title: Molinate quantification in environmental water by a glutathione-S-transferase based biosensor.
abstract: A glutathione-S-transferase (GST) based biosensor was developed to quantify the thiocarbamate herbicide molinate in environmental water. The biosensor construction was based on GST immobilization onto a glassy carbon electrode via aminosilane-glutaraldehyde covalent attachment. The principle supporting the use of this biosensor consists of the GST inhibition process promoted by molinate. Differential pulse voltammetry was used to obtain a calibration curve for molinate concentration, ranging from 0.19 to 7.9 mg L(-1) and presenting a detection limit of 0.064 mg L(-1). The developed biosensor is stable, and reusable during 15 days. The GST-based biosensor was successfully applied to quantify molinate in rice paddy field floodwater samples. The results achieved with the developed biosensor were in accordance with those obtained by high performance liquid chromatography. The proposed device is suitable for screening environmental water analysis and, since no sample preparation is required, it can be used in situ and in real-time measurements.
authors.affiliation: REQUIMTE, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Rua Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal.
authors.forename: Túlio I S
authors.initials: TI
authors.lastname: Oliveira
authors.forename: Marcela
authors.initials: M
authors.lastname: Oliveira
authors.forename: Subramanian
authors.initials: S
authors.lastname: Viswanathan
authors.forename: M
authors.initials: M
authors.lastname: Fátima Barroso
authors.forename: Luísa
authors.initials: L
authors.lastname: Barreiros
authors.forename: Olga C
authors.initials: OC
authors.lastname: Nunes
authors.forename: José A
authors.initials: JA
authors.lastname: Rodrigues
authors.forename: Pedro
authors.initials: P
authors.lastname: de Lima-Neto
authors.forename: Selma E
authors.initials: SE
authors.lastname: Mazzetto
authors.forename: Simone
authors.initials: S
authors.lastname: Morais
authors.forename: Cristina
authors.initials: C
authors.lastname: Delerue-Matos
mesh_terms: D001381:Azepines / Q000032:analysis*; D015374:Biosensing Techniques / Q000379:methods / Q000592:standards; D002138:Calibration; D002244:Carbon; D003432:Cross-Linking Reagents / Q000737:chemistry; D055664:Electrochemical Techniques; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry*; D017743:Equipment Reuse; D005978:Glutathione / Q000737:chemistry; D005982:Glutathione Transferase / Q000737:chemistry*; D006540:Herbicides / Q000032:analysis*; D006801:Humans; D013859:Thiocarbamates / Q000032:analysis*; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D001381:Azepines; D003432:Cross-Linking Reagents; D004800:Enzymes, Immobilized; D006540:Herbicides; D013859:Thiocarbamates; D014874:Water Pollutants, Chemical; D014867:Water; C009821:molinate; D002244:Carbon; D005982:Glutathione Transferase; D005978:Glutathione