Detection of pesticides using an amperometric biosensor based on ferophthalocyanine chemically modified carbon paste electrode and immobilized bienzymatic system.
A new highly sensitive amperometric method for the detection of organophosphorus compounds has been developed. The method is based on a ferophthalocyanine chemically modified carbon paste electrode coupled with acetylcholinesterase and choline oxidase co-immobilized onto the surface of a dialysis membrane. The activity of cholinesterase is non-competitively inhibited in the presence of pesticides. The highest sensitivity to inhibitors was found for a membrane containing low enzyme loading and this was subsequently used for the construction of an amperometric biosensor for pesticides. Analyses were done using acetylcholine as substrate; choline produced by hydrolysis in the enzymatic layer was oxidized by choline-oxidase and subsequently H(2)O(2) produced was electrochemically detected at +0.35 V vs. Ag/AgCl. The decrease of substrate steady-state current caused by the addition of pesticide was used for evaluation. With this approach, up to 10(-10) M of paraoxon and carbofuran can be detected.
Ciucu
Anton A
AA
Department of Analytical Chemistry, Faculty of Chemistry, University of Bucharest, 90-92 Panduri Avenve, Bucharest, Romania. anton@chem.unibuc.ro
Negulescu
Carmela
C
Baldwin
Richard P
RP
D000110:Acetylcholinesterase; D000429:Alcohol Oxidoreductases; D000448:Aldicarb / Q000032:analysis; D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D002235:Carbofuran / Q000032:analysis; D002244:Carbon / Q000737:chemistry*; D002417:Cattle; D020099:Coated Materials, Biocompatible / Q000138:chemical synthesis; D003067:Coenzymes; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods; D004593:Electrophorus; D004912:Erythrocytes / Q000737:chemistry / Q000201:enzymology; D007211:Indoles / Q000737:chemistry; D008567:Membranes, Artificial; D009824:Ointments; D009942:Organometallic Compounds / Q000737:chemistry; D010261:Paraoxon / Q000032:analysis; D010575:Pesticides / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D020099:Coated Materials, Biocompatible; D003067:Coenzymes; D007211:Indoles; D008567:Membranes, Artificial; D009824:Ointments; D009942:Organometallic Compounds; D010575:Pesticides; C056691:ferrous phthalocyanine; D002244:Carbon; D000448:Aldicarb; D000429:Alcohol Oxidoreductases; C019888:choline oxidase; D000110:Acetylcholinesterase; D010261:Paraoxon; D002235:Carbofuran