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Ioannou KA, Ioannou GD, Christou A, Stavrou IJ, Schmid MG, Kapnissi-Christodoulou CP. Stereoselective separation of psychoactive substances: Multivariate optimization and validation of a capillary electrophoresis method using carboxymethyl-β-CD/deep eutectic solvent dual system. J Pharm Biomed Anal 2024; 239:115897. [PMID: 38071765 DOI: 10.1016/j.jpba.2023.115897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 11/27/2023] [Accepted: 11/30/2023] [Indexed: 01/05/2024]
Abstract
A comprehensive study was performed to determine an optimum enantioseparation method for fluorine-substituted amphetamine and cathinone derivatives (fluor-amphetamine and fluor-cathinone derivatives), using a binary system consisting of carboxymethyl-β-CD (CM-β-CD) and a deep eutectic solvent (DES), namely choline chloride-ethylene glycol (ChCl-EG). Under this framework, the optimization and modeling of the separation conditions in a binary system were performed with the objective of maximizing resolution and minimizing analysis time. This was achieved through the application of response surface methodology. In particular, the effect of chiral selector concentration and percentage of DES on resolution and analysis time were investigated and optimized using a complete experimental design. The optimum enantioseparation conditions were determined to be 13.84 mM CM-β-CD and 0.15% v/v ChCl-EG for fluorine-substituted amphetamine derivatives and 14.36 mM and 0.75% v/v ChCl-EG for fluorine-substituted cathinone derivatives, respectively. This combination resulted in a baseline separation for eight out of the nine analytes studied. Overall, the results demonstrated the synergistic effect of the CM-β-CD/DES dual system and highlighted the significance of DESs as additives in capillary electrophoresis.
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Affiliation(s)
| | | | | | - Ioannis J Stavrou
- Department of Life Sciences, European University Cyprus, 2404 Nicosia, Cyprus
| | - Martin G Schmid
- Department of Pharmaceutical Chemistry, Institute of Pharmaceutical Sciences, University of Graz, 8010 Graz, Austria
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2
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Ioannou GD, Ioannou KA, Christou A, Stavrou IJ, Kapnissi-Christodoulou CP. The Utilization of an Aloe Vera Rind By-Product: Deep Eutectic Solvents as Eco-Friendly and Recyclable Extraction Media of Polyphenolic Compounds. Antioxidants (Basel) 2024; 13:162. [PMID: 38397760 PMCID: PMC10886410 DOI: 10.3390/antiox13020162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 01/22/2024] [Accepted: 01/22/2024] [Indexed: 02/25/2024] Open
Abstract
In this study, an optimized environmentally friendly procedure was employed to enhance the sustainable utilization of phenolic antioxidants derived from aloe vera rind by-products. The procedure involved the application of ultrasound-assisted extraction (UAE) in combination with deep eutectic solvents (DESs). Eleven different DESs and three conventional solvents were employed as extraction media for polyphenolic compounds. Choline chloride-citric acid (ChCl-CA) was selected as the most suitable extractant, considering its extraction efficiency in relation to the total phenolic content. The operating conditions of UAE were optimized and modeled by the use of response surface methodology in order to maximize the yield of total phenolics and antioxidant capacity. The optimal operational parameters for the UAE procedure were determined to be 16.5 min, 74% (v/v) DES in water, and a solvent-to-solid ratio equal to 192. HPLC analysis, which was performed on the optimum extract, revealed significant levels of phenolics present in the aloe rind. Efficient recovery of the extracted antioxidants was obtained by the use of solid-phase extraction (SPE) and polyamide cartridges. The ChCl-CA DES exhibited excellent recycling capability with a yield of over 90% through SPE. Finally, the greenness of the method was evaluated using the green AGREE and AGREEprep metrics. The results highlighted the sustainability and the greenness of the proposed extraction procedure for the aloe by-product.
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Affiliation(s)
- Georgia D. Ioannou
- Department of Chemistry, University of Cyprus, 1678 Nicosia, Cyprus; (G.D.I.); (K.A.I.); (A.C.)
| | - Katerina A. Ioannou
- Department of Chemistry, University of Cyprus, 1678 Nicosia, Cyprus; (G.D.I.); (K.A.I.); (A.C.)
| | - Atalanti Christou
- Department of Chemistry, University of Cyprus, 1678 Nicosia, Cyprus; (G.D.I.); (K.A.I.); (A.C.)
| | - Ioannis J. Stavrou
- Department of Life Sciences, European University Cyprus, 2404 Nicosia, Cyprus;
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Ioannou KA, Ioannou GD, Christou A, Schmid MG, Stavrou IJ, Kapnissi-Christodoulou CP. Novel supramolecular deep eutectic solvent (SUPRADES) as a sole chiral selector in capillary electrophoresis for the enantiomeric separation of fluorine-substituted amphetamine analogs. J Chromatogr A 2024; 1715:464628. [PMID: 38183783 DOI: 10.1016/j.chroma.2024.464628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 12/20/2023] [Accepted: 01/02/2024] [Indexed: 01/08/2024]
Abstract
In this study, a novel supramolecular deep eutectic solvent consisting of sulfated-β-CD and citric acid (S-β-CD-CA) is reported for the first time. This innovative system was evaluated as a sole chiral selector in capillary electrophoresis for the enantioseparation of six fluorine-substituted amphetamine analogs, yielding remarkable outcomes. Baseline separations of all amphetamine analogs under study were achieved in less than 21.00 min using the S-β-CD-CA as the chiral selector. It was observed that the addition of 0.050 % v/v S-β-CD-CA into the background electrolyte resulted in the baseline separation of five out of the six fluorine-substituted amphetamine analogs, while in the case of the para-substituted amphetamine analog, 4-fluoramphetamine (4-FA), a higher percentage (0.15 % v/v) was required to achieve baseline enantioseparation. These findings emphasized the potential of this new supramolecular system in providing a class of solvents with promising chiral recognition properties.
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Affiliation(s)
| | | | | | - Martin G Schmid
- Department of Pharmaceutical Chemistry, Institute of Pharmaceutical Sciences, University of Graz, Graz 8010, Austria
| | - Ioannis J Stavrou
- Department of Life Sciences, European University Cyprus, Nicosia 2404, Cyprus.
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Ioannou KA, Ioannou GD, Christou A, Stavrou IJ, Schmid MG, Kapnissi-Christodoulou CP. The potential of the use of deep eutectic solvents and amino acid-based ionic liquids to enhance the chiral discrimination ability of different chiral selectors in capillary electrophoresis. J Chromatogr A 2023; 1705:464152. [PMID: 37327715 DOI: 10.1016/j.chroma.2023.464152] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 06/08/2023] [Accepted: 06/11/2023] [Indexed: 06/18/2023]
Abstract
The effect of the combined use of amino acid-based ionic liquids (AAILs) and deep eutectic solvents (DESs) with either cyclodextrin- (CD) or cyclofructan- (CF) based chiral selectors for the chiral separation of amphetamine derivatives was investigated in the present study. A non-significant improvement in enantiomeric separation of target analytes was observed when AAILs were combined with either CF or CD. On the other side, a markedly improved chiral separation of enantiomers was obtained using the dual carboxymethyl-β-cyclodextrin/DES system, highlighting the existence of a synergistic effect. After the addition of 0.5% v/v of choline chloride-ethylene glycol, the resolution of the enantiomers of amphetamine, methamphetamine and 3-fluorethamphetamine, increased from 1.4, 1.1, 1.0 to 1.8, 1.8, and 1.5 min, and the analysis times increased from 19.54, 20.48, 18.71 to 35.71, 35.78 and 32.90 min, respectively. This was not the case for the CF/DES dual system, in which the separation of amphetamines worsened, indicating an antagonistic effect. In conclusion, DESs are a very promising additive in capillary electrophoresis that can improve the separation of chiral molecules in combination with CDs but not CFs.
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Affiliation(s)
| | | | | | - Ioannis J Stavrou
- Department of Life Sciences, European University Cyprus, 2404 Nicosia, Cyprus
| | - Martin G Schmid
- Department of Pharmaceutical Chemistry, Institute of Pharmaceutical Sciences, University of Graz, 8010 Graz, Austria
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Christodoulou MC, Constantinou MS, Louppis AP, Christou A, Stavrou IJ, Kapnissi-Christodoulou CP. Determination of cannabinoids in human cerumen samples by use of UPLC-MS/MS as a potential biomarker for drug use. J Pharm Biomed Anal 2023; 231:115412. [PMID: 37087774 DOI: 10.1016/j.jpba.2023.115412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 04/19/2023] [Accepted: 04/19/2023] [Indexed: 04/25/2023]
Abstract
A quantitative analytical procedure was developed and validated by the use of Ultra- Performance Liquid Chromatography tandem Mass Spectrometry (UPLC-MS/MS) for the determination of Cannabidiol (CBD), Cannabinol (CBN), Δ9-Tetrahydrocannabinol (Δ9-THC), Cannabichromene (CBC), Cannabigerol (CBG) and 11-Nor- 9- Carboxy- Tetrahydrocannabinol (THC-COOH) in an unconventional biological matrix, cerumen. All the investigated calibration curves were characterized by high correlation values (R2 ≥ 0.9965). The LODs and LOQs ranged from 0.004 to 0.009 μg g-1 and 0.012-0.029 μg g-1, respectively. Intra-assay and inter-assay precision were found to be 0.6-2.5%, and 0.8-2.2%, respectively. All recovery values of cannabinoids, with the use of the optimum cotton swab, at low (0.008 μg g-1 of cerumen), medium (0.037 μg g-1of cerumen) and high (0.16 μg g-1 of cerumen) control levels, were estimated to be above 86%. The method developed here permitted the analysis of real cerumen samples obtained from fourteen cannabis users. In twelve out of fourteen cases, Δ9-THC was found to be positive, while in six cases, three major cannabinoids, CBN, CBG and Δ9-THC were quantified at concentrations 0.02-0.21 μg g-1, 0.01-0.24 μg g-1 and 0.01-4.86 μg g-1, respectively. Subject #8 has the highest amount of the detected substances in both left and right ear, with Δ9-THC at a concentration of 1.85 and 4.86 μg g-1, CBG 0.06 and 0.24 μg g-1, CBN 0.10 and 0.21 μg g-1, respectively. In addition, a detection window for the substances Δ9-Tetrahydrocannabinol, Cannabinol and Cannabigerol, in cerumen, was defined with success. In this case, Δ9-THC reached a maximum detection frame of up to fifteen days after smoking 0.5 g of marijuana cigarette. ANOVA-one-way analysis also indicated that the average earwax production of non-cannabis users differs significantly from the one of cannabis users (p = 0.048, <0.05). On the other hand, no significant difference was noticed between male and female users as the p value exceeded 0.05. In addition, no significant effect was observed on earwax production in regard to age, frequency and the last time of use (p > 0.05). These last three factors proved to have a significant impact on cannabinoids concentrations, since p values were less than 0.05.
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Affiliation(s)
| | - M S Constantinou
- Analytical Department, MC Analysis Centre LTD, 2563 Nicosia, Cyprus
| | - A P Louppis
- Analytical Department, MC Analysis Centre LTD, 2563 Nicosia, Cyprus
| | - A Christou
- Department of Chemistry, University of Cyprus, 1678 Nicosia, Cyprus
| | - I J Stavrou
- Department of Life Sciences, European University Cyprus, 2404 Nicosia, Cyprus
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Christodoulou MC, Christou A, Stavrou IJ, Kapnissi-Christodoulou CP. Evaluation of different extraction procedures for the quantification of seven cannabinoids in cannabis-based edibles by the use of LC-MS. J Food Compost Anal 2023. [DOI: 10.1016/j.jfca.2022.104915] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Ioannou KA, Christou A, Stavrou IJ, Schmid MG, Kapnissi-Christodoulou CP. Evaluation of cyclodextrin- and cyclofructan-based chiral selectors for the enantioseparation of psychoactive substances in capillary electrophoresis. Electrophoresis 2022; 43:2392-2401. [PMID: 36189902 DOI: 10.1002/elps.202200182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 09/09/2022] [Accepted: 09/23/2022] [Indexed: 11/05/2022]
Abstract
During this study, a simple and easy-to-prepare electrophoretic method was developed for the enantioseparation of amphetamine and cathinone derivatives. Different types of β-cyclodextrin and cyclofructan-based chiral selectors (CSs), both native and derivatized, were utilized, and the most effective ones, in terms of resolution and analysis time, were identified. In addition, several electrophoretic parameters, such as background electrolyte concentration and pH, and CS concentration, were examined to optimize the separation conditions. Under the optimal electrophoretic conditions, 10 psychoactive substances were enantiomerically separated using 1 mM sulfated cyclofructan-6 (SCF-6) for the amphetamine derivatives and 1 mM sulfated cyclofructan-7 (SCF-7) for the cathinone derivatives dissolved in an aqueous solution of 20-mM monobasic sodium phosphate at pH 2.5, a temperature of 25°C, and an applied voltage of 25 kV. In addition, the method was validated by estimating the intra- and interday precision.
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Affiliation(s)
| | | | - Ioannis J Stavrou
- Department of Life Sciences, European University Cyprus, Nicosia, Cyprus
| | - Martin G Schmid
- Department of Pharmaceutical Chemistry, Institute of Pharmaceutical Sciences, University of Graz, Graz, Austria
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Christou A, Stavrou IJ, Kapnissi-Christodoulou CP. Continuous and pulsed ultrasound-assisted extraction of carob's antioxidants: Processing parameters optimization and identification of polyphenolic composition. Ultrason Sonochem 2021; 76:105630. [PMID: 34146974 PMCID: PMC8220390 DOI: 10.1016/j.ultsonch.2021.105630] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/27/2021] [Accepted: 06/10/2021] [Indexed: 05/19/2023]
Abstract
Polyphenols in carobs have recently attracted great attention due to their wide range of biological and health promoting effects. A comprehensive study was conducted to find an optimum method for the extraction, purification and characterization of these valuable bioactive substances. Under this framework, the ultrasound-assisted extraction (UAE) of polyphenols from carob pulp was optimized by the maximization of the yield in total phenolics using response surface methodology. In particular, the effects of solid-solvent ratio, solvent concentration, extraction time, sonication amplitude, and sonication mode were investigated and optimized using a complete experimental design. In comparison to conventional extraction techniques, UAE offered a higher yield of antioxidants and a shorter processing time. Solid-phase extraction was evaluated as a clean-up strategy prior to the electrophoretic analysis of extracts. The results from the analysis of real samples revealed the predominance of gallic acid and highlighted the great influence of the ripening stage on carobs composition.
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Affiliation(s)
| | - Ioannis J Stavrou
- Department of Life Sciences, European University Cyprus, 2404 Nicosia, Cyprus
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Christou A, Stavrou IJ, Kapnissi-Christodoulou CP. Combined use of β-cyclodextrin and ionic liquid as electrolyte additives in EKC for separation and determination of carob's phenolics-A study of the synergistic effect. Electrophoresis 2021; 42:1945-1955. [PMID: 34240758 DOI: 10.1002/elps.202100085] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 06/25/2021] [Accepted: 06/29/2021] [Indexed: 11/11/2022]
Abstract
In this work, a simple, reliable, and fast capillary electrophoretic method was developed and validated for the simultaneous determination of 12 polyphenolic compounds, the most frequently found in carob's pulp and seeds. The present work deals with the development of a novel dual electrophoretic system based on the combined use of β-CD and ionic liquid (IL) as buffer additives. A baseline separation of the target analytes was achieved in less than 10 min by using a BGE consisting of 35 mM borate along with 15 mM β-CD and 3 mM l-alanine tert butyl ester lactate (l-AlaC4 Lac) IL as buffer additives at pH 9.5, a temperature of 25°C, and an applied voltage of 30 kV. The application of the developed electrophoretic method to real samples enabled the identification and quantification of the main phenolic constituents of both ripe and unripe carob pulp extracts. The results revealed the predominance of gallic acid in both ripe (183.92 μg/g carob pulp) and unripe (205.10 μg/g carob pulp) carob pulp and highlighted the great influence of the ripening stage on carobs polyphenolic composition, with unripe pods being more enriched in polyphenols (total phenolics detected: 912.58 and 283.13 μg/g unripe and ripe carob pulp).
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Affiliation(s)
| | - Ioannis J Stavrou
- Department of Life Sciences, European University Cyprus, Nicosia, Cyprus
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Stavrou IJ, Christou A, Kapnissi-Christodoulou CP. Polyphenols in carobs: A review on their composition, antioxidant capacity and cytotoxic effects, and health impact. Food Chem 2018; 269:355-374. [DOI: 10.1016/j.foodchem.2018.06.152] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 06/29/2018] [Accepted: 06/30/2018] [Indexed: 01/06/2023]
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Nicolaou AG, Mavroudi MC, Stavrou IJ, Weatherly CA, Kapnissi-Christodoulou CP. Synergistic enantioseparation systems with either cyclodextrins or cyclofructans and L-alanine Tert butyl ester lactate. Electrophoresis 2018; 40:539-546. [PMID: 30450594 DOI: 10.1002/elps.201800257] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 10/18/2018] [Accepted: 11/13/2018] [Indexed: 11/06/2022]
Abstract
The combined use of chiral ionic liquids (CILs) and conventional chiral selectors (CSs) in CE, to establish a synergistic system, has proven to be an effective approach for the separation of enantiomeric pairs. In this study, a new CE method was developed, employing a binary system of a CS, either a cyclodextrin (CD) or a cyclofructan (CF), and a chiral amino acid ester-based ionic liquid (AAIL), for the chiral separation of four basic, acidic and zwitterionic drug compounds. In particular, the enantioseparation of two anticoagulants, warfarin (WAR) and coumachlor (COU), a non-opioid analgesic, nefopam (NEF) and a third-generation antihistamine, fexofenadine (FXD), was examined, by supporting the BGE with a CS and the chiral AAIL L-alanine tert butyl ester lactate (L-AlaC4 Lac). Parameters, such as the type of the CS, the concentration of both the CS and L-AlaC4 Lac, and the BGE pH, were methodically examined in order to optimize the chiral separation of each analyte. It was observed that, in some cases, the addition of the AAIL into the BGE improved both resolution (Rs ) and efficiency (N) significantly. In other cases, the synergistic effect enabled baseline separation of analyte enantiomers, at a much lower concentration of the CS. Finally, after optimization of separation conditions, baseline separations (Rs >1.5) of all four analytes were achieved in less than 5 min.
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Stavrou IJ, Agathokleous EA, Kapnissi-Christodoulou CP. Chiral selectors in CE: Recent development and applications (mid-2014 to mid-2016). Electrophoresis 2017; 38:786-819. [DOI: 10.1002/elps.201600322] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 11/22/2016] [Accepted: 11/23/2016] [Indexed: 11/05/2022]
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Mitrofan G, Stefan-van Staden RI, Comnea-Stancu IR, van Staden JF, Bazylak G, Kapnissi-Christodoulou CP, Aboul-Enein HY. Fast Screening of Whole Blood Samples and Pharmaceutical Compounds for Enantiorecognition of Free L-T3 , L-T4 , and D-T4. Chirality 2015; 27:973-8. [PMID: 26447904 DOI: 10.1002/chir.22537] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Revised: 08/14/2015] [Accepted: 08/26/2015] [Indexed: 12/16/2022]
Abstract
A fast screening method of whole blood was proposed for enantiorecognition of free L-T3 , L-T4 , and D-T4 . Stochastic microsensors based on four inulins (IN, IQ, TEX, and HD) immobilized on diamond paste (DP) were used for recognition of free L-T3 , L-T4 , and D-T4 . For the enantiorecognition of free L-T4 and D-T4 in whole blood and pharmaceutical samples, the best microsensor was the one based on TEX/DP (wide linear concentration ranges, and low limits of quantification). The best limit of detection for the assay of free L-T3 (400 fmol/L) was recorded using the microsensors based on HD/DP, while for the assay of free L-T4, and D-T4 the best limit of determination (1 pmol/L) was recorded using the TX/DP-based microsensor. For the enantiorecognition of free L-T3 in whole blood and pharmaceutical samples the best microsensor was the one based on HD/DP (the wider linear concentration range, and the lower limit of quantification - of pmol/L magnitude order). For the enantiorecognition of free L-T3 in whole blood and pharmaceutical samples the best microsensor was the one based on HD/DP (the wider linear concentration range, and the lower limit of quantification - of pmol/L magnitude order). Free L-T3 , L-T4 , and D-T4 were recovered with high reliabilities in whole blood samples (recoveries higher than 99.00%, with RSD values lower than 1.00%) and pharmaceutical samples (recoveries higher than 95.00% with RSD values lower than 1.00%).
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Affiliation(s)
- Grigorina Mitrofan
- Faculty of Applied Chemistry and Materials Science, Politehnica University of Bucharest, Bucharest, Romania
| | - Raluca-Ioana Stefan-van Staden
- Faculty of Applied Chemistry and Materials Science, Politehnica University of Bucharest, Bucharest, Romania.,Laboratory of Electrochemistry and PATLAB Bucharest, National Institute of Research for Electrochemistry and Condensed Matter, Bucharest, Romania
| | - Ionela Raluca Comnea-Stancu
- Laboratory of Electrochemistry and PATLAB Bucharest, National Institute of Research for Electrochemistry and Condensed Matter, Bucharest, Romania
| | - Jacobus Frederick van Staden
- Laboratory of Electrochemistry and PATLAB Bucharest, National Institute of Research for Electrochemistry and Condensed Matter, Bucharest, Romania
| | - Grzegorz Bazylak
- Pharmaco-Bromatology & Molecular Nutrition, Faculty of Pharmacy, Nicolaus Copernicus University, Bydgoszcz, Poland
| | | | - Hassan Y Aboul-Enein
- Pharmaceutical and Medicinal Chemistry, Pharmaceutical and Drug Industries Research Division, National Research Centre, Giza, Egypt
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Stavrou IJ, Breitbach ZS, Kapnissi-Christodoulou CP. Combined use of cyclofructans and an amino acid ester-based ionic liquid for the enantioseparation of huperzine A and coumarin derivatives in CE. Electrophoresis 2015; 36:3061-8. [DOI: 10.1002/elps.201500367] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 08/27/2015] [Accepted: 08/28/2015] [Indexed: 01/03/2023]
Affiliation(s)
| | - Zachary S. Breitbach
- Department of Chemistry and Biochemistry; University of Texas at Arlington; Arlington USA
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Georgiou CA, Constantinou MS, Andreou R, Hapeshi E, Fatta-Kassinos D, Kapnissi-Christodoulou CP. Novel approach to fast determination of cholesterol oxidation products in Cypriot foodstuffs using ultra-performance liquid chromatography-tandem mass spectrometry. Electrophoresis 2015; 37:1101-8. [DOI: 10.1002/elps.201500196] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Revised: 07/23/2015] [Accepted: 08/10/2015] [Indexed: 12/14/2022]
Affiliation(s)
| | | | | | - Evroula Hapeshi
- Department of Civil and Environmental Engineering; University of Cyprus; Nicosia Cyprus
| | - Despo Fatta-Kassinos
- Department of Civil and Environmental Engineering; University of Cyprus; Nicosia Cyprus
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Mavroudi MC, Kapnissi-Christodoulou CP. Combined use ofl-alanine tert butyl ester lactate and trimethyl-β-cyclodextrin for the enantiomeric separations of 2-arylpropionic acids nonsteroidal anti-inflammatory drugs. Electrophoresis 2015; 36:2442-50. [DOI: 10.1002/elps.201500143] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 05/21/2015] [Accepted: 05/21/2015] [Indexed: 11/07/2022]
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Kapnissi-Christodoulou CP, Stavrou IJ, Mavroudi MC. Chiral ionic liquids in chromatographic and electrophoretic separations. J Chromatogr A 2014; 1363:2-10. [DOI: 10.1016/j.chroma.2014.05.059] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 05/17/2014] [Accepted: 05/20/2014] [Indexed: 02/07/2023]
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Mavroudi MC, Kapnissi-Christodoulou CP. Evaluation of amino acid ester-based ionic liquids as buffer additives in CE for the separation of 2-arylpropionic acids nonsteroidal anti-inflammatory drugs. Electrophoresis 2014; 35:2573-8. [DOI: 10.1002/elps.201400165] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2014] [Revised: 05/16/2014] [Accepted: 05/16/2014] [Indexed: 11/10/2022]
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Abstract
In this study, the applicability of a chiral ionic liquid (CIL) as the sole chiral selector in CE was investigated for the first time. In particular, five amino acid ester-based CILs were synthesized and used as additives in the BGE in order to evaluate their chiral recognition ability. The performance of these CILs as the sole chiral selectors was evaluated by using 1,1'-binaphthyl-2,2-diylhydrogenphosphate (BNP) as the analyte and by comparing the resolution values. Different parameters were examined, such as the alkyl group bulkiness and the configuration of the cation, the anion type of the CIL and its concentration, and the pH of the BGE, in order to optimize the separation of the enantiomers and to demonstrate the effect that each parameter has on the chiral-recognition ability of the CIL. Baseline separation of BNP within 13 min was achieved by using a BGE of 100 mM Tris/10 mM sodium tetraboratedecahydrate (pH 8) and a chiral selector of 60 mM l-alanine tert butyl ester lactate. The run-to-run and batch-to-batch reproducibilities were also evaluated by computing the %RSD values of the EOF and the two enantiomer peaks. In both cases, very good reproducibilities were observed, since all %RSD values were below 1%.
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20
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Hadjistasi CA, Stavrou IJ, Stefan-Van Staden RI, Aboul-Enein HY, Kapnissi-Christodoulou CP. Chiral Separation of the Clinically Important Compounds Fucose and Pipecolic Acid Using CE: Determination of the Most Effective Chiral Selector. Chirality 2013; 25:556-60. [DOI: 10.1002/chir.22170] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2012] [Accepted: 02/12/2013] [Indexed: 11/07/2022]
Affiliation(s)
| | | | - Raluca-Ioana Stefan-Van Staden
- Laboratory of Electrochemistry and PATLAB Bucharest; National Institute of Research for Electrochemistry and Condensed Matter; Bucharest Romania
| | - Hassan Y. Aboul-Enein
- Pharmaceutical and Medicinal Chemistry Department; The Pharmaceutical and Drug Industries Research Division, National Research Centre; Cairo Egypt
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Tsioupi DA, Stefan-Vanstaden RI, Kapnissi-Christodoulou CP. Chiral selectors in CE: recent developments and applications. Electrophoresis 2013; 34:178-204. [PMID: 23161372 DOI: 10.1002/elps.201200239] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 08/14/2012] [Accepted: 08/14/2012] [Indexed: 01/01/2023]
Abstract
This review article provides an overview of the recent advances in enantioanalysis by use of electrophoretic techniques. Due to the big number of publications in the subject mentioned above, this article is focused on chiral method developments and applications published from 2008 until 2011, and it demonstrates chiral selectors used in CE. Numerous chiral selectors have been used over the years, and these include the cyclic and the linear oligo- and polysaccharides, the branched polysaccharides, the polymeric and monomeric surfactants, the macrocyclic and other antibiotics, and the crown ethers. Different dual-selector systems are also presented in this article, and the results are compared with those obtained by use of a single chiral selector. Finally, several pharmaceutical and biomedical applications based on chiral recognition are summarized.
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Stavrou IJ, Moore L, Fernand VE, Kapnissi-Christodoulou CP, Warner IM. Facile preparation of polysaccharide-coated capillaries using a room temperature ionic liquid for chiral separations. Electrophoresis 2013; 34:1334-8. [DOI: 10.1002/elps.201200563] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 01/24/2013] [Accepted: 02/17/2013] [Indexed: 11/06/2022]
Affiliation(s)
| | - Leonard Moore
- Department of Chemistry; Louisiana State University; Baton Rouge; LA; USA
| | - Vivian E. Fernand
- Department of Chemistry; Louisiana State University; Baton Rouge; LA; USA
| | | | - Isiah M. Warner
- Department of Chemistry; Louisiana State University; Baton Rouge; LA; USA
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Stavrou IJ, Kapnissi-Christodoulou CP. Use of chiral amino acid ester-based ionic liquids as chiral selectors in CE. Electrophoresis 2013. [PMID: 23208781 DOI: 10.1002/elps.v34.410.1002/elps.201200469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
In this study, the applicability of a chiral ionic liquid (CIL) as the sole chiral selector in CE was investigated for the first time. In particular, five amino acid ester-based CILs were synthesized and used as additives in the BGE in order to evaluate their chiral recognition ability. The performance of these CILs as the sole chiral selectors was evaluated by using 1,1'-binaphthyl-2,2-diylhydrogenphosphate (BNP) as the analyte and by comparing the resolution values. Different parameters were examined, such as the alkyl group bulkiness and the configuration of the cation, the anion type of the CIL and its concentration, and the pH of the BGE, in order to optimize the separation of the enantiomers and to demonstrate the effect that each parameter has on the chiral-recognition ability of the CIL. Baseline separation of BNP within 13 min was achieved by using a BGE of 100 mM Tris/10 mM sodium tetraboratedecahydrate (pH 8) and a chiral selector of 60 mM l-alanine tert butyl ester lactate. The run-to-run and batch-to-batch reproducibilities were also evaluated by computing the %RSD values of the EOF and the two enantiomer peaks. In both cases, very good reproducibilities were observed, since all %RSD values were below 1%.
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Nicolaou IN, Kapnissi-Christodoulou CP. Development of a capillary electrophoresis-mass spectrometry method for the determination of rivastigmine in human plasma - Optimization of the limits of detection and quantitation. Electrophoresis 2012; 33:644-52. [DOI: 10.1002/elps.201100286] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Tsioupi DA, Nicolaou IN, Moore L, Kapnissi-Christodoulou CP. Chiral separation of Huperzine A using CE - Method validation and application in pharmaceutical formulations. Electrophoresis 2012; 33:516-22. [DOI: 10.1002/elps.201100372] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 08/26/2011] [Accepted: 09/15/2011] [Indexed: 11/07/2022]
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Nicolaou IN, Kapnissi-Christodoulou CP. Analysis of polyphenols using capillary zone electrophoresis - Determination of the most effective wine sample pre-treatment method. Electrophoresis 2010; 31:3895-902. [DOI: 10.1002/elps.201000316] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Kapnissi-Christodoulou CP, Lowry M, Agbaria RA, Geng L, Warner IM. Investigation of the stability of polyelectrolyte multilayer coatings in open-tubular capillary electrochromatography using laser scanning confocal microscopy. Electrophoresis 2005; 26:783-789. [PMID: 15714571 DOI: 10.1002/elps.200410256] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A simple polyelectrolyte multilayer (PEM) coating procedure was used for the development of stable modified capillaries. PEM coatings were constructed in fused-silica capillaries using alternating rinses of cationic and anionic polyelectrolytes. The multilayer coatings investigated in this study consisted of two and twenty layer pairs, or bilayers. A bilayer is one layer of a cationic polymer and one layer of an anionic polymer. Poly(diallyldimethylammonium chloride) was used as the cationic polymer, and the polymeric surfactant poly(sodium N-undecanoyl-L-leucylvalinate) was used as the anionic polymer. Previous studies for both chiral and achiral separations have shown that PEM-coated capillaries have excellent reproducibilities, remarkable endurance, and strong stabilities against extreme pH values when used in open-tubular capillary electrochromatography (OT-CEC). In this study, the stability of the coatings was further investigated after exposure to 0.1 M and 1.0 M NaOH. Structural changes of these coatings were monitored using laser scanning confocal microscopy (LSCM) after flushing the capillaries with NaOH. This technique allowed observation of the degradation of the coatings. Observations are discussed in terms of separations using OT-CEC. Electropherograms obtained from the chiral separation of 1,1'-binaphthyl-2,2'-dihydrogenphosphate in OT-CEC showed a decrease in selectivity and an increase in electroosmotic mobility after long exposure to NaOH. The ability to recover the capillaries by exposure to NaOH was also demonstrated. Measurements of electroosmotic mobility and selectivity showed that 2-bilayer and 20-bilayer PEM coatings could be completely removed from the capillary surface after approximately 3.5 and 9.5 h, respectively, of continuous exposure to 1 M NaOH.
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Abstract
This review represents a summary of recent progress in open-tubular capillary electrochromatography (OT-CEC) for chiral and achiral separations. The OT-CEC approach is an alternative to packed-CEC that could eliminate the problems associated with retaining frits and silica particles. In OT-CEC, the stationary phase is immobilized on the inner walls of the capillary. Preparation of the stationary phase is critical for OT-CEC. The preparation methods for capillary columns include (i) adsorption, (ii) covalent bonding and/or cross-linking, (iii) porous layers, (iv) chemical bonding after etching, (v) sol-gel, and (vi) molecular imprinting. Major developments, potential applications, technical difficulties and advantages associated with these wall coatings in OT-CEC are presented. In addition, the coupling of OT-CEC with mass spectrometry (MS) is briefly reviewed. Several applications of this hyphenated technique for analytical separations are also summarized.
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