Application Of CE Research Articles

The Impairment of Liver DNA Conformation and Liver Apoptosis of Mice Caused by CeCl3

Cerium (Ce) was shown to cause various toxic effects both in rats and mice; however, the molecular mechanism by which Ce exert theirs toxicity is still understood. In this report, the impairment of liver DNA conformation and liver apoptosis of mice caused by CeCl(3) was studied in vivo using inductively coupled plasma-mass spectrometry, various spectral methods, gel electrophoresis, and transmission electron micrograph. We found that the coefficients of liver to body weight of the mice treated with CeCl(3) were significantly increased. Ce(3+) could be significantly accumulated in the liver, and it insert itself into DNA base pairs and/or bind to DNA nucleotide, and alter the conformation of DNA. Furthermore, the evaluation by gel electrophoresis and transmission electron micrograph showed that higher dose of Ce(3+) could cause DNA cleavage and hepatocyte apoptosis in mice. Therefore, our study aroused the attention of Ce application and exposure effects especially on human liver for long-term and low-dose treatment.

Synthesis and applications of Ce(III)-imprinted polymer based on attapulgite as the sacrificial support material for selective separation of cerium(III) ions

A surface-imprinting technique combined with a sacrificial support process was established to synthesize a novel Ce(III)-imprinted polymer (CIP) in which attapulgite acts as the sacrificial support material. The CIP was compared with attapulgite, non-imprinted polymer (NIP), and with a Ce(III)-imprinted polymer where attapulgite acts as the support material (AIP). Fourier transmission infrared spectrometry, scanning electron microscopy, transmission electron microscopy, simultaneous thermogravimetry, nitrogen sorption, and laser particle sizing were employed, and an imprinting mechanism is suggested. Batch experiments were performed to evaluate adsorption kinetics, selective recognition, adsorption isotherms, desorption and regeneration performances of the CIP. The CIP offers fast adsorption kinetics for Ce3+, and the maximum adsorption capacity is 130 mg g−1, which is larger than that of AIP and attapulgite. The absorption abilities of Ce3+ from aqueous solutions followed the order CIP>AIP>attapulgite>NIP. CIP could be reused four times with only about 16% and 18% loss of adsorption capacity in pure Ce3+ solution and potentially interfering ion solution, respectively. The method was applied to the separation and determination of trace Ce3+ in river sediments. The relative standard deviation of the method is 2.6% (n = 6.0), and the detection limit (3σ) is 57 ng L−1.

Recent developments in instrumentation for capillary electrophoresis and microchip-capillary electrophoresis.

Over the last years, there has been an explosion in the number of developments and applications of CE and microchip-CE. In part, this growth has been the direct consequence of recent developments in instrumentation associated with CE. This review, which is focused on the contributions published in the last 5 years, is intended to complement the articles presented in this special issue dedicated to instrumentation and to provide an overview of the general trends and some of the most remarkable developments published in the areas of high-voltage power supplies, detectors, auxiliary components, and compact systems. It also includes a few examples of alternative uses of and modifications to traditional CE instruments.

CE and CEC of nucleosides and nucleotides in food materials

Dietary nucleosides and nucleotides play an important role in the maintenance of functions of bone marrow hematopoietic cells, intestinal mucosa, and brain. Therefore, analysis of those compounds in food is very important for improving and assuring food quality. This review summarized the application of CE and CEC in the analysis of nucleosides and nucleotides in food. The sample preparation and detection are also discussed.

Capillary electrophoresis for the analysis of contaminants in emerging food safety issues and food traceability

This review presents an overview of the applicability of CE in the analysis of chemical and biological contaminants involved in emerging food safety issues. Additionally, CE-based genetic analyzers' usefulness as a unique tool in food traceability verification systems was presented. First, analytical approaches for the determination of melamine and specific food allergens in different foods were discussed. Second, natural toxin analysis by CE was updated from the last review reported in 2008. Finally, the analysis of prion proteins associated with the "mad cow" crises and the application of CE-based genetic analyzers for meat traceability were summarized.

Cover Picture: Electrophoresis 9'2010

AbstractIssue no. 9 is a special issue on “CEC and EKC” comprising one “Fast Track” article and 21 articles distributed over two distinct parts. “Part I groups 13 contributions on enantioseparations in CE, CEC and capillary LC using various chiral selectors and their applications to a wide range of chiral species, while Part II assembles 8 papers on various methodological aspects and applications of EKC, CEC and CE”. The “Fast Track” paper describes enhanced selectivity in CZE with multi‐chiral selector systems.

Growing trend of CE at the omics level: The frontier of systems biology

In a novel attempt to comprehend the complexity of life, systems biology has recently emerged as a state-of-the-art approach for biological research in contrast to the reductionist approaches that have been used in molecular cell biology since the 1950s. Because a massive amount of information is required in many systems biology studies of life processes, we have increasingly come to depend on techniques that provide high-throughput omics data. CE and CE coupled to MS have served as powerful analytical tools for providing qualitative and quantitative omics data. Recent systems biology studies have focused strongly on the diagnosis and treatment of diseases. The increasing number of clinical research papers on drug discovery and disease therapies reflects this growing interest among scientists. Since such clinical research reflects one of the ultimate purposes of bioscience, these trends will be sustained for a long time. Thus, this review mainly focuses on the application of CE and CE-MS in diagnosis as well as on the latest CE methods developed. Furthermore, we outline the new challenges that arose in 2008 and later in elucidating the system-level functions of the bioconstituents of living organisms.

Recent advances in the application of capillary electromigration methods for food analysis and Foodomics

The use of capillary electromigration methods to analyze foods and food components is reviewed in this work. Papers that were published during the period April 2007 to March 2009 are included following the previous review by García-Cañas and Cifuentes (Electrophoresis, 2008, 29, 294-309). These works include the analysis of amino acids, biogenic amines, peptides, proteins, DNAs, carbohydrates, phenols, polyphenols, pigments, toxins, pesticides, vitamins, additives, small organic and inorganic ions and other compounds found in foods and beverages, as well as those applications of CE for monitoring food interactions and food processing. The use of microchips, CE-MS, chiral-CE as well as other foreseen trends in food analysis are also discussed including their possibilities in the very new field of Foodomics.

Recent advances in the application of CE to forensic sciences: A update over years 2007–2009

This article reviews and comments the applications of CE to forensic sciences covering the short period from 2007 until the first months of 2009, being the latest update of two previous review papers covering the years from 2001 to 2004 and from 2005 to 2007. The overview includes the most relevant examples of analytical applications of capillary electrophoretic and electrokinetic techniques in the following fields: (i) illicit and abused drugs, (ii) small ions of forensic interest (iii) proteins and peptides, (iv) forensic deoxyribonucleic acid, (v) dyes and inks. As many as 69 references are quoted.

High‐performance CE of Escherichia coli K4 cell surface polysaccharides

A high-performance CE application for a quick, reproducible, highly precise and sensitive determination of the lipopolysaccharide produced by Escherichia coli K4 (O5:K4:H4) and of its de-lipid A form is described. The two species were separated within 30 min on an uncoated fused-silica capillary, in normal polarity mode at 20 kV, using an SDS buffer. Detected at 190 nm, the de-lipid A and the LPS species showed two peaks at distinctive migration times (10.45 and 16.10 min, respectively) and were quantified with high reproducibility and linearity (the correlation factors were 0.99 and 0.98, respectively) over the ranges from 60 to 600 ng (1-10 ng/nL) for de-lipid A lipopolysaccharide and from 150 to 600 ng (2.5-10 ng/nL) for the LPS. The described method was also employed in the contemporary analysis and the determination of the two E. coli K4 cell surface polysaccharides, the LPS and the K4, and of their defructosylated and de-lipid A species, respectively. The four molecules were detected and precisely quantified in complex matrices as fermentation broth supernatant or in samples withdrawn throughout the purification process, thus demonstrating the possibility to apply high-performance CE as a reliable analytical tool in biotechnological processes.

Image indexing using spatial texture pattern for CE applications

This paper proposes an image retrieval technique using local texture feature based on Fourier transform. The proposed texture feature not only more effectively represents spatial correlation of texture pattern but also contains less feature vector size over existing ones. In experimental results, the proposed method has shown improved retrieval results over the existing methods.

Antimony(III)- D, L-Tartrates Exhibit Proton-Assisted Enantioselective Binding in Solution and in the Gas Phase

The negative ion mode ESI mass spectral analysis of antimony(III)-D- and -L-tartrate ("tartar emetic"), in association with leucine enantiomeric isotopomers, revealed remarkable proton-assisted enantioselective molecular recognition phenomena. The current study infers that recognition of amino acids by antimony(III)-D,L-tartrate complexes requires that the chiral selector associate a proton to become enantioselective. The dianionic selector itself failed to show enantiomeric discrimination capacity. This observation was shown to be consistent both in solution-phase targeting full scan and gas-phase targeting collision threshold dissociation (CTD) experiments. Importantly, this disparity in enantioselective binding capacity between the dianionic and the protonated monoanionic representatives of antimony(III)-D- and -L-tartrates could only be clearly revealed by ESI-MS and tandem mass spectrometry experiments as described herein. This finding urges a more in-depth study of mechanisms associated with exhibited enantiomeric resolving capacity of antimony tartrates in HPLC and CE applications, as well as in former ESI-MS association studies.

Cover Picture: Electrophoresis 13'09

AbstractIssue 13 is a special issue on “CE and CEC of Amino Acids, Peptides and Proteins” assembling 19 papers on various topics including fast, high efficient and high sensitive “CE and CEC techniques for quality control and purity determination of native and (bio)synthetic amino acids, peptides and proteins, for monitoring of their synthesis, isolation, chemical derivatization and enzymatic digestion and also for investigation of their interactions with other molecules. New methodologies, such as electrodialysis for sample preparation, chiral ligand‐exchange CE, immunoaffinity CE, affinity capillary isoelectric focusing, combination of transient isotachophoretic preconcentration with capillary zone electophoresis (CZE) analysis, two‐dimensional CE‐mass spectrometry (MS) separations and advances in high‐sensitive CE‐laser induced fluorescence (LIF) and CE‐electrochemiluminescence detection schemes, are widely presented here. The applications of CE and CEC methods include chiral analysis of amino acids, determination of low abundant amino acids, peptides and proteins in complex matrices, such as human and animal body fluids and tissue biopsies, and profiling of cell lysates and recombinant proteins, e.g. birch pollen allergen and human interleukin 7. As can be seen from several contributions, preparation of new capillary coatings suppressing the adsorption of peptides and proteins to the fused silica capillary wall in their CZE analyses and/or increasing the selectivity of their open‐tubular CEC separations remains a hot topic in the area of CE and CEC developments. In addition, it is shown that through the theoretical modelling of the CZE determined effective electrophoretic mobilities of proteins, the important parameters, such as charge, hydration and shape of their molecules, can be estimated.”

Capillary electrophoresis of small ions using complex formation and indirect detection

The journal Electrophoresis was launched in about the same time as modern CE. Today, Electrophoresis is one of the leading journals in the field of analytical separations. With over 23% of all papers on CE published in the past 5 years Electrophoresis is also the number one journal covering CE applications. During the past three decades CE has matured into one of the key separation techniques for the analysis of a large variety of ions. Analysis of small organic and inorganic ions used to be a high flyer during the development of CE, often under the name capillary ion analysis. In this mode it was mostly applied for analysis of inorganic ions in waters and/or determination of food ingredients and additives. Complex forming equilibria were commonly used for optimization of the separation and indirect UV absorbance detection was often the only choice for the detection of non-absorbing ions. This short critical overview reflects some of the aspects of CE based on indirect UV absorbance detection and complex forming equilibria related to our work on the topic published in Electrophoresis almost 20 years ago.

Separation of R‐form lipopolysaccharide and lipid A by CE–Fourier‐transform ion cyclotron resonance MS

Lipopolysaccharide (LPS) is the main component of the outer leaflet of the outer membrane of Gram-negative bacteria. Native isolates of LPS comprise a high inherent heterogeneity. This paper presents the first application of CE to separate and online mass analyze the different constituents of underivatized R-form LPS and lipid A with an FT ion cyclotron resonance mass spectrometer. A Beckman P/ACE MDQ and a home-made CE instrument were coupled to the mass spectrometer using a sheath liquid interface. An optimized CE electrolyte based on water, isopropyl alcohol, triethylamine and acetic acid at pH 8.9 allowed the separation of molecular species even of complex mixtures to a large extent with observed detection limits of single constituents of the samples in the low femtomol range. Comparison of CE-MS and MS measurements under equal conditions enabled the investigation of ion suppression effects in LPS samples.

Characterization of the interaction of cefadroxil with different metal ions using CE

The present study describes the application of CE to investigate the interaction between a cephalosporin, cefadroxil and different metal ions. This study aims at quantifying the interaction of cefadroxil with Zn(2+), Al(3+), Fe(3+), Cu(2+) and Co(2+) ions using the effective electrophoretic mobility as a parameter for calculation of the reaction association constant (K). For this purpose, the electrophoretic mobilities of cefadroxil at different metal ion concentrations in citrate buffer pH 3.6 were determined. A mathematical model to calculate the association constant between cefadroxil and metal ions was used. The results showed that a strong change in the cefadroxil electrophoretic mobility was observed by increasing the metal ion concentrations. The results revealed that by increasing the concentration of metal ions in the running buffer the degree of complexation increases too. On the basis of the results, the strength of the interaction of cefadroxil with the investigated metal ions follows the order Zn(2+)>Cu(2+)>Co(2+)>Fe(3+)>Al(3+). The association constant of the investigated reactions ranged from 451.57 to 1546.52 L/mmol. The results indicate that it is possible to characterize the interaction between cefadroxil and metal ions quantitatively using CE.

Covalent modification of fused silica capillaries with quaternized polyamines to achieve robust and stable anodic electroosmotic flow

Synthetic chemistry originally developed for the manufacture of chemically stable silica polyamine composites was adapted for the modification of fused silica capillaries for application in CE. Polyethyleneimine (PEI) and polyallylamine (PAA) were covalently bonded to the interior surface of fused silica capillaries utilizing 3-chloropropyltrichlorosilane (CPTCS) or 3-glycidoxypropyl-trimethoxysilane (GPTMS) to anchor the polymers to the surface. The surface-bound polymers were subsequently quaternized using methyl iodide (MeI). The resulting modified capillaries were studied using CE, and were shown to provide reproducible, stable, and robust anodic EOF throughout the pH range of 2-10. Surface modifications utilizing CPTCS could be rinsed with up to 6 M HCL or 1 M NaOH without significant loss of surface modifier. The utility of the modified capillaries for the separation of simple anions and cations was demonstrated.

The combination of flow injection with electrophoresis using capillaries and chips

The technique of combined flow injection CE (FI-CE) integrates the essential favorable merits of FI and CE. It utilizes the various excellent on-line sample pretreatments and preconcentration (such as cloud point extraction, SPE, ion-exchange, dynamic pH junction and head-column field-amplified sample stacking technique) of FI, which has the advantages of high speed, accuracy, precision and avoiding manual handling of sample and reagents. Therefore, the coupling of FI-CE is an attractive technique; it can significantly expand the application of CE and has achieved many publications since its first appearance. The basic principles, instrumental developments and applications of FI-CE system from 2006 to 2008 are reviewed.

Affinity and Immunoaffinity CE and CEC

Since the late 1980s, there has been increasing interest in the application of affinity isolation procedures as a pre-cleanup procedure prior to capillary electrophoretic separations. The advantage of such an approach was demonstrated in 1992 by the Whitesides group, who coined the abbreviation ACE (affinity capillary electrophoresis). Since that time, a growing number of investigators have applied ACE to study a variety of research problems ranging from drug-ligand interactions to receptor interactions and chemometrics. The marriage of the selectivity of antibodies to capillary electrophoretic separations has added a new dimension to separation sciences. The incorporation of immobilized antibodies has led to the development of specific pre-analysis concentrators by the Guzman group providing specific selection of defined analytes from complex biological matrices prior to analysis. Further, capillary electrophoresis has become a useful platform for performing liquid and solid-phase immunoassays for important markers in basic and clinical research. Capillary electrophoresis itself can be considered a miniaturized technique but it also lends well to the development of chip-based systems, especially the design and development of “labs-on-a-chip”. The 23 papers that comprise this Special Issue are divided into five sections including a series of reviews followed by a selection of papers on the application of affinity CE and CEC. The third section comprises of a series of papers on more specialized applications of ACE and the fourth section deals with immunoaffinity applications. Finally, the fifth section is a collection of chip-based applications. Although this is the first Special Issue devoted to Affinity and Immunoaffinity CE and CEC, I feel sure that others will follow as these techniques become more widely used and popular. “…capillary electrophoresis has become a useful platform for performing liquid and solid-phase immunoassays for important markers in basic and clinical research.” As editor of this Special Issue, I would like to express my sincere thanks to all of the authors for their valuable contributions, the referees for their valuable time and expertise in evaluating these manuscripts and especially to Professor El Rassi, the Editor-in-Chief of ELECTROPHORESIS, for his continuous support during the preparation of this issue. Terry M. Phillips Guest Editor

Cover Picture: Electrophoresis 16/2008

AbstractIssue no. 16 is a Special Issue on “Affinity and Immunoaffinity CE and CEC” consisting of 23 papers that are arranged into five parts. The first part has 4 review articles followed by a selection of 5 papers in the second part on the application of affinity CE and CEC assembled . The third part comprises a series of papers on more specialized applications of ACE and the fourth part deals with immunoaffinity applications. Finally, the fifth part is a collection of chip‐based applications.