Preconcentration with membrane cell and adsorptive polarographic determination of formaldehyde in air

The present paper describes a procedure that formaldehyde in air was preconcentrated in a membrane cell and its content was determined by adsorptive polarography. First the formaldehyde in air samples was preconcentrated in a membrane cell using water, then the formaldehyde reacted with 2,4-dinitrophenyl hydrazine to form 2,4-dinitrophenyl hydrazone, which can be adsorbed at the mercury electrode and yields a sensitive adsorptive polarographic wave. Over the range 6.0×10−10–5.0×10−6 M, the peak currents are linearly proportional to the concentration of formaldehyde, the detection limit is 2.0×10−10 M.