Investigation of Imidazolium-Based Ionic Liquids as Additives for the Separation of Urinary Biogenic Amines via Capillary Electrophoresis
Ionic liquids (ILs), such as imidazoles, can be used to prevent the sorption of analytes onto the walls of the capillary. Prior works have confirmed that coating the capillary wall with a cationic layer can increase its surface stability, thereby improving the repeatability of the separation process...
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MDPI AG
2023-02-01
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| Online Access: | https://www.mdpi.com/2297-8739/10/2/116 |
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| author | Natalia Kaczmarczyk Natalia Treder Piotr Kowalski Alina Plenis Anna Roszkowska Tomasz Bączek Ilona Olędzka |
| author_facet | Natalia Kaczmarczyk Natalia Treder Piotr Kowalski Alina Plenis Anna Roszkowska Tomasz Bączek Ilona Olędzka |
| author_sort | Natalia Kaczmarczyk |
| collection | DOAJ |
| description | Ionic liquids (ILs), such as imidazoles, can be used to prevent the sorption of analytes onto the walls of the capillary. Prior works have confirmed that coating the capillary wall with a cationic layer can increase its surface stability, thereby improving the repeatability of the separation process. In this study, micellar electrokinetic chromatography (MEKC) is employed to evaluate how two ILs with different anions—namely, 1-hexyl-3-methylimidazolium chloride [HMIM<sup>+</sup>Cl<sup>−</sup>] and 1-hexyl-3-methylimidazolium tetrafluoroborate [HMIM<sup>+</sup>BF<sub>4</sub><sup>−</sup>]—affect the separation efficiency for biogenic amines (BAs) such as metanephrine (M), normetanephrine (NM), vanilmandelic acid (VMA), and homovanillic acid (HVA) in urine samples. To this end, solid-phase extraction (SPE) is employed using different sample pH values, with the results demonstrating that HVA and VMA is easily extracted at a sample pH of 5.5, while a sample pH of 9.0 facilitated the extraction of M and NM. In the applied SPE protocol, selected analytes were isolated from urine samples using hydrophilic–lipophilic-balanced (HLB) columns and eluted with methanol (MeOH). The validation data confirmed the method’s linearity (R<sup>2</sup> > 0.996) for all analytes within the range of 0.25–10 µg/mL. The applicability of the optimized SPE-MEKC-UV method was confirmed by employing it to quantify clinically relevant BAs in real urine samples from pediatric neuroblastoma (NBL) patients. |
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| institution | Directory Open Access Journal |
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| language | English |
| last_indexed | 2024-03-11T08:10:01Z |
| publishDate | 2023-02-01 |
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| record_format | Article |
| series | Separations |
| spelling | doaj.art-8f062dbe7a4e4b709ae2fc22f003d1c52023-11-16T23:14:33ZengMDPI AGSeparations2297-87392023-02-0110211610.3390/separations10020116Investigation of Imidazolium-Based Ionic Liquids as Additives for the Separation of Urinary Biogenic Amines via Capillary ElectrophoresisNatalia Kaczmarczyk0Natalia Treder1Piotr Kowalski2Alina Plenis3Anna Roszkowska4Tomasz Bączek5Ilona Olędzka6Department of Pharmaceutical Chemistry, Medical University of Gdańsk, Hallera 107, 80-416 Gdańsk, PolandDepartment of Pharmaceutical Chemistry, Medical University of Gdańsk, Hallera 107, 80-416 Gdańsk, PolandDepartment of Pharmaceutical Chemistry, Medical University of Gdańsk, Hallera 107, 80-416 Gdańsk, PolandDepartment of Analytical Chemistry, Medical University of Gdańsk, Hallera 107, 80-416 Gdańsk, PolandDepartment of Pharmaceutical Chemistry, Medical University of Gdańsk, Hallera 107, 80-416 Gdańsk, PolandDepartment of Pharmaceutical Chemistry, Medical University of Gdańsk, Hallera 107, 80-416 Gdańsk, PolandDepartment of Pharmaceutical Chemistry, Medical University of Gdańsk, Hallera 107, 80-416 Gdańsk, PolandIonic liquids (ILs), such as imidazoles, can be used to prevent the sorption of analytes onto the walls of the capillary. Prior works have confirmed that coating the capillary wall with a cationic layer can increase its surface stability, thereby improving the repeatability of the separation process. In this study, micellar electrokinetic chromatography (MEKC) is employed to evaluate how two ILs with different anions—namely, 1-hexyl-3-methylimidazolium chloride [HMIM<sup>+</sup>Cl<sup>−</sup>] and 1-hexyl-3-methylimidazolium tetrafluoroborate [HMIM<sup>+</sup>BF<sub>4</sub><sup>−</sup>]—affect the separation efficiency for biogenic amines (BAs) such as metanephrine (M), normetanephrine (NM), vanilmandelic acid (VMA), and homovanillic acid (HVA) in urine samples. To this end, solid-phase extraction (SPE) is employed using different sample pH values, with the results demonstrating that HVA and VMA is easily extracted at a sample pH of 5.5, while a sample pH of 9.0 facilitated the extraction of M and NM. In the applied SPE protocol, selected analytes were isolated from urine samples using hydrophilic–lipophilic-balanced (HLB) columns and eluted with methanol (MeOH). The validation data confirmed the method’s linearity (R<sup>2</sup> > 0.996) for all analytes within the range of 0.25–10 µg/mL. The applicability of the optimized SPE-MEKC-UV method was confirmed by employing it to quantify clinically relevant BAs in real urine samples from pediatric neuroblastoma (NBL) patients.https://www.mdpi.com/2297-8739/10/2/116metanephrines (MNs)vanilmandelic acid (VMA)homovanillic acid (HVA)micellar electrokinetic chromatography (MEKC)solid-phase extraction (SPE)urine samples |
| spellingShingle | Natalia Kaczmarczyk Natalia Treder Piotr Kowalski Alina Plenis Anna Roszkowska Tomasz Bączek Ilona Olędzka Investigation of Imidazolium-Based Ionic Liquids as Additives for the Separation of Urinary Biogenic Amines via Capillary Electrophoresis Separations metanephrines (MNs) vanilmandelic acid (VMA) homovanillic acid (HVA) micellar electrokinetic chromatography (MEKC) solid-phase extraction (SPE) urine samples |
| title | Investigation of Imidazolium-Based Ionic Liquids as Additives for the Separation of Urinary Biogenic Amines via Capillary Electrophoresis |
| title_full | Investigation of Imidazolium-Based Ionic Liquids as Additives for the Separation of Urinary Biogenic Amines via Capillary Electrophoresis |
| title_fullStr | Investigation of Imidazolium-Based Ionic Liquids as Additives for the Separation of Urinary Biogenic Amines via Capillary Electrophoresis |
| title_full_unstemmed | Investigation of Imidazolium-Based Ionic Liquids as Additives for the Separation of Urinary Biogenic Amines via Capillary Electrophoresis |
| title_short | Investigation of Imidazolium-Based Ionic Liquids as Additives for the Separation of Urinary Biogenic Amines via Capillary Electrophoresis |
| title_sort | investigation of imidazolium based ionic liquids as additives for the separation of urinary biogenic amines via capillary electrophoresis |
| topic | metanephrines (MNs) vanilmandelic acid (VMA) homovanillic acid (HVA) micellar electrokinetic chromatography (MEKC) solid-phase extraction (SPE) urine samples |
| url | https://www.mdpi.com/2297-8739/10/2/116 |
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