Application of hollow fibre based microextraction for voltammetric determination of vanillylmandelic acid in human urine

• Published in: Journal of electroanalytical chemistry (Lausanne, Switzerland) Vol. 835; pp. 130 - 136
• Main Authors: Hrdlička, Vojtěch, Navrátil, Tomáš, Barek, Jiří
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15-02-2019; Elsevier Science Ltd
• Subjects: Biomarker; Biomarkers; Boron; Boron doped diamond electrode (BDDE); Diamonds; Hollow fibre; Human wastes; Liquid phase microextraction; Sodium hydroxide; Urine; Vanillylmandelic acid (VMA); Voltammetry; Voltammetry; Vanillylmandelic acid (VMA); Biomarker; Boron doped diamond electrode (BDDE); Hollow fibre; Liquid phase microextraction
• ISSN: 1572-6657; 1873-2569
• DOI: 10.1016/j.jelechem.2018.12.060

A new hollow-fibre microextraction method has been developed for the determination of a clinical biomarker vanillylmandelic acid (VMA) in human urine. The extraction was used in combination with differential pulse voltammetry (DPV) on cathodically pre-treated boron doped diamond electrode (BDDE). Butyl benzoate was found to be the optimum solvent for creation of supported liquid membrane. Optimum donor and acceptor phases were 0.1 mol L−1 HCl and 0.1 mol L−1 NaOH, respectively, optimum extraction time was 30 min. Linear range was from 0.5 to 100 μmol L−1 (r = 0.9989), with good repeatability (RSD 7.9% for 50 μmol L−1 VMA aqueous sample (n = 7)). The limit of detection (LOD) was 0.5 μmol L−1. The method was successfully applied for the determination of VMA in real human urine sample using a standard addition method, obtained RSD being 8.1% (n = 5). The method is sufficiently selective and sensitive for its intended use as a screening tool for elevated concentration of VMA.
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•New hollow-fibre microextraction determination of vanillylmandelic acid•Microextraction combined with differential pulse voltammetry•Cathodically pre-treated boron doped diamond working electrode•Environmentally-friendly solvent butyl benzoate as supported liquid membrane•Method verified using real human urine sample