title: Halloysite clay nanotubes and platinum nanoparticles dispersed in ionic liquid applied in the development of a catecholamine biosensor.
abstract: Halloysite clay nanotubes were used as a support for the immobilization of the enzyme peroxidase from clover sprouts (Trifolium), and employed together with platinum nanoparticles in 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid (Pt-BMI·PF(6)) in the development of a new biosensor for the determination of catecholamines by square-wave voltammetry. Under optimized conditions, the analytical curves showed detection limits of 0.05, 0.06, 0.07, 0.12 μM for dopamine, isoproterenol, dobutamine and epinephrine, respectively. The biosensor demonstrated high sensitivity, good repeatability and reproducibility, and long-term stability (18% decrease in response over 150 days). A recovery study of dopamine in pharmaceutical samples gave values from 97.5 to 101.4%. The proposed biosensor was successfully applied to the determination of dopamine in pharmaceutical samples, with a maximum relative error of ±1.0% in relation to the standard (spectrophotometric) method. The good analytical performance of the proposed method can be attributed to the efficient immobilization of the peroxidase in the nanoclay, and the facilitation of electron transfer between the protein and the electrode surface due to the presence of the Pt nanoparticles and ionic liquid.
authors: Department of Chemistry, Laboratory of Biosensors, Federal University of Santa Catarina, 88040-970, Florianópolis, SC, Brazil. danielabrondani@hotmail.com
authors: Daniela
authors: D
authors: Brondani
authors: Carla Weber
authors: CW
authors: Scheeren
authors: Jairton
authors: J
authors: Dupont
authors: Iolanda Cruz
authors: IC
authors: Vieira
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D002395:Catecholamines / Q000032:analysis*; D000077215:Clay; D004563:Electrochemistry; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007093:Imidazoles / Q000737:chemistry; D052578:Ionic Liquids / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D043942:Nanotubes / Q000737:chemistry*; D010544:Peroxidases / Q000737:chemistry / Q000378:metabolism; D010984:Platinum / Q000737:chemistry*; D029921:Trifolium / Q000201:enzymology
chemical_list: C412621:1-butyl-3-methylimidazolium hexafluorophosphate; D000538:Aluminum Silicates; D002395:Catecholamines; D004800:Enzymes, Immobilized; D007093:Imidazoles; D052578:Ionic Liquids; D010984:Platinum; D010544:Peroxidases; D000077215:Clay