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A novel third-generation hydrogen peroxide(H_2O_2) biosensor(Hb/CdS/MWNTs/GCE) was fabricated through hemoglobin(Hb) adsorbed onto the mercaptoacetic acid modified CdS QDs/carboxyl multiwall carbon nanotubes’(MWNTs) films.Cyclic voltammogram of Hb/CdS/MWNTs/GCE showed a pair of well-defined and quasi-reversible redox peaks with a formal potential(E~0) of-0.230 V(vs.Ag/AgCl) in 0.1 mol/L pH=8.0 phosphate buffer solution(PBS),which was the characteristic of the Hb heme Fe(Ⅲ)/Fe(Ⅱ) redox couple.The biosensor shows an excellent electrocatalytic activity to the reduction of H_2O_2.The response time of the designed biosensor to H_2O_2 at a potential of -0.30 V was less than 2 s and linear relationships were obtained in the concentration ranges of 2.0×10~(-6)—2.7×10~(-3) mol/L and 2.7×10~(-3)—7.7×10~(-3) mol/L with a detection limit of 3.0×10~(-7)mol/L(S/N=3).The apparent Michaelis-Menten constant K_m was estimated to be 1.324 mmol/L that illustrated the excellent biological activity of the fixed Hb.
A novel third-generation hydrogen peroxide (H_2O_2) biosensor (Hb / CdS / MWNTs / GCE) was fabricated through hemoglobin (Hb) adsorbed onto mercaptoacetic acid modified CdS QDs / carboxyl multiwall carbon nanotubes (MWNTs) films. Cyclic voltammogram of Hb / CdS / MWNTs / GCE showed a pair of well-defined and quasi-reversible redox peaks with a formal potential (E~0) of-0.230 V (vs.Ag/AgCl) in 0.1 mol / L pH = 8.0 phosphate buffer solution (PBS), which was the characteristic of the Hb heme Fe (III) / Fe (II) redox couple. The biosensor shows an excellent electrocatalytic activity to the reduction of H 2 O 2. The response time of the designed biosensor to H 2 O 2 at a potential of -0.30 V was less than 2 s and linear relationships were obtained in the concentration ranges of 2.0 × 10 -6 -6.7 × 10 -3 mol / L and 2.7 × 10 -3 -7.7 × The apparent Michaelis-Menten constant K_m was estimated to be 1.324 mmol / L that of 10 × (-3) mol / L with a detection limit of 3.0 × 10 -7 mol / L (S / N = 3) the excellent biological acti vity of the fixed Hb.