A new bacterial biosensor for trichloroethylene detection based on a three-dimensional carbon nanotubes bioarchitecture
Résumé
Trichloroethylene (TCE), a suspected human carcinogen, is one of the most common volatile groundwater contaminants. Many different methodologies have already been developed for the determination of TCE and its degradation products in water, but most of them are costly, time-consuming and require well-trained operators. In this work, a fast, sensitive and miniaturised whole cell conductometric biosensor was developed for the determination of trichloroethylene. The biosensor assembly was prepared by immobilising Pseudomonas putida F1 bacteria (PpF1) at the surface of gold interdigitated microelectrodes through a three-dimensional alkanethiol self-assembly monolayer/carbon nanotube architecture functionalised with Pseudomonas antibodies. The biosensor response was linear from 0.07 to 100 mu M of TCE (9-13,100 mu g L(-1)). No significant loss of the enzymatic activity was observed after 5 weeks of storage at 4 A degrees C in the M457 pH 7 defined medium (two or three measurements per week). Ninety-two per cent of the initial signal still remained after 7 weeks. The biosensor response to TCE was not significantly affected by cis-1,2-dichloroethylene and vinyl chloride and, in a limited way, by phenol. Toluene was the major interference found. The bacterial biosensor was successfully applied to the determination of TCE in spiked groundwater samples and in six water samples collected in an urban industrial site contaminated with TCE. Gas chromatography-mass spectrometric analysis of these samples confirmed the biosensor measurements.
Mots clés
Trichloroethylene
Whole cell biosensor
Pseudomonas putida F1
Interdigitated microelectrodes
Single-wall carbon nanotubes
Self-assembly monolayer
SELF-ASSEMBLED MONOLAYERS
PSEUDOMONAS-PUTIDA F1
TOLUENE DIOXYGENASE
WHOLE-CELL
IMMOBILIZATION METHOD
MICROBIAL BIOSENSORS
TRICHLOROACETIC-ACID
DICHLOROACETIC ACID
DEGRADATION
SENSOR