Applications of capillary electrophoresis with electrochemical detection in pharmaceutical and biomedical analyses

As a high efficiency separation technique, capillary electrophoresis has been widely used in various fields of analytical science. This review discusses the applications of electrochemical detection systems combined with capillary electrophoresis in pharmaceutical and biomedical analysis. These detection methods mainly involve amperometric detection but also include conductivity detection and potentiometric detection. Its applications in the field are divided into six parts, including catechol compounds, thiols, amino acids and peptides, carbohydrates, general pharmaceuticals, and other related compounds. A relatively detailed discussion is described for each compound under the current studied. On this basis, we have suggested several conceivable directions for capillary electrophoresis with electrochemical detection in the future.     

LC with Electrochemical Detection. Recent Application to Pharmaceuticals and Biological Fluids

Many pharmaceutical compounds have electroactive groups and are readily measurable and detectable by liquid chromatography with electrochemical detection (LC–EC). LC–EC techniques have many advantages as measurement systems and new materials have been developed for working electrodes. Use of modern electroanalytical techniques for detection in LC of pharmaceutical compounds is discussed in this review. EC detection in LC often results in improved selectivity and detection limits for electroactive pharmaceutical compounds. Selected literature on the determination of pharmaceutical compounds in their dosage forms and in biological samples are reported.     

Design and use of electrochemical sensors in enantioselective high throughput screening of drugs. A minireview

The importance of reliable detection systems for enantiomeric assays increases with the necessity of high throughput screening analysis of raw materials for the pharmaceutical industry. The utilization of electrochemical sensors in enantioselective analysis is an accurate and precise alternative to chromatographic techniques. The reliability of the response characteristics as well as of the analytical information obtained by using electrochemical sensors is strictly correlated with the design of the sensors. The designs evaluated for sensors have been based on PVC, imprinting polymers and carbon paste matrices. Among these, carbon paste sensors have been the most reliable and have been utilized for the construction of potentiometric, enantioselective membrane electrodes as well as for amperometric biosensors, and immunosensors. There are two ways to use the electrochemical sensors in enantioselective screening analysis: selective binding and catalyst selectivity. A molecule with a special chemical architecture is required for selective binding: a lock for a key. The high reliability of analytical information obtained using these sensors has made possible the automation of potentiometric and amperometric techniques by integration of enantioselective sensors as detectors in flow injection analysis and sequential injection analysis techniques.     

Chemiluminescence detection in HPLC and CE for pharmaceutical and biomedical analysis

The present paper reviews the developments and applications of chemiluminescence detection with HPLC and CE in pharmaceutical and biomedical analysis. The chemiluminescence systems, chemiluminogenic reagents and derivatization reagents, improvements in instrumental design as well as their contributions to the practical applications, are all presented. The advantages and limitations of current detection methodology and future prospects for improvement are briefly discussed.     

Application of capillary electrophoresis with capacitively coupled contactless conductivity detection (CE‐C4D): An update

Capacitively coupled contactless conductivity detection (C⁴D) has appeared as a powerful technique for the detection of compounds lacking chromogenic or fluorogenic group. Since our last review (Biomedical Chromatography 2014; 28 : 1502–1506) several new capillary electrophoresis (CE)‐C⁴D methods have been reported. This review provides an update of the most recent utilization of CE‐C⁴D in the field of pharmaceutical, biomedical and food analysis covering the period from February 2014 to October 2016. The use of CE with C⁴D in the pharmaceutical field has been shown in many papers. Examples illustrate the applicability of CE‐C⁴D in the fields of pharmaceutical, biomedical and food analysis. Finally, general conclusions and perspectives are provided.     

Voltammetric determination of sinomenine in biological fluid using a glassy carbon electrode modified by a composite film of polycysteic acid and carbon nanotubes

Polycysteic acid based electrochemical oxidation of L-cysteine (CySH) and carbon nanotubes (CNTs) formed a composite thin film material at a glassy carbon electrode (GCE) that was used a novel modifier for electroanalytical determination of sinomenine which is used for rheumatoid arthritis treatment. The determination of sinomenine at the composite modified electrode was studied by differential pulse voltammetry (DPV). The peak current obtained at + 0.632 V (vs SCE) from DPV was linearly dependent on the sinomenine concentration in the range of 1.0 x 10(-7) to 6.0 x 10(-5) M in a B-R buffer solution (0.04 M, pH 1.81) with a correlation coefficient of 0.998. The detection limit (S/N = 3) was 5.0 x 10(-8) M. The electrochemical reaction mechanism of sinomenine was also discussed. This new method was then applied to the high-throughput determination of sinomenine in human serum samples with satisfactory results. This polycysteic acid/CNTs composite film may be considered to be a promising, low-cost, durable, and biocompatible material for the modification of sensors in applications to pharmaceutical and biomedical analysis.     

Sensitivity enhancement in capillary electrophoresis and their applications for analyses of pharmaceutical and related biochemical substances

This review aims to illustrate sensitivity enhancement methods in capillary electrophoresis (CE) and their applications for pharmaceutical and related biochemical substance analyses. The first two parts of the article describe the introduction and principle of CE. The main part focuses on strategies for sensitivity improvement in CE including detector and capillary technologies and preconcentration techniques. Applications of these techniques for pharmaceutical and biomedical substance analyses are surveyed during the years 2018–2021.     

Carbon nanotube-chitosan modified disposable pencil graphite electrode for vitamin B12 analysis

A single walled carbon nanotube-chitosan (SWCNT-chitosan) modified disposable pencil graphite electrode (PGE) was used in this study for the electrochemical detection of Vitamin B(12). Electrochemical behaviors of SWCNT-chitosan PGE and chitosan modified PGE were compared by using cyclic voltammetry (CV), square-wave voltammetry (SWV) and electrochemical impedance spectroscopy (EIS) techniques. SWCNT-chitosan modified electrode was also used for the quantification of Vitamin B(12) in pharmaceutical products. The results show that this electrode system is suitable for sensitive Vitamin B(12) analysis giving good recovery results. The surface morphologies of the SWCNT-chitosan PGE, chitosan modified PGE and unmodified PGE were characterized by using scanning electron microscopy (SEM).     

液相色谱-化学发光检测法的最新进展

评述了近年来液相色谱－化学发光检测法的最新进展,参考文献从１９９２年到１９９５年。内容涉及各类化学发光反应同液相色谱体系的耦合方式,仪器设计,多种无机、有机、生物大分子、生物活性物质及药物的分析方法及其在环境、生物医学科学和生命科学、临床化学及药物化学中的应用和发展方向。     

Electrochemical analysis of organic compounds in solid-state: applications of voltammetry of immobilized microparticles in bioanalysis and cultural heritage science

Most of the advances in the electrochemical study of solid materials are due to the development and application of voltammetry of immobilized microparticles in several areas besides electroanalytical. The technique has been applied in the evaluation of solid-state electrochemical behavior of compounds, qualitative and semi-quantitative determinations, monitoring of products derived from specific reactions, authentication and discrimination of several samples, and as quality control analytical tool. Recently, the studies involving solid organic compounds in different areas, such as pharmaceutical, biomedical, food, and cultural heritage sciences, have emerged and deserved special attention. In this regard, this paper aims to review the state-of-the-art of voltammetry of immobilized microparticles applied to organic compound analysis in solid-state in several research fields, highlighting some technique features and their applications for different purposes.

     

电化学免疫分析法研究进展

电化学免疫分析法是将免疫分析与电化学分析技术相结合的一种免疫分析新方法，近十多年来，电化免疫分析的研究有了迅速的发展。本文对电化学的免疫分析法的标记物、免疫方法、电化学检测技术进行了概括总结，并展望了电化学免疫分析的发展前景。     

Application of molecularly imprinted polymers for electrochemical detection of some important biomedical markers and pathogens

The determination of biomedical markers and pathogens using electrochemical sensors is a well-established technique in which the transducer and the recognition element are used to detect the target molecule. There is a growing interest in molecularly imprinted polymer (MIPs) applications as promising recognition elements. The use of MIPs as recognition elements in electrochemical sensors offers the advantages of being fast, low cost, and, at the same time, provides accurate and selective results compared with other commonly applied routine methods for biomedical markers and pathogen detection. Compared with other nanomaterials and aptamer-based biosensors, MIP-based sensors offered excellent selectivity for low-priced reagents to be used. The aim of the current review is to discuss the most recent applications of MIP-based electrochemical sensors (2019–2021) as promising detection devices for some important biomarkers, enzymes, and pathogens, such as viruses, bacteria, and toxins.     

Versatile Metalloporphyrin-Based Electrochemical Sensing Applications: From Small Gasotransmitters to Macromolecules

At the beginning of his youthful sixth decade, this work is dedicated to Prof. Dr. Fabio Doctorovich. He is distinctive in organometallic chemistry. During his successful career, he has been studying the reactivity and application of metalloporphyrins. Metalloporphyrins are organometallic complexes that exhibit, through synthetic modifications, the ability to tune their optical and electrochemical properties and their selectivity towards a particular molecule or ion. For this reason, they are systems extremely useful as electrochemical sensors to detect and quantify a wide variety of analytes with high selectivity, even in real samples such as food, water, biological fluids, or pharmaceutical compounds. This review presents an up-to-date list of reports in which metalloporphyrins are used as electrochemical sensors. In addition to compiling a comprehensive and up-to-date list of reported sensors that utilize metalloporphyrins, this work aims to provide an overview of currently available tools and techniques for the detection of various chemical species through similar approaches, which are constantly being developed.     

Multimodal electrochemical and nanoplasmonic biosensors using ferrocene-crowned nanoparticles for kinase drug discovery applications

The use of on-chip multimodal sensing approaches is very promising towards integrated biosensing systems, which measure different parameters involved in biomolecular interactions and provide automated validation of true positives. In this report, we investigate a proof of concept that enables multiple detection technologies for screening inhibitors of kinase activity, which is a crucial process in drug discovery applications. We demonstrate the integration of electrochemical techniques on the same chip, namely, differential pulse voltammetry, impedance spectroscopy, and direct open circuit potential measurements. Gold nanoparticles that attach to the thio-phosphorylated proteins facilitate localised surface plasmon resonance detection. The addition of thiolated ferrocene, which attaches to the nanoparticles like a crown, enables sensitive electrochemical amperometric detection of kinase activity. This novel multimodal biosensor provides a more rigorous measurement of biomolecules, with wide significance in biomedical, environmental, and pharmaceutical applications.     

Cloud point extraction as a sample enrichment technique for capillary electrophoresis–An overview

Abstract

Cloud point extraction (CPE) is a simple, inexpensive and green sample enrichment technique for different analytes in different matrices. In this technique surfactant solution is used at concentration above critical micelle concentration to extract the analytes from various matrices. Capillary electrophoresis (CE) and family of related techniques have emerged as powerful analytical techniques for pharmaceutical, biomedical, food and environmental analysis. In this review we have described the applications of CPE coupling with CE.     

Ratiometric electrochemical,electrochemiluminescent, and photoelectrochemical strategies for environmental contaminant detection

Global environmental pollution issue has boosted the development of novel analytical techniques with high efficiency and accuracy for detection of hazardous contaminants. Strategies based on electrochemical, electrochemiluminescent, or photoelectrochemical analysis are among the promising detection approaches to provide rapid and sensitive analysis. Currently, combining ratiometric assay with such strategies can further promote their sensing reliability and reproducibility in complex conditions. This review highlights recent advances of ratiometric electrochemical, electrochemiluminescent, and photoelectrochemical sensors in the past 2 years. Their signal generation strategies and analysis applications, particularly for the environmental contaminant detection, are discussed in detail, and a future prospect in this area from us is also provided.     

The electrochemical oxidation of troxerutin and its sensitive determination in pharmaceutical dosage forms at PVP modified carbon paste electrode

The voltammetric responses of troxerutin were investigated at polyvinylpyrrolidone (cross-linked) (PVP) modified carbon paste electrode (CPE) in 0.1 mol/L KCl by several electrochemical techniques. A well-defined oxidation peak was observed at about 0.97 V. Compared with poor responses of troxerutin at bare electrode that at this modified electrode has been greatly improved. It is PVP that enhances the adsorption of troxerutin to electrode surface based on their hydrophobic property. Under some optimized experimental conditions, a simple and sensitive electroanalytical method was developed for the quantitative analysis of troxerutin. A very low detection limit of 5.0 x 10(-9)mol/L was obtained for 5 min accumulation at open circuit (S/N=3). This proposed method was successfully applied to the detection of troxerutin in pharmaceutical dosage forms and satisfying results had been obtained.     

Robots in flexible analysis systems

In this article an attempt is made to place robots in the general context of automation. The changes that will have to take place to avoid the robot becoming a dedicated instrument are discussed. To obtain real flexible analysis systems both hardware and software will have to change. The robot periphery and the controllers will have to be standardised, and to become more user-friendly the software developments based on the techniques of artificial intelligence (AI) will have to be supported by appropriate tactile and visual sensors. Experience based on the automation of sample preparation in biomedical and pharmaceutical analysis with existing laboratory equipment is discussed in this perspective.     

Zero‐valent Iron Nanoparticles Modified Screen‐printed Electrode for FIA or HPLC Amperometric Detection of Metronidazole in Pharmaceutical Formulations

A zero‐valent iron nanoparticles modified electrode was employed as an amperometric detector in flow conditions to determine metronidazole and 2‐methyl‐5‐nitroimidazole in pharmaceutical formulations. Flow injection analysis at ?0.6 V (vs. Ag) achieved limits of detection of 2 and 6 μM for metronidazole and 2‐methyl‐5‐nitroimidazole, respectively, but the analysis was not discriminative between the two compounds. When reverse phase high performance liquid chromatography was applied previous to the electrochemical detection both analytes could be analysed simultaneously. However, the limits of detection slightly increased (10 μM) as a consequence of the use of an organic solvent and a lower sample volume. The relative standard deviation of analytical repeatability was <4.0 % in both techniques. The methods were validated by comparing the results obtained from the analysis of commercial samples with those provided by HPLC‐DAD and no significant differences were detected. Results probed that the modified electrode was a successful tool in the FIA and HPLC analysis of nitro compounds.     

毛细管电泳安培型电化学检测法

本文评述了近年来安培型电化学检测法在毛细管电泳中的发展概况，归纳了二种检测方式及其装置的结构特点。阐述了金属电极、液膜电极和修饰电极等在电化学检测应用研究中的作用以及此方法在微区分析、活体分析中的重要意义，并展望了其发展前景。