用铜(Ⅱ)-过氧化氢-二苯碳酰二肼/氯仿体系催化-萃取光度法测定铜

本文研究了在弱酸性介质中，利用铜（Ⅱ）催化过氧化氢氧化二苯碳酸二肼生成二苯卡巴腙的指示反应与铜（Ⅱ）和二苯卡巴腙的显色反应相结合，建立了催化-萃取光度法测定铜的新方法。方法的线性范围为5．0～500μg／L，表观摩尔吸光系数为8．8×104L·mol－1·cm-1。用于水、铝合金和岩石中铜的测定。结果满意。     

Persulfate Oxidation and Diphenylcarbazide Photometric Determination of Chromium in Super Alloys

The quantitative analysis of Cr in super alloys with the presence of a wide variety of elements, Al, B, C, Co, Cu, Hf, Fe, Mn, Mo, Ni, Nb, P, Si, S, Ti, Ta, W, Zr; and trace amounts (a few ppm) of Pb, Se, Bi, Tl and Te has been studied. Persulfate oxidation and diphenylcarbazide photometric method were studied with the purpose of developing a relatively fast and reliable measurement for Cr by wet chemical analysis. The results indicate that the latter is supperior to the former in practical view. In the photometric method, solid sample (0.1g alloys) when treated with HClO₄ and H₂SO₄ took ca. 72 hrs. for complete dissolution. When treated with HCl followed by HNO₃, 0.1 g alloys were completely dissolved within 1&1/2; hours. The best experimental conditions for diphenylcarbazide photometric determination of Cr was thus established. Photometric determination of Cr complexes was made at 540 nm.     

铬络合物的固相萃取富集和分光光度法测定

本文提出了用聚乙烯粉末固相萃取铬络合物的方法。在强酸性介质中，Ｃｒ（Ⅵ）与二苯碳酰二肼发生氧化还原反应，反应产物能结合生成稳定的络合物。     

二苯碳酰二肼光度法测定铬(Ⅵ):不足及改进

有毒重金属铬（Ⅵ）的测定是环境、化学等专业重要的实验内容，教材常用的测定方法是国标二苯碳酰二肼分光光度法（GB7467—1987）。国标方法存在使用挥发性有毒溶剂、操作繁琐等不足，对环境和分析人员不利。对国标方法进行改进，结果证明：可以用乙醇代替有毒的丙酮配制二苯碳酰胺二肼显色剂，用盐酸代替硫酸和磷酸的混合酸，并将盐酸直接加入显色剂中，分析时可一次加入，既简化了操作步骤，提高了工作效率，又减少了显色剂用量，有利于环境和人员健康。将改进的方法应用于废水中六价铬的测定，并与原子吸收光谱法进行比较，结果无显著性差异，能够确保水样中六价铬测定的精密度和准确度。     

Preconcentration and Spectrophotometric Determination of Chromium (VI) and Total Chromium in Drinking Water by the Sorption of Chromium Diphenylcarbazone with Surfactant Coated Alumina

Abstract

A simple and inexpensive method for determining chromium (VI) in drinking water by spectrophotometry after preconcentration with sodium dodecyl sulphate (SDS) coated alumina column is described. Chromium(VI) is reacted with diphenylcarbazide (DPC) and the Cr-DPC complex is quantitatively adsorbed onto a SDS coated alumina column from 800 ml of sample solution. The complex is then eluted with a 8 ml mixture of methanol, acetone and hydrochloric acid and determined by spectrophotometry. Total chromium can be determined after oxidation of chromium (III) to chromium (VI) by KMnO₄. The relative standard deviation (10 replicate analyses) at the 10 μg l^?1 of chromium (VI) and 10 μg l^?1 of total chromium were 3.5% and 3.4% and corresponding limits of detection (based on 3 σ) were 0.040 μg l^?1 and 0.033 μg l^?1, respectively.     

Field Determination of Cr(VI) in Water At Low PPB Level

Abstract

Methods for determining chromium (VI) at the ppb level, in tap water and ground water, were developed. These make use of anion exchange resin beads or anion exchange membrane filters to preconcentrate the Cr(VI) and separate it from interfering cations. The color is developed by reaction with diphenylcarbazide and the quantitation is carried out using a portable UV/Vis spectrometer, in the liquid or solid phase, or by visual color matching. These methods are suitable for use in the field.     

新型氯化三苯基锡(1,4-二氢-2,3-二苯基四氮唑酮)配合物的合成及其性能

以三苯基氯化锡和二苯碳酰二肼为原料,在乙醇-钠中反应合成了一个新型的氯化三苯基锡(1,4-二氢-2,3-二苯基四氮唑酮)配合物（1）,其结构经FT-IR,元素分析和X-射线单晶衍射表征。结果表明：1（CCDC: 1 445 377）属单斜晶系,P21/c空间群,晶胞参数a=1.393 2(6) nm, b=1.097 3(5) nm, c=1.933 7(8) nm, β=110.219(9) ,V= 2.77 4(2) nm³, Z=4, Dc=1.498 g·cm^-3, F(000)=1 264, R₁=0.028 8, wR₂=0.064 6。中心Sn为五配位三角双锥构型。研究了1的荧光性质、热稳定性、电化学性质和体外抗癌活性。结果表明:1在100 ℃下较稳定; 1在400 nm(λ_ex=320 nm)处有弱荧光峰;c(1)=5 μg·mL^-1时,对HeLa细胞株增殖的抑制率为93.70%。     

油漆、油墨中Pb、Cd、Cr(Ⅲ)、Cr(Ⅵ)含量测定

建立了1种检测油漆、油墨中Pb、Cd、Cr(Ⅲ)、Cr(Ⅵ)含量的方法.用电感耦合等离子体发射光谱法(ICPAES)测定其中的铅、镉、总铬含量,方法的精密度小于6%,加标回收率为96.2%~100.2%.用二苯碳酰二肼分光光度法测定Cr(Ⅵ),其方法的加标回收率为80.0%~90.0%.X射线光电子能谱法(XPS)分析油墨中铬的形态主要为三价.实验结果表明:油墨中Pb含量低于0.20 mg/kg,Cd含量低于0.04 mg/kg,Cr(Ⅵ)含量低于2.00 mg/kg;油漆中Cd含量低于6.00 mg/kg,均符合ASTM F963-2011美国玩具产品标准要求.8种油漆样品中,有6种铅含量超过90 mg/kg,有1种油漆Cr(Ⅵ)含量高达1.33×104mg/kg,不符合ASTM F963-2011标准.Pb、Cd、Cr(Ⅵ)检出限分别为0.04、0.2、2.0 mg/kg.     

Crystal Structure and Spectroscopic Studies of Diphenylcarbazide Acetonitrile Solvate,(PhNHNH)_2C=O·CH_3CN

1INTRODUCTIONDiphenylcarbazideisanartificialelectrondonormaterialusedfrequentlyinanalyticalchemi-stryforcalorimetricdeterminationofchromiumandasensitivereagentformetalions(mercuryandcadmium)[1].Ithasvariousapplications,especiallyinthefieldsofbiophysicsandmicrobiology.Withthehelpofexogenouselectrondonors,diphenylcar-bazidephotointheactivatedsitesontheelectrontransferchainweredelineated[2].Diphenylcarbazideisalsoanartificialdonorduringchargeseparationinthephotochemicalreactions[3]andphotosy…     

萃取催化光度法测定痕量锰及其反应机理

研究了在弱酸性介质中，以氨三乙酸为活化剂，利用锰（Ⅱ）催化高碘酸钾氧化二苯卡巴肼的指示反应，用卒取平衡控制反应时间和水相中二苯卡巴肼的浓度及反应程度，建立了萃取催化光度法测定痕量锰的新方法。方法的线性范围为０．１０～５０μｇ／Ｌ；检出限为８．７ｘ－８ｇ／Ｌ。用于水、茶叶和粮食中痕量锰的测定，结果满意。探讨了反应机理，建立了动力学方程式。