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) was an important cholinesterase enzyme present in
the living organisms, which is responsible for transmission of impulses through synaptic
clefts by oxidation of acetylcholine to choline. Acetylcholinesterase enzyme was
immobilized through silica sol–gel process on the surface of carbon paste electrode which
was used to fabricate monoenzyme biosensor. It is a rapid, simple and sensitive biosensor
used for determination of two organophosphorous pesticides monocrotophos and
phosphamidon in 0.1 M phosphate buffer and in 0.1 M KCl. Acetylthiocholine chloride
(ASChCl) was used as substrate by enzymatic hydrolysis it gives thiocholine which
undergone electrochemical oxidation and produces anodic current around at 0.60 V vs.
saturated calomel electrode. The effect of scan rate, pH, enzyme loading and substrate
concentration on the biosensor response was studied. The biosensor provided a high
sensitivity, large linear concentration range from 50–900 ppb, 0.1–1.25 ppm for
monocrotophos and phosphamidon. The detection limits were found to be 45 ppb, 0.06 ppm
for monocrotophos and phosphamidon respectively. The results showed the optimum
conditions for pH, substrate concentration, and incubation time were at room temperature, pH
7.0, 1 mM, 4 and 3 min for monocrotophos and phosphamidon respectively.
