An optical fiber caffeine sensor using a molecularly imprinted polymethacrylic acid membrane coated on optical fiber surface as a transducer.

Caffeine is a neurotransmitter, important to human health. This compound exists in many food products, has been added to soft drinks, pharmaceutical drugs. For many applications, a field deployable technique for quick detecting caffeine is attractive. In this paper, we report a selective optical fiber caffeine sensor using a molecularly imprinted polymer (MIP) membrane as a transducer. The membrane extracts/concentrate caffeine from sample solutions significantly improved sensor's sensitivity with a 95 times sensitivity improvement. The sensor achieved a detection limit of 2.0 μg/mL. This sensor was used to directly analyze caffeine in soft drink products without interference from sample matrix.