A NEW TECHNIQUE FOR COLLECTION, CONCENTRATION AND DETERMINATION OF GASEOUS TROPOSPHERIC FORMALDEHYDE

This article describes an improved technique for making in situ measurements of gaseous tropospheric formaldehyde (CH//2O). The new technique is based on nebulization/reflux principles that have proved very effective in quantitatively scrubbing water soluble trace gases (e. g. CH//2O) into aqueous mediums, which are subsequently analyzed. Atmospheric formaldehyde extractions and analysis have been performed with the nebulization/reflux concentrator using an acidified dinitrophenylhydrazine solution that indicate that quantitative analysis of CH//2O at global background levels (approx. 0. 1 ppbv) is feasible with 20-min extractions. Analysis of CH//2O, once concentrated, is accomplished using high performance liquid chromatography (HPLC) with ultraviolet photometric detection. The CH//2O-hydrazone derivative, produced by the reaction of 2,4-dinitrophenylhydrazine in H//2SO//4 acidified aqueous solution, is detected as CH//2O.