Journal of Separation Science

Cover image for Vol. 38 Issue 22

Impact Factor: 2.737

ISI Journal Citation Reports © Ranking: 2014: 21/74 (Chemistry Analytical)

Online ISSN: 1615-9314

Associated Title(s): ELECTROPHORESIS

July 31, 2007

Simultaneous determination of formic acid and lower carbonyls in air samples by DNPH derivatization

The reactions of anthropogenic and biogenic hydrocarbons with hydroxyl radicals and ozone in the troposphere yield oxygenated species including carbonyls and carboxylic acids. Formaldehyde and formic acid are the most abundant gaseous components of the two classes of organic compounds. They play important roles in the oxidizing capacity of the atmosphere and in the precipitation acidity, respectively. To evaluate models that predict the role of oxygenated volatile organic compounds in tropospheric chemistry, it should be convenient to develop methods capable of determining different species in the same air sample. The determination of carbonyls in air is commonly based on their reaction with 2,4-dinitrophenylhydrazine (DNPH) absorbed on silica gel cartridges. Formed hydrazones are analyzed and quantified by HPLC with UV photometric detection after their extraction from DNPH-coated particles with acetonitrile.
The classical derivatization method of carbonyls based on DNPH-coated silica cartridges was tested by Massimiliano Possanzini, Giorgio Tagliacozzo, and Angelo Cecinato to concurrently measure lower carbonyls and carboxylic acids in air samples. The performance of these cartridges with respect to formic and acetic acids was evaluated in a number of laboratory measurements on collection and reaction efficiencies. The results showed that HCOOH appeared to have been efficiently collected and derivatized up to air flow rates of 350 mL min-1, whilst CH3COOH was almost completely lost from the cartridge above 100 mL min-1. Also due to the high limit of detection of HCOOH, the DNPH method might be used only in indoor environments polluted by formic acid as well as carbonyls.

Massimiliano Possanzini, Giorgio Tagliacozzo, and Angelo Cecinato, J. Sep. Sci. 2007, 30 (15).
Full article online, DOI: 10.1002/jssc.20060109