Sensitive indoor air monitoring of formaldehyde and other carbonyl compounds using the 2,4-dinitrophenylhydrazine method

The toxic potential of formaldehyde and other aliphatic/aromatic carbonyl compounds requires the determination of even low amounts of these compounds in indoor air. The existing DFG-method for workplace monitoring using adsorption at 2,4-dinitrophenylhydrazine (DNPH)-coated sorbents followed by HPLC-UV/DAD analysis of the extract was modified in order to decrease detection limits. The improvement included an increase in volume and rate of the air sampling, testing applicability of different adsorption materials and a decrease of the extraction volume of the hydrazones. 13 DNPH-derivatives could be separated well on a RP18-column followed by UV/DAD-detection at 365 nm. Recovery rates of 70-100 % were determined (apart from acetone with 19 %) using dynamically produced artificial carbonyl atmospheres. Detection limits of 0.05-0.4 mug/m(3) were reached by this method which are sufficient for indoor air monitoring.