University of North Florida
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Contact Info

Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Email: schalk@unf.edu
Website: @unf

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Mladen Franko

Abbrev:
Franko, M.
Other Names:
Address:
School of Environmental Sciences, Nova Gorica Polytechnic, P.O. Box 301, 5001 Nova Gorica, Slovenia
Phone:
+386-65-125295
Fax:
+386-65-125296

Citations 3

"Optimisation Of FIA System For Detection Of Organophosphorus And Carbamate Pesticides Based On Cholinesterase Inhibition"
Talanta 2001 Volume 54, Issue 4 Pages 631-641
Lea Pogačnik and Mladen Franko

Abstract: The sensitivity of the bioanalytical FIA system containing different immobilized cholinesterases (AChEs from electric eel, human erythrocytes, bovine erythrocytes and BuChE from horse serum) for determination of organophosphorus and carbamate pesticides was tested. Responses to some frequently used organophosphorus (paraoxon. oxydemeton-methyl. triazophos) and carbamate (carbofuran. propoxur) pesticides were found to be dependent on the origin of cholinesterases. The highest sensitivity was obtained by bioanalytical columns prepared with electric eel AChE while the lowest sensitivity was shown by the bioanalytical columns prepared with horst serum BuChE. The differences in responses for different enzymes were found to be less pronounced when the contact time between the enzyme and the pesticide is long enough (low flow rates). The optimal flow rate was chosen as a compromise between the duration of analysis and reasonably low limits of detection. (C) 2001 Elsevier Science B.V. All rights reserved.

"Determination Of Organophosphate And Carbamate Pesticides In Spiked Samples Of Tap Water And Fruit Juices By A Biosensor With Photothermal Detection"
Biosens. Bioelectron. 1999 Volume 14, Issue 6 Pages 569-578
Lea Pogačnik and Mladen Franko

Abstract: The determination of organophosphate (paraoxon, chlorpyrifos, diazinon) and carbamate (carbaryl, carbofuran) pesticides in spiked drinking water and fruit juices was carried out using a photothermal biosensor. The biosensor consists of a cartridge containing immobilized enzyme acetylcholinesterase (AChE) placed in a flow injection analysis (FIA) manifold and a photothermal detector based on thermal lens spectrometry. With this approach, 0.2 ng/ml of paraoxon can be detected in less than 15 min. Limits of detection for other organophosphate (chlorpyrifos, diazinon) and carbamate (carbaryl, carbofuran) pesticides varied, depending on their antiacetylcholinesterase (AntiAChE) toxicity, from 1 ng/ml to 4 µg/mL. The biosensor was used for the direct detection of pesticides in spiked tap water and fruit juices without any pretreatment steps. In these cases, the LOD (3s) of 1.5, 2.8 and 4 ng/ml paraoxon in tap water, orange juice and apple juice were obtained, respectively.
Enzyme

"Validation Of Different Commercially Available Cholinesterases For Pesticide Toxicity Test"
Ann. Chim. 2002 Volume 92, Issue 1-2 Pages 93-101
L. Pogacnik and M. Franko

Abstract: A systematic study of different commercially available cholinesterases (AChEs from electric eel, human erythrocytes, bovine erythrocytes and BuChE from horse serum) for the FIA determination of some frequently used organophosphate (paraoxon, oxydemeton-methyl, triazophos, diazionon) and carbamate (carbofuran, propoxur) pesticides was carried out. Responses of the previously developed photothermal FIA system were found to be dependent on the origin of cholinesterases and proper-ties of tested pesticides. The highest sensitivity was obtained with electric eel AChE and the lowest sensitivity with horse serum BuChE. The LOD values for investigated pesticides correlate with acute toxicities expressed as LD50 (oral, rat), The presented FIA system could serve as an alternative screening test to evaluate the toxicity of different environmental samples, new cholinesterase inhibiting pesticides or other products (e.g. nerve gases).