An artifact in air carbonyls sampling using C18 DNPH-coated cartridge Original Research Article

A sampling artifact is observed when collecting carbonyl compounds in ambient air using 2,4-dinitrophenylhydrazine (DNPH)-coated C18 cartridges. While lower carbonyls (C1–C4) are not significantly affected, ca. 80% of C5–C8 carbonyl concentrations are due to artifact formation. Furthermore, several high molecular weight carbonyls, containing up to 18 carbons, were artificially produced during sampling probably due to reactions between ambient ozone and C18 sorbent matrix. The use of ozone trap is recommended for carbonyls sampling with DNPH-coated solid sorbents. The most suitable sampling system is a DNPH-coated silica gel cartridge connected to an upstream crystalline KI trap.