Optimizing a dansylhydrazine (DNSH) based method for measuring airborne acrolein and other unsaturated carbonyls

The Passive Aldehydes and Ketones Sampler (PAKS) method has been developed to measure airborne carbonyls ( aldehydes and ketones) by derivatizing the carbonyls with dansylhydrazine (DNSH) on a solid sorbent.(1) The method collection efficiencies are similar to 100% for most saturated carbonyls, but are significantly lower for unsaturated carbonyls. In this study, we examined the mechanisms of DNSH reactions with unsaturated carbonyls, focusing on acrolein. With a better understanding of these mechanisms, we modified the sampling substrate conditions and HPLC analysis conditions of the original PAKS method, resulting in substantially improved collection efficiencies for acrolein and crotonaldehyde. Evaluated under a variety of conditions ( temperature, humidity, presence of ozone), the modified PAKS method had a collection efficiency of 99% +/- 5% for acrolein (N = 36) and 96% +/- 20% for crotonaldehyde (N = 6). The acrolein DNSH derivative was stable within 9.6% of the initial amount, after 14 days of storage at 4 degrees C, on the collection medium; and stable within 2.8% of the initial amount, after 16 days of storage at room temperature, in extract.