| 1. |
- CAGNINI, A, et al.
(författare)
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DISPOSABLE RUTHENIZED SCREEN-PRINTED BIOSENSORS FOR PESTICIDES MONITORING
- 1995
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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier Science B.V., Amsterdam.. - 0925-4005 .- 1873-3077. ; 24:03-jan, s. 85-89
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Tidskriftsartikel (refereegranskat)abstract
- A disposable choline biosensor based on ruthenized carbon screen-printed electrodes has been prepared and its use for monitoring organophosphorus pesticides and carbamates is described. The presence of 0.5% ruthenium on activated carbon mixed to form a simple graphite-based ink for the working electrode surface increased the sensitivity towards hydrogen peroxide. The choline biosensor is based on such an electrode coupled with choline oxidase immobilized by adsorption. The inhibition effect of carbamates and organophosphorus pesticides on acetylcholinesterase was detected using this biosensor. With the optimized procedure described (pH, buffer composition, incubation time, substrate concentration) we are able to detect concentrations of pesticides (carbofuran) as low as 1 nM.
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| 2. |
- Cagnini, A, et al.
(författare)
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Ruthenized screen-printed choline oxidase-based biosensors for measurement of anticholinesterase activity
- 1995
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Ingår i: Microchimica Acta. - : Springer Science Business Media. - 0026-3672 .- 1436-5073. ; 121:04-jan, s. 155-166
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Tidskriftsartikel (refereegranskat)abstract
- Plastic disposable choline biosensors based on ruthenized-carbon screen-printed electrodes were prepared and their use for monitoring organophosphorus pesticides and carbamates is described. The presence of 0.5% ruthenium on activated carbon mixed to form a simple graphite-based ink for the working electrode surface increased the sensitivity towards hydrogen peroxide. The choline biosensor is based on such an electrode coupled with choline oxidase immobilized by adsorption and was used to detect the inhibition effect of carbamates and organophosphorus pesticides on acetylcholinesterase. With the optimized procedure described (pH, buffer composition, incubation time, substrate concentration), concentrations of pesticides (Carbofuran) as low as 1 nM could be detected.
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| 3. |
- Palchetti, I, et al.
(författare)
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Characterisation of screen-printed electrodes for detection of heavy metals
- 1999
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Ingår i: Microchimica Acta. - : Springer Science Business Media. - 0026-3672 .- 1436-5073. ; 131:02-jan, s. 65-73
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Tidskriftsartikel (refereegranskat)abstract
- The characterisation of disposable screen-printed electrodes for stripping analysis is described. The graphite surface of the working electrode is used as substrate for plating a thin mercury film, which allows the electrochemical preconcentration of heavy metals. Optimisation procedures and experimental results are presented. Detection limits around the ppb level were obtained for different metals [Pb(II), Cd(II), Cu(II)].
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| 4. |
- Palchetti, I, et al.
(författare)
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Determination of anticholinesterase pesticides in real samples using a disposable biosensor
- 1997
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Ingår i: Analytica Chimica Acta. - : Elsevier Science B.V., Amsterdam.. - 0003-2670 .- 1873-4324. ; 337:3, s. 315-321
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Tidskriftsartikel (refereegranskat)abstract
- A choline amperometric biosensor based on screen-printed electrodes was assembled and used to assess the inhibitory effect of organophosphorus and carbamic pesticides on acetylcholinesterase activity both in standard solutions and real samples, Acetylcholinesterase catalyses the cleavage of acetylcholine to choline and acetate, therefore the amount of choline measured using the biosensor is directly related to the enzyme activity. The extent of enzyme inhibition can be used as an index of the amount of anticholinesterase pesticides present. The hydrophobicity of organophosphorus and carbamic pesticides led to the evaluation of organic, water miscible solvents for use in the proposed method. Berate buffer containing 1% v/v acetonitrile was selected since it exhibited the least influence on enzyme activity from the tested solvents (acetonitrile, acetone, tetrahydrofuran and ethylacetate). Other solvents (dimethylsulfoxide and methanol) were avoided as they exhibited electrochemical interferences. An inhibition calibration curve was obtained using carbofuran, a strong inhibitor of acetylcholinesterase. The lowest detectable standard solution (mean +/-3 standard deviation of the blank) was 2 mu gl(-1) following an incubation time of 10 min. The method was then applied to real samples (fruits and vegetables) showing its suitability as a rapid screening assay (12 min per test) for the assessment of anticholinesterase pesticides, The biosensor results were compared with a standard analytical technique (gas chromatography with nitrogen phosphorus detector, GC-NPD).
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