Investigation of Imidazolium-Based Ionic Liquids as Additives for the Separation of Urinary Biogenic Amines via Capillary Electrophoresis

Separations

article

Natalia Kaczmarczyk¹  Natalia Treder¹  Piotr Kowalski¹  Alina Plenis²  Anna Roszkowska¹  Tomasz Bączek¹  Ilona Olędzka¹ 

[1] Department of Pharmaceutical Chemistry, Medical University of Gdańsk;Department of Analytical Chemistry, Medical University of Gdańsk

关键词: metanephrines (MNs);    vanilmandelic acid (VMA);    homovanillic acid (HVA);    micellar electrokinetic chromatography (MEKC);    solid-phase extraction (SPE);    urine samples;    neuroendocrine tumors (NETs);    neuroblastoma (NBL);   

DOI  :  10.3390/separations10020116

学科分类：社会科学、人文和艺术（综合）

来源: mdpi

【 摘 要 】

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+Cl−] and 1-hexyl-3-methylimidazolium tetrafluoroborate [HMIM+BF4−]—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 (R2 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.

【 授权许可】

CC BY