Analytical Sciences

Highly Sensitive Detection of Bensulfuron-methyl by Time-Resolved Fluoroimmunoassay Using a Tetradentate β-Diketonate Europium Chelate as a Label

Jingli YUAN*1, *2 , Guilan WANG*1, *2 , Hiroko KIMURA*2, *3 and Kazuko MATSUMOTO*1, *2*

*1 Department of Chemistry, Waseda University, Shinjuku, Tokyo 169-8555, Japan
*2 Japan Science and Technology Corporation (JST)
*3 Department of Forensic Medicine, Juntendo University School of Medicine, Bunkyo, Tokyo 113-8421, Japan

A tetradentate b-diketonate europium fluorescent chelate, 4,4'-bis(1",1",1",2",2",3",3"-heptafluoro-4",6"-hexanedion-6"-yl)-chlorosulfo-o-terphenyl (BHHCT)-Eu³⁺, was used as a label for highly sensitive time-resolved fluoroimmunoassay of bensulfuron-methyl (BSM). A BSM-BSA (BSA=bovine serum albumin) conjugate was labeled with BHHCT-Eu³⁺ and the labeled BSM-BSA conjugate was used for competitive immunoassay. The assay was carried out in a 96-well microtiter plate coated with the anti-BSM monoclonal antibody. The method gives the detection limit of 24 pg/ml, which is one to two orders of magnitude lower than those of the conventional HPLC and other methods. The RSD of the present method is less than 10%, and the recovery is in the range of 90 - 110% for BSM water samples. (Keywords: Time-resolved fluoroimmunoassay, bensulfuron-methyl, europium fluorescent chelate)

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