title: Conductometric tyrosinase biosensor for the detection of diuron, atrazine and its main metabolites.
abstract: The determination of diuron, atrazine, desisopropylatrazine (DIA) and desethylatrazine (DEA) were investigated using conductometric tyrosinase biosensor. Tyrosinase was immobilised on the biosensor sensitive part by allowing it to mix with bovine serum albumin (BSA) and then cross-linking in saturated glutaraldehyde (GA) vapour for 30min. The determination of pollutants in a solution was performed by comparison of the output signal (i.e percentage of the enzymatic activity) of the biosensor before and after contact with pollutants. The measurement of the enzymatic activity was performed using 4-chlorophenol, phenol and catechol substrates and response times ranging from 1 to 5min were observed. A 4-chlorophenol substrate was used to detect pesticides. A 30min contact time of the biosensor in the pollutant solution was used. Under the experimental conditions employed, detection limits for diuron and atrazine were about 1ppb and dynamic range of 2.3-2330 and 2.15-2150ppb were obtained for diuron and atrazine, respectively. A relative standard deviation (n=3) of the output signal was estimated to be 5% and a slight drift of 1.5muSh(-1) was observed. The 90% of the enzyme activity was still maintained after 23 days of storage in a buffer solution at 4 degrees C.
authors.affiliation: Laboratoire d'Application de la Chimie à l'Environnement, UMR CNRS 5634, Université Claude Bernard Lyon I, 43 Boulevard du 11 Novemvre 1918, Villeurbanne Cedex 69622, France; International Training Institute for Materials Science (ITIMS), Hanoi University of Technology, 1 Dai Co Viet, Hanoi, Viet Nam.
authors.forename: Tuan Mai
authors.initials: TM
authors.lastname: Anh
authors.forename: Sergei V
authors.initials: SV
authors.lastname: Dzyadevych
authors.forename: Minh Chau
authors.initials: MC
authors.lastname: Van
authors.forename: Nicole Jaffrezic
authors.initials: NJ
authors.lastname: Renault
authors.forename: Chien Nguyen
authors.initials: CN
authors.lastname: Duc
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Chovelon