title: Electrodeposition of gold-platinum alloy nanoparticles on ionic liquid-chitosan composite film and its application in fabricating an amperometric cholesterol biosensor.
abstract: An electrodeposition method was applied to form gold-platinum (AuPt) alloy nanoparticles on the glassy carbon electrode (GCE) modified with a mixture of an ionic liquid (IL) and chitosan (Ch) (AuPt-Ch-IL/GCE). AuPt nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical methods. AuPt-Ch-IL/GCE electrocatalyzed the reduction of H(2)O(2) and thus was suitable for the preparation of biosensors. Cholesterol oxidase (ChOx) was then, immobilized on the surface of the electrode by cross-linking ChOx and chitosan through addition of glutaraldehyde (ChOx/AuPt-Ch-IL/GCE). The fabricated biosensor exhibited two wide linear ranges of responses to cholesterol in the concentration ranges of 0.05-6.2 mM and 6.2-11.2 mM. The sensitivity of the biosensor was 90.7 μA mM(-1) cm(-2) and the limit of detection was 10 μM of cholesterol. The response time was less than 7 s. The Michaelis-Menten constant (K(m)) was found as 0.24 mM. The effect of the addition of 1 mM ascorbic acid and glucose was tested on the amperometric response of 0.5 mM cholesterol and no change in response current of cholesterol was observed.
authors.affiliation: Department of Chemistry, College of Sciences, Shiraz University, Shiraz 71454, Iran. safavi@chem.susc.ac.ir
authors.forename: Afsaneh
authors.initials: A
authors.lastname: Safavi
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Farjami
mesh_terms: D000497:Alloys / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation*; D048271:Chitosan / Q000737:chemistry*; D002784:Cholesterol / Q000032:analysis* / Q000737:chemistry; D002789:Cholesterol Oxidase / Q000737:chemistry*; D003217:Conductometry / Q000295:instrumentation*; D004595:Electroplating; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006046:Gold / Q000737:chemistry; D052578:Ionic Liquids / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D010984:Platinum / Q000737:chemistry
chemical_list: D000497:Alloys; D052578:Ionic Liquids; D010984:Platinum; D006046:Gold; D048271:Chitosan; D002784:Cholesterol; D002789:Cholesterol Oxidase