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V4 Platform on Flow Analysis and Capillary Electrophoresis

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A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Analytical Chemistry".

Deadline for manuscript submissions: closed (10 October 2021) | Viewed by 23386

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Dr. Michał Woźniakiewicz

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Department of Analytical Chemistry, Faculty of Chemistry, Jagiellonian University, Kraków, Poland
Interests: capillary electrophoresis; forensic chemistry
Special Issues, Collections and Topics in MDPI journals

Dr. Petr Chocholous

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The Department of Analytical Chemistry, Faculty of Pharmacy, Charles University, Ak. Heyrovského 1203, 500 05 Hradec Králové, Czech Republic
Interests: flow analysis; sequential injection chromatography; sample pretreatment; online solid phase extraction; pharmaceutical analysis; bioanalysis

Special Issue Information

Dear Colleagues,

The V4 Symposium “Flow Analysis and Capillary Electrophoresis” (FACE 2020) will be organized at the Faculty of Chemistry of Jagiellonian University in Kraków, Poland, from 28th June to 1st July 2021 and held online.

The goal of FACE 2020, co-financed by International Visegrad Fund, is to establish and strengthen a thematic platform for the collaboration and integration of universities from the Visegrad Group (V4) and other European and overseas countries that conduct research and teaching in analytical chemistry, particularly in the field of flow analysis and capillary electrophoresis. Our institutional project partners are: Faculty of Pharmacy in Hradec Kralove of the Charles University, Institute of Analytical Chemistry of Czech Academy of Sciences in Brno, Faculty of Science and Technology of the University of Debrecen, Research Institute of Biomolecular and Chemical Engineering of the University of Pannonia in Veszprem, Faculty of Natural Sciences of the Comenius University in Bratislava, Faculty of Science of the Pavol Jozef Safarik University in Kosice, and Faculty of Chemistry of the University of Warsaw.

Leading analysts from outside these centers have also announced their participation in our symposium, including researchers from Spain, Portugal, Thailand, and Brazil. In addition to oral and poster presentations as part of the symposium, we plan to organize very interesting workshops covering aspects of flow analysis, capillary electrophoresis, and green analytical chemistry. Numerous distinguished speakers have accepted our invitation, including Bogusław Buszewski, Victor Cerda, Wolfgang Frenzel, Bohuslav Gaš, Peter C. Hauser, Mihkel Kaljurand, Claudimir Lucio do Lago, Duangjai Nacapricha, Edyta Nalewajko-Sieliwoniuk, Ewa Poboży, António O. S. S. Rangel, Marcela Segundo, František Švec, and Elias Zagatto. For further details, please visit the symposium web page: https://v4face.project.uj.edu.pl/.

Participants of the conference are cordially invited to contribute original research papers or reviews to this Special Issue of Molecules.

Dr. Michał Woźniakiewicz
Dr. Petr Chocholous
Guest Editors

This project is co-financed by the Governments of Czechia, Hungary, Poland, and Slovakia through Visegrad Grants from International Visegrad Fund (http://www.visegradfund.org/). The mission of the fund is to advance ideas for sustainable regional cooperation in Central Europe.

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

flow analysis
capillary electrophoresis
microfluidics
microchip electrophoresis
microextraction techniques
open source hardware
biomedical analysis
environmental analysis
forensic analysis
chiral analysis

Published Papers (11 papers)

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11 pages, 6623 KiB

Open AccessArticle

N-Glycosylation Profiling of Human Blood in Type 2 Diabetes by Capillary Electrophoresis: A Preliminary Study

by Rebeka Torok, Klaudia Horompoly, Marton Szigeti, Andras Guttman, Marta Vitai, Laszlo Koranyi and Gabor Jarvas

Molecules 2021, 26(21), 6399; https://doi.org/10.3390/molecules26216399 - 22 Oct 2021

Cited by 3 | Viewed by 2146

Abstract

Currently, diagnosing type 2 diabetes (T2D) is a great challenge. Thus, there is a need to find rapid, simple, and reliable analytical methods that can detect the disease at an early stage. The aim of this work was to shed light on the importance of sample collection options, sample preparation conditions, and the applied capillary electrophoresis bioanalytical technique, for a high-resolution determination of the N-glycan profile in human blood samples of patients with type 2 diabetes (T2D). To achieve the profile information of these complex oligosaccharides, linked by asparagine to hIgG in the blood, the glycoproteins of the samples needed to be cleaved, labelled, and purified with sufficient yield and selectivity. The resulting samples were analyzed by capillary electrophoresis, with laser-induced fluorescence detection. After separation parameter optimization, the capillary electrophoresis technique was implemented for efficient N-glycan profiling of whole blood samples from the diabetic patients. Our results revealed that there were subtle differences between the N-glycan profiles of the diabetic and control samples; in particular, two N-glycan structures were identified as potential glycobiomarkers that could reveal significant changes between the untreated/treated type 2 diabetic and control samples. By analyzing the resulting oligosaccharide profiles, clinically relevant information was obtained, revealing the differences between the untreated and HMG-CoA reductase-inhibitor-treated diabetic patients on changes in the N-glycan profile in the blood. In addition, the information from specific IgG N-glycosylation profiles in T2D could shed light on underlying inflammatory pathophysiological processes and lead to drug targets. Full article

(This article belongs to the Special Issue V4 Platform on Flow Analysis and Capillary Electrophoresis)

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12 pages, 1135 KiB

Open AccessFeature PaperArticle

Design and Functionalization of a µPAD for the Enzymatic Determination of Nitrate in Urine

by Francisca T. S. M. Ferreira, Raquel B. R. Mesquita and António O. S. S. Rangel

Molecules 2021, 26(21), 6355; https://doi.org/10.3390/molecules26216355 - 21 Oct 2021

Cited by 7 | Viewed by 1560

Abstract

In this work, the design of a microfluidic paper-based analytical device (μPAD) for the quantification of nitrate in urine samples was described. Nitrate monitoring is highly relevant due to its association to some diseases and health conditions. The nitrate determination was achieved by combining the selectivity of the nitrate reductase enzymatic reaction with the colorimetric detection of nitrite by the well-known Griess reagent. For the optimization of the nitrate determination μPAD, several variables associated with the design and construction of the device were studied. Furthermore, the interference of the urine matrix was evaluated, and stability studies were performed, under different conditions. The developed μPAD enabled us to obtain a limit of detection of 0.04 mM, a limit of quantification of 0.14 mM and a dynamic concentration range of 0.14–1.0 mM. The designed μPAD proved to be stable for 24 h when stored at room temperature in air or vacuum atmosphere, and 60 days when stored in vacuum at −20 °C. The accuracy of the nitrate μPAD measurements was confirmed by analyzing four certified samples (prepared in synthetic urine) and performing recovery studies using urine samples. Full article

(This article belongs to the Special Issue V4 Platform on Flow Analysis and Capillary Electrophoresis)

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16 pages, 2724 KiB

Open AccessArticle

Smartphone-Assisted Protein to Creatinine Ratio Determination on a Single Paper-Based Analytical Device

by Izabela Lewińska, Karolina Kurdziałek and Łukasz Tymecki

Molecules 2021, 26(20), 6282; https://doi.org/10.3390/molecules26206282 - 17 Oct 2021

Cited by 4 | Viewed by 2727

Abstract

Proteinuria is a condition in which an excessive amount of protein is excreted in urine. It is, among others, an indicator of kidney disease or risk of cardiovascular disease. Rapid and reliable diagnosis and monitoring of proteinuria is of great importance for both patients and their physicians. For that reason, a paper-based sensor for proteinuria diagnosis was designed, optimized, and validated utilizing smartphone-assisted signal acquisition. In the first step, a few commonly employed protein assays were optimized and compared in terms of analytical performance on paper matrix. The tetrabromophenol blue method was selected as the one providing a sufficiently low limit of detection (39 mg·L⁻¹) on the one hand and appropriate long-term stability (up to 3 months) on the other hand. The optimized assay was employed for protein-to-creatinine ratio (PCR) determination on a single paper-based sensor. For both analytes the linear ranges were within the clinically relevant range. The analytical usefulness of the developed sensors was demonstrated by a PCR recovery study in artificial urine. The obtained PCR recoveries were from ca. 80 to 150%. Full article

(This article belongs to the Special Issue V4 Platform on Flow Analysis and Capillary Electrophoresis)

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9 pages, 1212 KiB

Open AccessArticle

An Automated Hydrodynamically Mediated Technique for Preparation of Calibration Solutions via Capillary Electrophoresis System as a Promising Alternative to Manual Pipetting

by Małgorzata Gołąb, Michał Woźniakiewicz, Paweł M. Nowak and Paweł Kościelniak

Molecules 2021, 26(20), 6268; https://doi.org/10.3390/molecules26206268 - 16 Oct 2021

Cited by 2 | Viewed by 1482

Abstract

In this paper, a novel procedure for preparing calibration solutions for capillary electrophoresis (CE)-based quantitative analysis is proposed. Our approach, named the automated hydrodynamically mediated technique (AHMT), uses a capillary and a pressure system to deliver the expected amount of working solution and diluent directly to a sample vial. As a result, calibration solutions are prepared automatically inside the CE instrument, without any or with minimal manual operation. Two different modes were tested: forward and reverse, differing in the direction of hydrodynamic flow. The calibration curves obtained for a model mixture of analytes using AHMT were thorough compared to the standard procedure based on manual pipetting. The results were consistent, though the volume of obtained calibration solutions and the potential risk of random errors were significantly minimized by AHMT. Its effectiveness was further enhanced by the application of SCIEX^® nanoVials, reducing the actual volume of calibration solutions down to 10 μL. Full article

(This article belongs to the Special Issue V4 Platform on Flow Analysis and Capillary Electrophoresis)

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14 pages, 1837 KiB

Open AccessArticle

Development of Microchip Isotachophoresis Coupled with Ion Mobility Spectrometry and Evaluation of Its Potential for the Analysis of Food, Biological and Pharmaceutical Samples

by Jasna Hradski, Marta Ďuriš, Roman Szucs, Ladislav Moravský, Štefan Matejčík and Marián Masár

Molecules 2021, 26(20), 6094; https://doi.org/10.3390/molecules26206094 - 09 Oct 2021

Cited by 2 | Viewed by 1929

Abstract

An online coupling of microchip isotachophoresis (µITP) with ion mobility spectrometry (IMS) using thermal evaporation interface is reported for the first time. This combination integrates preconcentration power of the µITP followed by unambiguous identification of trace compounds in complex samples by IMS. Short-chain carboxylic acids, chosen as model analytes, were first separated by the µITP in a discontinuous electrolyte system at pH 5–6, and subsequently evaporated at 130 °C during their transfer to the IMS analyzer. Various parameters, affecting the transfer of the separated sample components through the evaporation system, were optimized to minimize dispersion and loss of the analytes as well as to improve sensitivity. The following analytical attributes were obtained for carboxylic acids in the standard solutions: 0.1–0.3 mg L⁻¹ detection limits, 0.4–0.9 mg L⁻¹ quantitation limits, linear calibration range from the quantitation limit to 75 mg L⁻¹, 0.2–0.3% RSD of the IMS response and 98–102% accuracy. The analytical potential of the developed µITP-IMS combination was demonstrated on the analysis of various food, pharmaceutical and biological samples, in which the studied acids are naturally present. These include: apple vinegar, wine, fish sauce, saliva and ear drops. In the real samples, 0.3–0.6% RSD of the IMS response and 93–109% accuracy were obtained. Full article

(This article belongs to the Special Issue V4 Platform on Flow Analysis and Capillary Electrophoresis)

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14 pages, 1636 KiB

Open AccessArticle

Development of an In-Line Enzyme Reactor Integrated into a Capillary Electrophoresis System

by Cynthia Nagy, Ruben Szabo and Attila Gaspar

Molecules 2021, 26(19), 5902; https://doi.org/10.3390/molecules26195902 - 29 Sep 2021

Cited by 4 | Viewed by 1848

Abstract

The goal of this paper was to develop an in-line immobilized enzyme reactor (IMER) integrated into a capillary electrophoresis platform. In our research, we created the IMER by adsorbing trypsin onto the inner surface of a capillary in a short section. Enzyme immobilization was possible due to the electrostatic attraction between the oppositely charged fused silica capillary surface and trypsin. The reactor was formed by simply injecting and removing trypsin solution from the capillary inlet (~1–2 cms). We investigated the factors affecting the efficiency of the reactor. The main advantages of the proposed method are the fast, cheap, and easy formation of an IMER with in-line protein digestion capability. Human tear samples were used to test the efficiency of the digestion in the microreactor. Full article

(This article belongs to the Special Issue V4 Platform on Flow Analysis and Capillary Electrophoresis)

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9 pages, 1161 KiB

Open AccessArticle

Sub-Minute Analysis of Lactate from a Single Blood Drop Using Capillary Electrophoresis with Contactless Conductivity Detection in Monitoring of Athlete Performance

by Petr Kubáň, Věra Dosedělová, Kert Martma, Indrek Rannama, Karmen Reinpold and Ruth Shimmo

Molecules 2021, 26(19), 5817; https://doi.org/10.3390/molecules26195817 - 25 Sep 2021

Cited by 5 | Viewed by 2087

Abstract

A simple and fast method for the analysis of lactate from a single drop of blood was developed. The finger-prick whole blood sample (10 µL) was diluted (1:20) with a 7% (w/v) solution of [tris(hydroxymethyl)methylamino] propanesulfonic acid and applied to a blood plasma separation device. The device accommodates a membrane sandwich composed of an asymmetric polysulfone membrane and a supporting textile membrane that allows the collection of blood plasma into a narrow glass capillary in less than 20 s. Separated and simultaneously diluted blood plasma was directly injected into a capillary electrophoresis instrument with a contactless conductivity detector (CE-C⁴D) and analyzed in less than one minute. A separation electrolyte consisted of 10 mmol/L l-histidine, 15 mmol/L dl-glutamic acid, and 30 µmol/L cetyltrimethylammonium bromide. The whole procedure starting from the finger-prick sampling until the CE-C⁴D analysis was finished, took less than 5 min and was suitable for monitoring lactate increase in blood plasma during incremental cycling exercise. The observed lactate increase during the experiments measured by the developed CE-C⁴D method correlated well with the results from a hand-held lactate analyzer (R = 0.9882). The advantage of the developed CE method is the speed, significant savings per analysis, and the possibility to analyze other compounds from blood plasma. Full article

(This article belongs to the Special Issue V4 Platform on Flow Analysis and Capillary Electrophoresis)

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11 pages, 3876 KiB

Open AccessArticle

Multicommutated Flow Analysis System for Determination of Horseradish Peroxidase and Its Inhibitors

by Justyna Głowacka, Kamil Strzelak and Robert Koncki

Molecules 2021, 26(18), 5630; https://doi.org/10.3390/molecules26185630 - 16 Sep 2021

Cited by 2 | Viewed by 1711

Abstract

A fully mechanized multicommutated flow analysis (MCFA) system dedicated to determining horseradish peroxidase (HRP) activity was developed. Detection was conducted using a flow-through optoelectronic detector-constructed of paired LEDs operating according to the paired emitter-detector diode (PEDD) principle. The PEDD-MCFA system is dedicated to monitoring the enzyme-catalyzed oxidation of p-phenylenediamine (pPD) by a hydrogen peroxide. Under optimized conditions, the presented bioanalytical system was characterized by a linear response range (33.47–200 U/L) with a detection limit at 10.54 U/L HRP activity and 1.66 mV·L/U sensitivity, relatively high throughput (12 signals recordings per hour), and acceptable precision (RSD below 6%). Additionally, the utility of the developed PEDD-MCFA system for the determination of HRP inhibitors allowing the detection of selected thiols at micromolar levels, is demonstrated. The practical utility of the flow system was illustrated by the analysis of some dietary supplements containing L-cysteine, N-acetylcysteine, and L-glutathione. Full article

(This article belongs to the Special Issue V4 Platform on Flow Analysis and Capillary Electrophoresis)

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11 pages, 1150 KiB

Open AccessArticle

Sequential Injection Analysis for Automation and Evaluation of Drug Liberation Profiles: Clotrimazole Liberation Monitoring

by Hana Sklenářová, Marek Beran, Lucie Novosvětská, Daniela Šmejkalová and Petr Solich

Molecules 2021, 26(18), 5538; https://doi.org/10.3390/molecules26185538 - 12 Sep 2021

Cited by 2 | Viewed by 1882

Abstract

A fully automated sequential injection system was tested in terms of its application in liberation testing, and capabilities and limitations were discussed for clotrimazole liberation from three semisolid formulations. An evaluation based on kinetic profiles obtained in short and longer sampling intervals and steady-state flux values were applied as traditional methods. The obtained clotrimazole liberation profile was faster in the case of Delcore and slower for Clotrimazol AL and Canesten cream commercial formulations. The steady-state flux values for the tested formulations were 52 µg cm⁻² h⁻¹ for Canesten, 35 µg cm⁻² h⁻¹ for Clotrimazol AL, and 7.2 µg cm⁻² h⁻¹ for Delcore measured in 4 min sampling intervals. A simplified approach for the evaluation of the initial rate based on the gradient between the second and third sampling points was used for the first time and was found to correspond well with the results of the conventional methods. A comparison based on the ratio of the steady-state flux and the initial rate values for Canesten and Clotrimazol AL proved the similarity of the obtained results. The proposed alternative was successfully implemented for the comparison of short-term kinetic profiles. Consequently, a faster and simpler approach for dissolution/liberation testing can be used. Full article

(This article belongs to the Special Issue V4 Platform on Flow Analysis and Capillary Electrophoresis)

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11 pages, 2631 KiB

Open AccessArticle

Modification of Hemodialysis Membranes for Efficient Circulating Tumor Cell Capture for Cancer Therapy

by Gabor Jarvas, Dora Szerenyi, Jozsef Tovari, Laszlo Takacs and Andras Guttman

Molecules 2021, 26(16), 4845; https://doi.org/10.3390/molecules26164845 - 10 Aug 2021

Cited by 7 | Viewed by 2673

Abstract

Background: It is well known that more than 90% of cancer deaths are due to metastases. However, the entire tumorigenesis process is not fully understood, and it is evident that cells spreading from the primary tumor play a key role in initiating the metastatic process. Tumor proliferation and invasion also elevate the concentration of regular and irregular metabolites in the serum, which may alter the normal function of the entire human homeostasis and possibly causes cancer metabolism syndrome, also referred to as cachexia. Methods: We report on the modification of commercially available hemodialysis membranes to selectively capture circulating tumor cells from the blood stream by means of immobilized human anti-EpCAM antibodies on the inner surface of the fibers. All critical steps are described that required in situ addition of the immuno-affinity feature to hemodialyzer cartridges in order to capture EpCAM positive circulating tumor cells, which represents ~80% of cancer cell types. Results: The cell capture efficiency of the suggested technology was demonstrated by spiking HCT116 cancer cells both into buffer solution and whole blood and run through on the modified cartridge. Flow cytometry was used to quantitatively evaluate the cell clearance performance of the approach. Conclusions: The suggested modification has no significant effect on the porous structure of the hemodialysis membranes; it keeps its cytokine removal capability, addressing cachexia simultaneously with CTC removal. Full article

(This article belongs to the Special Issue V4 Platform on Flow Analysis and Capillary Electrophoresis)

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12 pages, 4584 KiB

Open AccessReview

Capillary Electrophoresis as a Monitoring Tool for Flow Composition Determination

by Mihkel Kaljurand, Piret Saar-Reismaa, Merike Vaher, Jelena Gorbatsova and Jekaterina Mazina-Šinkar

Molecules 2021, 26(16), 4918; https://doi.org/10.3390/molecules26164918 - 13 Aug 2021

Cited by 7 | Viewed by 1885

Abstract

Flow analysis is the science of performing quantitative analytical chemistry in flowing streams. Because of its efficiency and speed of analysis, capillary electrophoresis (CE) is a prospective method for the monitoring of a flow composition withdrawn from various processes (e.g., occurring in bioreactors, fermentations, enzymatic assays, and microdialysis samples). However, interfacing CE to a various flow of interest requires further study. In this paper, several ingenious approaches on interfacing flow from various chemical or bioprocesses to a capillary electrophoresis instrument are reviewed. Most of these interfaces can be described as computer-controlled autosamplers. Even though most of the described interfaces waste too many samples, many interesting and important applications of the devices are reported. However, the lack of commercially available devices prevents the wide application of CE for flow analysis. On the contrary, this fact opens up a potential avenue for future research in the field of flow sampling by CE. Full article

(This article belongs to the Special Issue V4 Platform on Flow Analysis and Capillary Electrophoresis)

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