A methylene blue-mediated enzyme electrode for the determination of trace mercury(II), mercury(I), methylmercury, and mercury-glutathione complex.
A methylene blue-mediated enzyme biosensor has been developed for the detection of inhibitors including mercury(II), mercury(I), methylmercury, and mercury-glutathione complex. The inhibition to horseradish peroxidase was apparently reversible and noncompetitive in the presence of HgCl2 in less than 8 s and irreversibly inactivated when incubated with different concentrations of HgCl2 for 1-8 min. The binding site of horseradish peroxidase with HgCl2 probably was a cysteine residue SH. Mercury compounds can be assayed amperometrically with the detection limits 0.1 ng ml(-1) Hg for HgCl2 and methylmercury, 0.2 ng ml(-1) Hg for Hg2(NO3)2 and 1.7 ng ml(-1) Hg for mercury glutathione complex. Inactivation of the immobilized horseradish peroxidase was displayed in the AFM images of the enzyme membranes.
Han
S
S
Department of Chemistry, Graduate School, University of Science and Technology of China, Chinese Academy of Sciences, Beijing, People's Republic of China.
Zhu
M
M
Yuan
Z
Z
Li
X
X
D015374:Biosensing Techniques; D005978:Glutathione / Q000032:analysis / Q000737:chemistry; D008628:Mercury / Q000032:analysis* / Q000737:chemistry; D008751:Methylene Blue; D008767:Methylmercury Compounds / Q000032:analysis* / Q000737:chemistry
D008767:Methylmercury Compounds; D008628:Mercury; D005978:Glutathione; D008751:Methylene Blue