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ANANBIOANAL - 2010
Pharmaceutical R & D Summit
doi:10.4172/2155-9872.1000095
Electrochemical Biosensor for Detection of Cadmium in Milk
Sachin Suryan, Neelam Verma and Hardeep Kaur
Punjabi University, Department of Biotechnology, Patiala, India
E
xposure to cadmium is among the main threats to human health from heavy
metals. Among heavy metals cadmium and lead are the main contaminant of
milk (Alonso et al., 2003, Ayar et al., 2008). The permissible limit of Cd in milk
has not been defined though it is 3 ppb for mineral water as defined in CODEX
STAN 193-1995 rev.2009. In the present study an electrochemical biosensor has
been developed for the detection cadmium in milk. Bacillus badius whole cells,
an isolate of biosensor technology lab, were used as biocomponent in the study,
immobilized at the tip of carbon paste electrode. The principle of biosensor was
based on the inhibition of urease activity, was measured in terms of NADPH through
cyclic voltammetry at a scan rate of 100mV/s. Bacillus badius is a urease producing
micro-organism; urease and Glutamate dehydrogenase of the cell were used as bi-
enzymatic machinery in the assay. Ammonium ion produced by urease activity along
with NADPH was utilized in the reaction catalyzed by Glutamate dehydrogenase.
Excess of NADPH was measured through cyclic voltammetry. Inhibition of urease
leads to lesser production of ammonium ion thereby increase in unutilized NADPH
and therefore increases the current. The developed biosensor was applied to
natural milk and spiked milk samples. A detection limit of as low as 0.5ppb has been
achieved. Cadmium is showing specificity over lead there is no interference of lead.
Application of whole cells in the study as bi-enzymatic machinery is making the
practice cost effective.
ANALBIOANAL-2010
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