Release Time:2019-03-09  Hits:

Indexed by: Journal Article

Date of Publication: 2014-08-01

Journal: INTERNATIONAL JOURNAL OF ENVIRONMENTAL ANALYTICAL CHEMISTRY

Included Journals: EI、SCIE

Volume: 94

Issue: 10

Page Number: 988-1000

ISSN: 0306-7319

Key Words: carbon nanotube; DNAzyme; Microcystin-LR; electrochemical immunoassay

Abstract: An electrochemical immunoassay for microcystin-LR (MC-LR) detection was developed using multi-labeled horseradish peroxidase-mimicking DNAzyme on carbon nanotubes (CNTs) as electrocatalyst for signal amplification. CNTs were covalently conjugated to multiple DNAzyme along with MC-LR for a competitive immunoassay. The as-prepared DNAzyme/CNTs/MC-LR biolabel was specifically captured on the electrode surface, and current responses were obtained upon the electro-catalytic reduction of hydrogen peroxide by the captured biolabels. Under optimal conditions, the electro-catalytic current decreased linearly with the increase amount of MC-LR in the range from 0.01 to 7.0 mu g L-1. The linear regression equation was I (mu A) = 12.96 - 1.48 X ([MC-LR]) (mu g L-1), with a correlation coefficient of 0.989. The limit of detection of MC-LR was 2.31 ng L-1. Application of the immunoassay method and LC/MS/MS method for MC-LR determination on spiked reservoir water gave recovery range of 91.7-105.2% and 94.0-105.0%, respectively. The resulting versatile immunoassay exhibited high sensitivity, good precision and satisfactory reproducibility, which could have vast potential in routine water quality monitoring for various environmental toxins.