毛细管电泳中样品在线预富集方法

本文对高效毛细管电泳中样品在线预富集方法作了评述，包括瞬间等速电泳，反流速电泳，场放大进样，场放大排除基体和固相萃取等技术，引用文献81篇。     

Ion-Exchange Preconcentration and Separation of Trace mounts of Platinum and Palladium

ABSTRACT

The preconcentration and separation of platinum and palladium from weakly acidic solution (pH=4) were done on microcolumn packed with Cellex-T resin. Selective platinum elution from the column was performed with 0.01 mol/l glycine solution at pH=12, while for palladium elution 1.2 mol/l thiourea (pH=0.5) or 4.0 mol/l potassium thiocyanate (pH=1) may be used. As the detection technique was used either FAAS or GFAAS, depending on the concentration of studied metals in the eluate.     

Determination of Aluminum Traces in Hemodialysis and Tap Water Using Standard Method's Procedure Modified and Flow Injection Ionic Exchange Preconcentration

Abstract

A procedure for the spectrophotometric determination of aluminum traces in water using a flow injection (FI) preconcentration system has been proposed. The flow system was made up of a peristaltic pump, an injector‐commutator, and a minicolumn filled with 300.0 mg of Amberlite IR‐120 cationic exchange resin. After the preconcentration step, aluminum was eluted by a 4.0 mol l^?1 HCl solution. In a second stage, out of the flow system, the eluate was neutralized with a 4.0 mol l^?1 NaOH solution. The aluminum was submitted to the reaction with eriochrome cyanine to form a chelate in solution buffered to pH 5.85, according to the Standard Method's procedure with some modifications, and this was followed by spectrophotometric detection. Chemical and flow variables were studied in the preconcentration system. The precision of the proposed method was calculated for a solution containing 46.8 µg l^?1 of Al(III), when 40.0 ml of solution were preconcentrated (n=7), and their respective relative standard deviation (RSD) was 1.8%. The detection limit obtained was 1.7 µg l^?1 of Al(III) (sample volume=40.0 ml). The proposed method was successful in determining aluminum in water certified reference material.     

Determination of Iron (II) in Water by a Spectrophotometric Method After Preconcentration on an Organic Solvent-Soluble Membrane Filter

Abstract

A solvent-soluble membrane filter is proposed for a simple and rapid preconcentration and spectrophotometric determination of iron (II), which was collected on a nitrocellulose membrane filter as an ion-associate of the cationic complex of iron (II)-1,10-phenanthroline with an anionic surfactant of dodecyl sulfate. The ion-associate collected was dissolved in 5 ml of 2-methoxyethanol together with the filter. The color intensity due to the ion-associate in the resulting solution was measured at 510 nm against a reagent blank. Beer's law is obeyed in the range 1–15 μg Fe (II) in 5 ml of solvent with excellent reproducibility, and detection limits better than 0.5 μg dm^?3 as Fe (II) can be achieved. The diverse components normally present in water do not interfere when proper masking reagent is added. The proposed method has been applied to the analysis of water samples from several sources such as river water, ground water and tapwater samples, the recoveries of the iron (II) added to the samples are quantitative, and results found are satisfactory.     

Chemical removal of humic substances interfering with the on-line solid-phase extraction—Liquid chromatographic determination of polar water pollutants

Summary Different methods for removing interference by humic substances in the analysis of polar pollutants have been compared in the analysis of environmental water by solid-phase extraction (SPE) with a chemically modified polymeric resin coupled on-line to liquid chromatography with UV detection. The methods were based on the use of chemical reagents. The best method was found to be addition of sodium sulphite to humic-containing water before SPE. The appropriate amount of sulphite depends on the amount of humic substances dissolved in the sample—for analysis of 50 mL tap and Ebro river water, respectively, 250 μL and 500 μL 10 % Na₂SO₃ solution had to be added. In both cases, the recovery values after chemical treatment were similar to those when a Milli-Q-quality water standard was analysed.     

Preconcentration of poorly volatile impurities in thin-layer chromatography by thermodesorption of a volatile matrix

A method for preconcentration of poorly volatile impurities by continuous thermodesorption of the major component on a TLC plate is proposed. The method provides multiple (200–500) concentration of the organic impurities present in the initial solution. A simple device for such concentration is suggested. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2075–2076, October, 1998.     

印染废水的植物修复及在线监测技术研究

采用空心莲子草对印染废水进行修复,研究净化效果,并利用在线监测技术对植物修复前后的印染废水中氨氮、COD、TOC指标进行测定。结果表明：在线监测技术成熟,植物修复印染废水可行。     

On-line preconcentration using dual mini-columns for the speciation of chromium(III) and chromium(VI) and its application to water samples as studied by inductively coupled plasma-atomic emission spectrometry

On-line preconcentration system for the selective, sensitive and simultaneous determination of chromium species was investigated. Dual mini-columns containing chelating resin were utilized for the speciation and preconcentration of Cr(III) and Cr(VI) in water samples. In this system, Cr(III) was collected on first column packed with iminodiacetate resin. Cr(VI) in the effluent from the first column was reduced to Cr(III), which was collected on the second column packed with iminodiacetate resin. Hydroxyammonium chloride was examined as a potential reducing agent for Cr(VI) to Cr(III).The effects of pH, sample flow rate, column length, and interfering ions on the recoveries of Cr(III) were carefully studied. Five millilitres of a sample solution was introduced into the system. The collected species were then sequentially washed by 1 M ammonium acetate, eluted by 2 M nitric acid and measured by ICP-AES. The detection limit for Cr(III) and Cr(VI) was 0.08 and 0.15 μg l⁻¹, respectively. The total analysis time was about 9.4 min.The developed method was successfully applied to the speciation of chromium in river, tap water and wastewater samples with satisfied results.     

Determination of Cr(VI) by portable tungsten coil electrothermal atomic absorption spectrometer after surfactant-assisted dispersive liquid-liquid microextraction

As a new developed instrument, a portable tungsten coil electrothermal atomic absorption spectrometer (W-coil ET-AAS) was first coupled with surfactant assisted dispersive liquid–liquid microextraction (SA-DLLME) to improve its analytical performance and expand its applications in this work. SA-DLLME was very simple, rapid and the extraction efficiency was considerably improved by the effect of surfactant, which was suitable to be coupled with the portable instrument in field analysis. After SA-DLLME, concentrated chromium in organic phase was directly determined on W-coil atomiser. The influence factors relevant to SA-DLLME and instrumental conditions were studied systematically. Under the optimal conditions, the limit of detection (LOD) for Cr(VI) was 0.016 µg L^?1, with sensitivity enhancement factor (EF) of 107. The relative standard deviation (RSD) for seven replicate measurements of 0.5 µg L^?1 of Cr(VI) was 4.6%. The recoveries for the spiked samples were in the acceptable range of 96.8–104%. The rapid, simple and high effective method greatly improved the sensitivity of this portable spectrometer for the determination of Cr(VI) and was applied to the analysis of ultra-trace Cr(VI) in real and certified water samples with satisfactory results.     

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%.