Time-resolved absorption as optical method for herbicide detection

A new sensing system for the detection of photosynthetic herbicides in water has been developed, based on the use of a trans-membrane protein complex, the reaction centre (RC) isolated from Rhodobacter sphaeroides. The stationary and excited state of this protein are characterised by different absorption properties. The path followed by the protein to return to the stationary state is influenced by the presence of photosynthetic herbicides. Therefore the concentration of herbicides could be measured by monitoring the temporal changes of absorption following optical excitation. For this purpose, an optoelectronic system has been realised. It makes use of a 860 nm light emitting diode and a hybrid photodetector and is coupled to a 5 cm-long optical cell containing the RC solution through optical fibres. The system was tested with atrazine and a limit of detection of 10 nM was obtained.

[1]  James S. Wilkinson,et al.  Integrated optical Mach-Zehnder interferometers as simazine immunoprobes , 1997 .

[2]  K. Buchel.  Chemistry of pesticides. , 1983 .

[3]  Otto S. Wolfbeis,et al.  Fiber-optic remote detection of pesticides and related inhibitors of the enzyme acetylcholine esterase☆ , 1993 .

[4]  A. Ezhov,et al.  Chemiluminescent multiassay of pesticides with horseradish peroxidase as a label. , 1999, Biosensors & bioelectronics.

[5]  Andreas Brecht,et al.  A direct optical immunosensor for atrazine detection , 1995 .

[6]  G. Feher,et al.  Direct Charge Recombination from D+QAQB- to DQAQB in Bacterial Reaction Centers from Rhodobacter sphaeroides , 1994 .

[7]  F. Baldini,et al.  Fiber optic monitoring of carbamate pesticides using porous glass with covalently bound chlorophenol red. , 2000, Biosensors & bioelectronics.

[8]  Rolf D. Schmid,et al.  Herbicide biosensor based on photobleacing of the reaction centre of Rhodobacter sphaeroides , 1993 .

[9]  Maria Minunni,et al.  Detection of Pesticide in Drinking Water Using Real-Time Biospecific Interaction Analysis (BIA) , 1993 .

[10]  B. Luff,et al.  Integrated optical surface plasmon resonance immunoprobe for simazine detection. , 1999, Biosensors & bioelectronics.

[11]  C. Barzen,et al.  Optical multiple-analyte immunosensor for water pollution control. , 2002, Biosensors & bioelectronics.

[12]  K Schulten,et al.  Architecture and mechanism of the light-harvesting apparatus of purple bacteria. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[13]  Günter Gauglitz,et al.  Label-free parallel screening of combinatorial triazine libraries using reflectometric interference spectroscopy. , 2002, Analytical chemistry.

[14]  Joshua Jortner,et al.  Unidirectionality of charge separation in reaction centers of photosynthetic bacteria , 1988 .

[15]  H. M. Widmer,et al.  Fiber-optic Atrazine immunosensor☆ , 1993 .

[16]  J Deisenhofer,et al.  X-ray structure analysis of a membrane protein complex. Electron density map at 3 A resolution and a model of the chromophores of the photosynthetic reaction center from Rhodopseudomonas viridis. , 1984, Journal of molecular biology.

[17]  R Narayanaswamy,et al.  Fibre-optic pesticide biosensor based on covalently immobilized acetylcholinesterase and thymol blue. , 1997, Talanta: The International Journal of Pure and Applied Analytical Chemistry.