Amperometric biosensor for formic acid in air

The possibility of developing a simple, inexpensive and specific personal passive ”real-time” air sampler based on biosensor technology was investigated. Formic acid was used as a model substance. The sensor is based on the enzymatic reaction between formic acid and formate dehydrogenase with NAD+ as a cofactor and Meldola’s blue as mediator. An effective way to immobilise the enzyme, cofactor and Meldola’s blue on screen-printed electrodes was found to be in a mixture of glycerol and phosphate buffer covered with a gas-permeable membrane. When the sensor was introduced into an atmosphere containing formic acid, it gave a distinct and rapid amperometric response.