Measurement of Aldehydes Using DNPH Derivatization and WaterImpinger Methods

摘要

Determination of aldehydes in ambient air as well as industrial stacks is receiving increasedattention because of the critical role these compounds play in tropospheric organic chemistry;including ozone formation and photochemical smog. Aldehydes and ketones are sampled usingDNPH derivatization methods (EPA 0011, TO-11A, and CARB 430) as well as water impingermethods (NCASI 99.02). The acrolein chemistry associated with derivatization is complexbecause of the tautomerization of its hydrazone in acidified DNPH solution. In thisinvestigation, the problems associated with the unsaturated carbonyls, I.e. acrolein, sampling andanalysis are addressed in terms of equilibrium chemistry and instability of its DNPH derivative.However, the addition of extraction solvent (toluene) during sampling improved the recovery ofacrolein. This study was further extended to validate water impinger sampling methods (NCASI99.02) for carbonyls, and our lab experiments show that carbonyls, including acrolein, showexcellent recovery.