Author/Authors :
Abdullah، Jaafar نويسنده Industrial Biotechnology Research Centre, Sirim Berhad, 1 Persiaran Dato’ Menteri, P.O. Box 7035, 40911 Shah Alam, Selangor, Malaysia , , Rahman، Samsulida Abd نويسنده Industrial Biotechnology Research Centre, Sirim Berhad, 1 Persiaran Dato’ Menteri, P.O. Box 7035, 40911 Shah Alam, Selangor, Malaysia , , Sidek ، Hamidah نويسنده Industrial Biotechnology Research Centre, Sirim Berhad, 1 Persiaran Dato’ Menteri, P.O. Box 7035, 40911 Shah Alam, Selangor, Malaysia , , Azmi، Nur Ellina نويسنده Industrial Biotechnology Research Centre, Sirim Berhad, 1 Persiaran Dato’ Menteri, P.O. Box 7035, 40911 Shah Alam, Selangor, Malaysia ,
Abstract :
A mediated amperometric biosensor based on bi-layer glutamate dehydrogenase
(GLDH)/diaphorase immobilized on screen printed carbon paste electrode (SPCE) for the
determination of ammonium has been described. In this work the electrochemical oxidation
of NADH was used as indicator reaction for the quantification of ammonium concentration.
The use of ferrocene carboxaldehyde as an electron transfer mediator lowered the oxidation
potential of NADH to +0.4 V vs. Ag/AgCl. Parameter optimization improves the analytical
performance of the biosensor within the linearity range of 2.5 ?M to 500 ?M with the
detection limit of 2.5 ?M. The reproducibility of the fabricated biosensor was also evaluated
and it was found to be good with a relative standard deviation (RSD) of 4.17% (n=5). A good
agreement with the Indothymol method was obtained for the measurement of ammonium in
water samples.
