Electroanalysis of urinary L-dopa using tyrosinase immobilized on gold nanoelectrode ensembles

• Type: Article in International Scientific Journal
• Date: 2012

Authors

Ana Pinho (Author) Other; Subramanian Viswanathan (Author) Other; Susana Ribeiro (Author) Other; Maria Beatriz P P Prior Pinto Oliveira (Author) FFUP; Cristina Delerue Matos (Author) Other

Journal

Title: Journal of Applied Electrochemistry

Vol. 42

Pages: 131-137

ISSN: 0021-891X

Publisher: Springer Nature

Indexing

ISI Web of Knowledge - 6 Citations

Scopus - 6 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-002-CNC

DOI: 10.1007/s10800-012-0379-3

Abstract (EN): The performance of an amperometric biosensor constructed by associating tyrosinase (Tyr) enzyme with the advantages of a 3D gold nanoelectrode ensemble (GNEE) is evaluated in a flow-injection analysis (FIA) system for the analysis of Levodopa (L-dopa). GNEEs were fabricated by electroless deposition of the metal within the pores of polycarbonate track-etched membranes. A simple solvent etching procedure based on the solubility of polycarbonate membranes is adopted for the fabrication of the 3D GNEE. Afterwards, enzyme was immobilized onto preformed self-assembled monolayers of cysteamine on the 3D GNEEs (GNEE-Tyr) via cross-linking with glutaraldehyde. The experimental conditions of the FIA system, such as the detection potential (-0.200 V (vs. Ag/AgCl)) and flow rates (1.0 mL min(-1)) were optimized. Analytical responses for L-dopa were obtained in a wide concentration range between 1 x 10(-8) mol L-1 and 1 x 10(-2) mol L-1. The limit of quantification was found to be 1 x 10(-8) mol L-1 with a resultant % RSD of 7.23% (n = 5). The limit of detection was found to be 1 x 10(-9) mol L-1 (S/N = 3). The common interfering compounds namely, glucose (10 mmol L-1), ascorbic acid (10 mmol L-1), and urea (10 mmol L-1) were studied. The recovery of L-dopa (1 x 10(-7) mol L-1) from spiked urine samples was found to be 96%. Therefore, the developed method is adequate to be applied in the clinical analysis.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 7