Unsaturated Dicarbonyl Products from the OH-Initiated Photo-Oxidation of Furan, 2-Methylfuran and 3-Methylfuran

This study presents the application of O-(2,3,4,5,6)-pentafluorobenzyl-hydroxylamine hydrochloride (PFBHA) on-fibre derivatisation Solid Phase Microextraction (SPME) to the sampling and quantification of the dicarbonylic products obtained in the photo-oxidation of furan, 2-methylfuran and 3-methylfuran in the presence of HONO: butenedial, 4-oxo-2-pentenal and 2-methylbutenedial, respectively. The combination of the methodology of SPME in the furan systems holds great potential in the elucidation of aspects of the chemistry of 1,4-dicarbonyls unknown to date. This methodology can accomplish discriminated quantification of the cis and trans isomers. The use of PTR-MS applied to the same purpose is also presented and the advantages of the combined use of the two methodologies discussed. The experiments were carried out in the outdoors simulation chambers EUPHORE. The results confirm that 1,4-dicarbonyls are the main products of the OH-initiated oxidation of furan and its methylated derivatives, a fact with environmental implications. Molar yields of (1.09±0.41) and (0.90±0.36) were obtained in two experiments of furan photo-oxidation. The yields of 4-oxo-2-pentenal and methylbutenedial were estimated to be (0.60±0.24) and (0.83±0.33) respectively, assuming the same SPME response factor as for butenedial. Yields of other products, i.e., formaldehyde, glyoxal, maleic anhydride and formic acid in the furan experiments and also methylglyoxal (in the case of the methyl derivatives) are also provided. Most of these were secondary products formed from the subsequent degradation of the 1,4-dicarbonyls. Furthermore, the 1,4-dicarbonyls have also been identified in the chemical characterization of the aerosols formed in the reactions. The yield of aerosols quantified were (8.5±0.8) % in the photo-oxidation of furan, (1.85±0.18) % in the photo-oxidation of 2-methylfuran and (5.5±0.5) % in the photo-oxidation of 3-methylfuran), at the following concentrations of their precursors: 829±249 ppbV and 748±224 (in two furan experiments), 633±190 in the 2-methylfuran and 641±192 ppbV in the 3-methylfuran experiment.

GOMEZ ALVAREZ Elena;  BORRÁS Esther;  VIIDANOJA Jyrki;  HJORTH Jens; 

2009-11-26

PERGAMON-ELSEVIER SCIENCE LTD

JRC49880

1352-2310,   

www.elsevier.com/locate/atmosenv,    https://publications.jrc.ec.europa.eu/repository/handle/JRC49880,   

10.1016/j.atmosenv.2008.12.019,