title: Amperometric nitrite sensor based on hemoglobin/colloidal gold nanoparticles immobilized on a glassy carbon electrode by a titania sol-gel film.
abstract: A novel amperometric nitrite sensor was developed based on the immobilization of hemoglobin/colloidal gold nanoparticles on a glassy carbon electrode by a titania sol-gel film. The sensor shows a pair of well-defined and nearly reversible cyclic voltammogram peaks for Hb Fe(III)/Fe(II) with a formal potential (E degrees ') of -0.370 V, and the peak-to-peak separation at 100 mV s(-1) was 66 mV vs. Ag/AgCl (3.0 M KCl) in a pH 6.9 phosphate buffer solution. The formal potential of the Hb Fe(III)/Fe(II) couple shifted linearly with pH with a slope of -50.0 mV/pH, indicating that electron transfer accompanies single-proton transportation. The sensor exhibited an excellent electrocatalytic response to the reduction of nitrite. The reduction overpotential was 0.45 V below that obtained at a colloidal gold nanoparticles/TiO2 sol-gel film-modified GCE. The linear range for nitrite determination for the sensor was 4.0 x 10(-6) to 3.5 x 10(-4) M, with a detection limit of 1.2 x 10(-6) M. The stability, repeatability and selectivity of the sensor were also evaluated.
authors.affiliation: College of Chemistry, Jilin University, Changchun, 130023, People's Republic of China.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Yang
authors.forename: Yu
authors.initials: Y
authors.lastname: Bai
authors.forename: Yancai
authors.initials: Y
authors.lastname: Li
authors.forename: Changqing
authors.initials: C
authors.lastname: Sun
mesh_terms: D002244:Carbon / Q000737:chemistry*; D003102:Colloids; D004563:Electrochemistry / Q000295:instrumentation*; D004566:Electrodes; D006046:Gold / Q000737:chemistry*; D006454:Hemoglobins / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D036103:Nanotechnology; D009573:Nitrites / Q000032:analysis*; D010316:Particle Size; D013057:Spectrum Analysis / Q000379:methods; D014025:Titanium / Q000737:chemistry*
chemical_list: D003102:Colloids; D006454:Hemoglobins; D009573:Nitrites; D002244:Carbon; D006046:Gold; D014025:Titanium