Determination of formaldehyde and acetaldehyde in air by HPLC with fluorescence detection

Sensitive detection of atmospheric formaldehyde and acetaldehyde can be achieved by use of silica-gel cartridges impregnated with 2-diphenylacetyl-1,3-indandione-1-hydrazone (DAIH) to form fluorescent DAI hydrazones. The hydrazones are extracted with acetonitrile and separated by reversed-phase HPLC with fluorimetric detection. The low detection limits achieved (0.25 ppb CH2O or CH3CHO for sampling periods of 1 h) means that the sensitivity of the method is better than that of the classical dinitrophenylhydrazine (DNPH) method. Several experimental conditions, such as collection and reaction efficiency, interference by ozone and storage stability of blank and sampled cartridges have been investigated. There were no significant differences between ambient concentrations of CH2O and CH3CHO measured concurrently with the DAIH and DNPH techniques (10–20% in the 0–5 ppb range).