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.
Department of Chemistry, Graduate School, University of Science and Technology of China, Chinese Academy of Sciences, Beijing, People's Republic of China.
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Han
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Zhu
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Yuan
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Li
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