doi:10.1038/nindia.2012.56 Published online 20 April 2012
Researchers have designed a new type of biosensor that can detect minute traces of vitamin B12 in energy drinks. This will be useful for monitoring the levels of vitamin B12 in pharmaceutical and commercial food samples.
Excessive consumption of vitamin B12 may cause asthma and folic acid deficiency. So there is a need to monitor vitamin B12 levels in pharmaceutical and food samples.
Existing chromatographic techniques are expensive and time-consuming. To devise a cheap and simple biosensor, the researchers produced vitamin B12 antibodies using hen egg yolk proteins and coated them on strips of nitrocellulose membrane. They dipped these antibody-coated strips in separate solutions of free vitamin B12 and vitamin B12 conjugated to alkaline phosphatase. They also dipped some strips in a solution containing an organic compound that exhibits chemiluminescence. The researchers tested the efficacy of the biosensor using two commercial energy drinks containing vitamin B12.
The chemiluminescence-generating organic compound reacted only with vitamin B12 conjugated to alkaline phosphatase, yielding a meta-stable anion that decomposed to emit a chemiluminescence signal. The signal was inversely proportional to the concentration of vitamin B12 in the sample.
The biosensor's limit of detection was 1 ng/ml. "This technique can also be applied to detect contaminants and hazardous materials in food and environment samples," says lead researcher M. S. Thakur.