-membered ring, the weaker the intensity of the C-S vibrational band.     

Characterizations of geometric distributions based on moments

Restricted to certain classes of discrete life distributions, and based on moments, conditional binomial moments, order statistics, spacing or record values, characterizations of geometric distributions are given.This project is supported by the National Natural Science Foundation of China Grant No. 1880492.