“…Biosensors can be categorized according to their transducer: potentiometric (Ion-Selective Electrodes (ISEs), Ion-Sensitive Field Effect Transistors (ISFETs)), amperometric, conductometric, impediometric, calorimetric, optical and piezoelectric. FA selective biosensors are based on cells (Korpan et al, 1993) or enzymes used as biorecognition elements: either alcohol oxidase (AOX) (Korpan et al, 1997(Korpan et al, , 2000Dzyadevych et al, 2001) or formaldehyde dehydrogenase (FdDH) (Herschkovitz et al, 2000;Kataky et al, 2002, Achmann et al, 2008. A number of sensor approaches for the detection of FA concentration have been published including systems operating in gas (Dennison et al, 1996;Hämmerle et al, 1996;Vianello et al, 1996) and organic phases.…”