双显色剂高灵敏协同显色反应的研究——钴(Ⅲ)-亚硝基R盐-结晶紫体系

在水溶液中钴(Ⅱ)与亚硝基R盐所形成的配合阴离子可以与有机碱阳离子(结晶紫)缔合形成中性缔合分子。在聚乙烯醇存在下,配合物可稳定存在于水溶液中。钴(Ⅲ)-亚硝基R盐-结晶紫配合物在510nm处有一最大吸收,摩尔吸光系数ε_(510)=1.47×l0~5L·mol~(-1)·cm(-1)。配合物中各组分的摩尔比为:Co:R:CV=1:3:6。反应具有较高的选择性,采用双峰双波长法测定钴可使灵敏度得到进一步提高,相应的摩尔吸光系数ε_(510-640)=4.09×10~5L·mol~(-1)·cm~(-1)。方法用于合成试样中钴的测定,结果满意。     

Influence of CTAB/alkanol/cyclohexane w/o microemulsions on the basic hydrolysis of crystal violet

The basic hydrolysis of crystal violet has been studied in w/o microemulsions of the CTAB/alkanols/cyclohexane system (alkanols: 1-butanol and 1-hexanol). The reaction can be considered to occur in the water phase of the droplets and from the rate constant the apparent dielectric constant of the water phase was determined. The cyclohexane incorporation in the system produces a decrease in the effective dielectric constant of the water phase and in the specific conductivity.     

Study of the concentration and separation of cadmium with microcrystalline phenolphthalein modified by crystal violet

A new method for cadmium separation and concentration with microcrystalline phenolphthalein modified by crystal violet (CV) was developed in the paper. In the presence of potassium iodide (KI) and CV, cadmium are quantitatively absorbed on microcrystalline phenolphthalein in the pH range 1.0-6.0 as the forms of water-insoluble ion-associated complexes (CdI₃⁻)·(CV⁺) and (CdI₄²⁻)·(CV⁺)₂. Effect of different parameters such as phenolphthalein amount, stirring time, the concentration of CV and KI, various salts and metal ions was studied in detail. During the present study, a significant enhancement of the extraction of cadmium was observed. Cd(II) can be completely separated from Zn(II), Fe(II), Co(II), Ni(II), Mn(II), Cr(III) and Al(III) in this microcrystalline system and well concentrated without the interference of these metal ions at high level. The possible reactive mechanism of cadmium concentration has been discussed. Analytical results obtained by this new method were very gratifying.     

Simultaneous Determination of Aluminum and Iron in High Salt Content Matrices by Adsorptive Stripping Voltammetry. Application to Dialysis Fluids

A new analytical procedure for the simultaneous determination of aluminum(III) and iron(II) in two kinds of dialysis fluids (peritoneal and hemodialysis fluids) by differential pulse adsorptive stripping voltammetry (DPAdSV) is described. The voltammetric measurements were performed using, as working electrode, a stationary mercury electrode, and a platinum electrode and a Ag|AgCl|KCl_(sat.) electrode as auxiliary and reference electrodes, respectively, employing acetate buffer solutions at different pH as supporting electrolyte. As complexing agents, Solochrome Violet RS, Palatine Chrome Black 6BN, Chromazurol S and Eriochrome Black T were employed. For both elements, the accuracy, expressed as relative recovery R%, was very satisfactory being in the range 94–105%, the precision as repeatability, expressed as relative standard deviation s_r%, was lower than 6%, while the limits of detection were of the order of a few units of μg/L. The analytical voltammetric procedure has been validated by comparison with spectroscopic (graphite furnace atomic absorption spectroscopy, GFAAS) measurements.     

痕量铁的光化学伏安分析法及其应用研究

在稀硫酸介质中及活化剂草酸存在下，痕量铁（Ⅲ）对结晶紫光化学褪色反应有强烈催化作用，结晶紫的光化学反应产物于－０．７０产生一灵敏的２．５次微分级谱波。     

Determination of cationic polyelectrolytes using a photometric titration with crystal violet as a color indicator

The reaction of the cationic dye, crystal violet (CV) with the anionic polyelectrolytes such as potassium poly (vinyl sulfate) (PVSK) results in a decrease of the absorbance of CV at the maximum absorption wavelength (590 nm). This change of the absorption spectra of the CV has been already applied to the determination of anionic polyelectrolytes using flow injection analysis method. In this paper, CV was applied to the indicator for the determination of cationic polyelectrolytes such as poly (diallyldimethylammonium chloride) (Cat-floc) by photometric titration, using a PVSK solution as a titrant. The end-point of the titration is detected as the break point of the titration curve. A linear relationship between the concentration of cationic polyelectrolyte and the end-point volume of the titrant exists in the concentration range from 0 to 5×10⁻⁵ eq. mol dm⁻³ for Cat-floc, glycol chitosan and methylglycol chitosan. The effects of the concentration of CV and coexisting electrolytes in the sample solution and the effect of pH of the sample solution on the degree of the change of absorbance at the end-point were also examined.     

无机阴离子的毛细管电泳分析

本文研究了常见无机阴离子的毛细管电泳规律，考察了分离电压、电解质熔液组成、浓度、ｐＨ值等对分离的影响，建立了高效、快速的无机阴离子毛细管电泳分析方法。在选定的实验条件下，各种常见无机阴离子在５ｍｉｎ内达到完全分离，对Ｂｒ＾－和Ｃｌ＾－的分离柱效每米可达７６万理论板数。迁移时间的相对标准偏差小于１％，峰面积的相对标准偏差小于５％，各离子的最低检测浓度为０．０５￣０．５μｇ／ｍｌ。     

Application of HPLC to measure vanadium in environmental,biological and clinical matrices

Vanadate and vanadium compounds exist in many environmental, biological and clinical matrices, and despite the need only limited progress has been made on the analysis of vanadium compounds. The vanadium coordination chemistry of different oxidation states is known, and the result of the characterization and speciation analysis depends on the subsequent chemistry and the methods of analysis. Many studies have used a range of methods for the characterization and determination of metal ions in a variety of materials. One successful technique is high performance liquid chromatography (HPLC) that has been used mainly for measuring total vanadium level and metal speciation. Some cases have been reported where complexes of different oxidation states of vanadium have been separated by HPLC. Specifically reversed phase (RP) HPLC has frequently been used for the measurement of vanadium. Other HPLC methods such as normal phase, anion-exchange, cation-exchange, size exclusion and other RP-HPLC modes such as, ion-pair and micellar have been used to separate selected vanadium compounds. We will present a review that summarizes and critically analyzes the reported methods for analysis of vanadium salts and vanadium compounds in different sample matrices. We will compare various HPLC methods and modes including sample preparation, chelating reagents, mobile phase and detection methods. The comparison will allow us to identify the best analytical HPLC method and mode for measuring vanadium levels and what information such methods provide with regard to speciation and quantitation of the vanadium compounds.     

A Sensitive Spectrophotometric Determination of Nitrite in Water and Soil

A highly sensitive spectrophotometric method for the determination of nitrite in water and soil has been developed. The reaction of nitrite with acidified potassium iodide to liberate iodine which oxidizes leuco‐crystal violet (LCV) to form crystal violet having absorption maxima at 590 nm forms the bases of this method. In aqueous medium the system obeys Beer's law in the range of 0.1 to 1.0 μg per 25 mL (0.004–0.04 ppm), while in an extractive system the range is 0.025–0.25 μg in 100 mL (0.00025–0.0025 ppm). The molar absorptivity and Sandell's sensitivity were found to be 1.54 × 10⁶ 1 mol^?1 cm^?1 and 44 pg cm^?2, respectively.     

离子交换树脂相分光光度法测定水中痕量铋

利用离子交换树脂相通过光度法测定痕量铋。铋离子在碱性介质中与邻苯二酚紫形成紫色络合物将其富集在苯乙烯阴离子交换树脂上,通过制作成薄层直接光度法测定。本法操作简便,装皿容易,选择性好,精密度高(测定5μgBi3 5次,RSD=3.8%),铋浓度在0~10μg(50ml)时与吸光度呈线性关系,线性回归方程为A=0.010 0.075C(μg/50ml),相关系数r=0.9997,铋的回收率为98%~99%,检出限为3.2μg/L,用于水中痕量铋的测定,结果满意。