Author/Authors :
Raghu، Pamula نويسنده Electrochemical Research Laboratory, Department of Chemistry, S.V.U. College of Sciences, Sri Venkateswara University, Tirupati – 517 502, Andhra Pra , , Mohan Reddy، Matti R. نويسنده Department of Psychiatry, Sri Devaraj Urs Acedamy of Higher Education and Research (SDUAHER), Tamaka, Kolar, Karnataka, India , , Reddy، Tukiakula Madhusudana نويسنده Electrochemical Research Laboratory, Department of Chemistry, S.V.U. College of Sciences, Sri Venkateswara University, Tirupati – 517 502, Andhra Pra , , Kumara Swamy، Bahaddurghatta E. نويسنده Department of P.G. Studies and Research in Industrial Chemistry, Kuvempu University, Jnana Sahyadri, Shankaraghatta, Shimoga, Karnataka 577451, India , , Reddaiah، Kasetty نويسنده Electrochemical Research Laboratory, Department of Chemistry, S.V.U. College of Sciences, Sri Venkateswara University, Tirupati – 517 502, Andhra Pra ,
Abstract :
Acetylcholinesterase (AChE) enzyme was immobilized through the silica sol–gel
process onto the surface of carbon paste electrode (CPE). This fabricated monoenzyme
biosensor on CPE was used as a working electrode. The enzyme biosensor on reaction with
acetylthiocholine chloride (ASChCl or substrate), was found to be enzymatically hydrolyzed
to thiocholine and acetic acid, which intern gave a disulfide compound and produced a larger
anodic current at 0.63 V. The AChE biosensor was used for determining the two
organophosphorous pesticides i.e. quinalphos and malathion in 0.1 M phosphate buffer/0.1 M
KCl. The effect of scan rate, pH, enzyme loading and substrate concentration on the
biosensor response was studied. Calibration graphs were performed for a concentration range
of 20–300 ppb and 0.07–1.3 ppm for quinalphos and malathion respectively by employing
the fabricated biosensor electrode. The limit of detection and limit of quantification values
was found to be 8 ppb, 0.058 ppm and 26 ppb, 0.194 ppm for quinalphos and malathion
respectively.
