ELECTROCHEMICAL DETECTION OF ORGANIC GASES - THE DEVELOPMENT OF A FORMALDEHYDE SENSOR

Using differential electrochemical mass spectrometry, we determined the amount of H2-evolution occuring during formaldehyde oxidation as a function in the potential region of the first oxidation wave. In the second wave, the oxidation product is CO2 in pH 8 solution, as opposed to more alkaline solutions where only formiate is formed. Formaldehyde is reduced to methanol at potentials negative of the RHE. An electrochemical formaldehyde sensor was built with a sensitivity below 1 ppm. Cross sensitivities towards alcohols can be lowered by UPD of Ag or Hg.