Chromatographic Techniques for Rare Earth Elements Analysis

2017 ◽  
Vol 2 (4) ◽  
Author(s):  
Beibei Chen ◽  
Man He ◽  
Huashan Zhang ◽  
Zucheng Jiang ◽  
Bin Hu
Keyword(s):  
Rare Earth ◽  
Separation Efficiency ◽  
Stationary Phases ◽  
Exchange Chromatography ◽  
Chromatographic Techniques ◽  
Mobile Phases ◽  
Very High ◽  
High Separation ◽  
Separation Of Rees

AbstractThe present capability of rare earth element (REE) analysis has been achieved by the development of two instrumental techniques. The efficiency of spectroscopic methods was extraordinarily improved for the detection and determination of REE traces in various materials. On the other hand, the determination of REEs very often depends on the preconcentration and separation of REEs, and chromatographic techniques are very powerful tools for the separation of REEs. By coupling with sensitive detectors, many ambitious analytical tasks can be fulfilled.Liquid chromatography is the most widely used technique. Different combinations of stationary phases and mobile phases could be used in ion exchange chromatography, ion chromatography, ion-pair reverse-phase chromatography and some other techniques. The application of gas chromatography is limited because only volatile compounds of REEs can be separated. Thin-layer and paper chromatography are techniques that cannot be directly coupled with suitable detectors, which limit their applications. For special demands, separations can be performed by capillary electrophoresis, which has very high separation efficiency.

scholarly journals A Comparative Study of Advanced Stationary Phases for Fast Liquid Chromatography Separation of Synthetic Food Colorants

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3335
Author(s):  
Ivona Lhotská ◽  
Petr Solich ◽  
Dalibor Šatínský
Keyword(s):  
Separation Efficiency ◽  
Water Solution ◽  
Stationary Phases ◽  
Gradient Elution ◽  
Synthetic Food Colorants ◽  
Liquid Chromatography Separation ◽  
Method Optimization ◽  
Superficially Porous Particles ◽  
Fast Liquid Chromatography

Food analysis demands fast methods for routine control and high throughput of samples. Chromatographic separation enables simultaneous determination of numerous compounds in complex matrices, several approaches increasing separation efficiency and speed of analysis were involved. In this work, modern types of column with monolithic rod or superficially porous particles were employed and compared for determination of eight synthetic food dyes, their chromatographic performance was evaluated. During method optimization, cyano stationary phase Chromolith Performance CN 100 × 4.6 mm and Ascentis Express ES-CN 100 × 4.6 mm, 5 µm were selected for the separation of polar colorants. The separation was performed by gradient elution of acetonitrile/methanol and 2% water solution of ammonium acetate at flow rate 2.0 mL min−1. Mobile phase composition and the gradients were optimized in order to enable efficient separation on both columns. The method using fused-core particle column provided higher separation efficiency, narrow peaks of analytes resulted in increased peak capacity and shortening of analysis time. After the validation, the method was applied for analysis of coloured beers, soft drinks and candies.

Determination of Nitrophenol Isomers in Water

2015 ◽  
Vol 1083 ◽  
pp. 80-83
Author(s):  
Xiao Na Ji ◽  
Sheng Shu Ai ◽  
Juan Tang ◽  
Hong Qu ◽  
De Jun Bian
Keyword(s):  
Separation Efficiency ◽  
Tap Water ◽  
Target Object ◽  
Hplc Method ◽  
The Other ◽  
Municipal Sewage ◽  
External Standard Method ◽  
External Standard ◽  
High Separation

This paper establishes the HPLC method of determining three nitrophenol isomers in municipal sewage, surface water and tap water. After the sample is filtered and distilled, conduct the monitoring analysis on the distillate with HPLC-DAD and quantify it in external standard method. In the municipal sewage treated in bioanalysis method one type of target object o-nitrophenol is found, whose content is 0.11mg·L-1, no target object is found in all the other samples. This method has the adventages of high separation efficiency and high analysis rate. The experiment result shows that the linear correlation coefficient is above 0.983, the recovery rate lies between 78.6% and 105.2%, the minimum detection limit is 0.05mg·L-1(S/N=3.0).

Gas Liquid Vane Separators in High Pressure Applications

2010 ◽  
Author(s):  
Dani Fadda ◽  
David Barker
Keyword(s):  
Separation Efficiency ◽  
Pressure Vessels ◽  
Cfd Modeling ◽  
Test Results ◽  
Capacity Curves ◽  
Liquid Handling ◽  
Wide Range ◽  
Computational Fluid Dynamics Cfd ◽  
Very High ◽  
High Separation

Vane separators are inertial devices used to remove entrained liquids from gas. They are utilized in pressure vessels operating at a wide range of temperatures and pressures. Computational Fluid Dynamics (CFD) modeling and sizing calculations are used to evaluate the loading to a vane separator and determine the maximum overall gas and liquid handling capacity of the pressure vessel. Test results, performed at operating pressures up to 133 bar (1931 psia) using live natural gas illustrate that, when sized correctly based on the vane’s capacity curves and CFD modeling, vane separators continue to have high separation efficiency at very high operating pressures.

Simultaneous determination of whitening agents and parabens in cosmetic products by capillary electrophoresis with on-line sweeping enhancement

2014 ◽  
Vol 6 (19) ◽  
pp. 7615-7620 ◽  
Author(s):  
I-Chi Tsai ◽  
Chia-Yu Su ◽  
Cho-Chun Hu ◽  
Tai-Chia Chiu
Keyword(s):  
Capillary Electrophoresis ◽  
Simultaneous Determination ◽  
Separation Efficiency ◽  
Analysis Time ◽  
Cosmetic Products ◽  
Short Analysis Time ◽  
On Line ◽  
High Separation

An on-line sweeping-MEKC method for simultaneous determination of whitening agents and parabens in commercial cosmetic products was demonstrated. This approach was shown to offer high separation efficiency, short analysis time, and convenience of analysis. The LODs of the analytes were in the range from 8 to 162 nM (1.1 to 21.0 ng mL−1) and a 46 to 279-fold enhancement was achieved.

scholarly journals Silica gel functionalized with imidazolium group via click chemistry – new stationary phase for ion chromatography

2021 ◽  
Vol 8 (4) ◽  
pp. 20218409
Author(s):  
D. A. Chuprynina ◽  
I. A. Lupanova ◽  
V. V. Konshin ◽  
D. N. Konshina
Keyword(s):  
Ion Exchange ◽  
Stationary Phase ◽  
Silica Gel ◽  
Separation Efficiency ◽  
Click Reaction ◽  
Exchange Chromatography ◽  
Retention Factors ◽  
Exchange Material ◽  
Ph Range

This manuscript describes the preparation of a simple effective ion-exchange material based on silica gel, on the surface of which methylimidazolium bromide is fixed using a click reaction. The resulting material was used as a stationary phase for the separation and determination of Cl–, NO2–, NO3–, I–, and SO42– using ion exchange chromatography. The separation efficiency and retention factors for the selected anions were studied in the pH range 3.5–6.5. The proposed material was used for the determination of Cl–, SO42– in water and can be suggested for successful use in real water samples.

scholarly journals Silica Monolithic Capillary Columns for Hilic Separations

2018 ◽  
Vol 46 (1) ◽  
pp. 39-42
Author(s):  
Dana Moravcová ◽  
Josef Planeta
Keyword(s):  
Stationary Phase ◽  
Separation Efficiency ◽  
Stationary Phases ◽  
Ammonium Hydroxide ◽  
Capillary Columns ◽  
Optimal Separation ◽  
Monolithic Capillary Columns ◽  
High Separation ◽  
Theoretical Plates ◽  
Separation Conditions

Abstract The monolithic capillary columns (0.1 mm x 150 mm) prepared by the acidic hydrolysis of tetramethoxysilane (TMOS) in the presence of polyethylene glycol (PEG) and urea were modified by zwitterionic stationary phases and evaluated under HILIC separation conditions by employing a mixture containing nucleosides and nucleotides. The polymeric layer of zwitterions did not affect the high separation efficiency of the original silica monolith. The prepared zwitterionic columns exhibited high separation efficiencies in a range 61,000-289,000 theoretical plates/m for a 2- methacryloyloxyethyl phosphorylcholine-based stationary phase and in a range 59,000-135,000 theoretical plates/m for a [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide-based stationary phase under optimal separation conditions. The grafted layer of zwitterions on the silica monolithic surface also significantly improved the separation selectivity to compounds of interest

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