Direct electrochemistry of hemoglobin and myoglobin at didodecyldimethylammonium bromide-modified powder microelectrode and application for electrochemical detection of nitric oxide

摘要

Hemoglobin(Hb)and myoglobin(Mb)were immobilized at the didodecyldimethylammonium bromide(DDAB)-modified powder microelectrode(PME)to fabricate Hb-DDAB-PME and Mb-DDAB-PME.Direct electrochemistry of Hb and Mb were achieved on the DDAB-modified PME.The formal potential was-0.224V for Hb and-0.212 V for Mb(vs.SCE).The apparent surface concentration of Hb and Mb at the electrode surface was 2.83X10~(-8)and 9.94X10~(-8)mol cm~(-2).The Hb-DDAB-PME and Mb-DDAB-PME were successfully applied for measurement of NO in vitro.The anodic current peaks for NO oxidation at+0.7 V and the cathodic current peaks for NO reduction at-0.85 V on the CV curves were obtained on the modified electrodes.For detection of NO at+0.7 V,the sensitivity is 3.31 mA mu M~(-1)cm~(-2)for Hb-DDAB-PME and 0.6 mA mu M~(-1)cm~(-2)for Mb-DDAB-PME.The detection limit is 5 nM for Hb-DDAB-PME and 9 nM for Mb-DDAB-PME.The linear response range is 9-100 and 28-330 nM for Hb-and Mb-modified PME,respectively.For the electrochemical detection of NO at-0.85 V by using Hb-DDAB-PME,the detection sensitivity is 39.56 mu A MU M~(-1)cm~(-2);the detection limit is as low as 0.2 mu M;and the linear response range is 1.90-28.08 mu M.