Carbon Isotopic Analysis of Atmospheric Carbonyls Via Cysteamine Derivatization
2021
Guo, Song Jun
Isotopic effects of carbonyls were investigated using the simulation reactions of carbonyls with the cysteamine derivatization. Furthermore, variations of carbon isotopic for three dominant carbonyls including formaldehyde, acetaldehyde, and acetone in the roadside air of Nanning were measured using a developed method. It was found that there was a small difference in δ¹³C values (0.04 to 0.50‰) between the calculated and measured carbonyl derivatives, indicating that no effects on the carbon isotopic fractionation occurred in the simulation reactions of carbonyls with cysteamine. The subsequent ambient air measurements showed that [Formula: see text]C values of formaldehyde, acetaldehyde, and acetone were − 36.02 to − 31.18‰, − 35.35 to − 32.01‰, and − 30.45 to − 29.09‰, respectively. Formaldehyde, acetaldehyde and acetone in the air were all enriched in the early afternoon by round 0.5–6‰ in ¹³C compared to other sampling durations, which caused likely due to the contribution from positive photo-oxidation production of hydrocarbons. Finally, it was revealed that all the measured [Formula: see text]C values (− 36.02 to − 29.09‰) were in the range of the forecasted [Formula: see text]C values (− 43.00 to − 26.00‰) in terms of ¹³C mass balance of carbonyls and their hydrocarbon precursors, indirectly confirming such positive productions in the air.
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