title: Fabrication of an amperometric D-amino acid biosensor based on nickel hexacyanoferrate polypyrrole hybrid film deposited on glassy carbon electrode.
abstract: A nickel hexacyanoferrate polypyrrole film was synthesized through an electrochemical two-step methodology leading to a very stable and homogenous robust hybrid film. A highly sensitive, specific and rapid amperometric D-amino acid biosensor was constructed by immobilizing D-amino acid oxidase on this film deposited over the surface of a glassy carbon electrode. The modified electrode was characterized by scanning electron microscopy, electrochemical impedance spectroscopy and Fourier transform infrared spectrophotometry. The biosensor showed optimum response within 1 s, when operated at 50 mV s(-1) in 0.01 M Tris HCl buffer, pH 7.0 at 30 °C. The biosensor exhibited excellent sensitivity with a detection limit of 1.5 µM (S/N = 3) for D-amino acids and wider linear range, 20-500 µM. Analytical recovery of added D-alanine (5 and 10 mM) in serum samples was 98.00 and 98.80 %, respectively. Within-batch and between-batch coefficients of variation in serum samples were 1.36 and 2.77 %, respectively. The enzyme electrode was used more than 50 times over 2 months, when stored at 4 °C. The proposed modified electrode exhibited sufficient mechanical and electrochemical stability and high sensitivity compared to earlier electrochemical D-amino acid biosensors. Interference by ascorbic acid and uric acid, the main interfering species in the biological samples, was negligible.
authors: Department of Biochemistry, M D University, Rohtak 124001, Haryana, India.
authors: Suman
authors: S
authors: Lata
authors: C S
authors: CS
authors: Pundir
mesh_terms: D000596:Amino Acids / Q000032:analysis* / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation*; D002244:Carbon / Q000737:chemistry*; D003217:Conductometry / Q000295:instrumentation*; D003605:D-Amino-Acid Oxidase / Q000737:chemistry*; D004566:Electrodes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005898:Glass / Q000737:chemistry; D008567:Membranes, Artificial; D009532:Nickel / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D011758:Pyrroles / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D008567:Membranes, Artificial; D011108:Polymers; D011758:Pyrroles; C067635:polypyrrole; D002244:Carbon; D009532:Nickel; D003605:D-Amino-Acid Oxidase