Acetone and acrolein are both monitored in ambient air,but both compounds present analytical challenges because of their polarity and reactivity.Acetone and acrolein are listed as compounds of interest in EPA Compendium Method TO-15 and Method TO-11A.Method TO-15 requires collection of an ambient air sample in a canister with subsequent analysis by gas chromatography/mass spectrometry(GC/MS).Method TO-11A requires collection of an ambient air sample on a silica gel tube coated with 2,4-dinitrophenylhydrazine(DNPH),with subsequent extraction and analysis by high performance liquid chromatography(HPLC).The analytical challenge posed by acetone arises from the discrepancies between results obtained from two different analytical modes:results obtained by Method TO-15 for acetone are consistently higher(as much as an order of magnitude)than the results obtained by Method TO-11A.To evaluate which method is more accurate,laboratory studies were performed to simultaneously collect test canister and coated sorbent tube cartridges while sampling a test atmosphere containing a known quantity of acetone.Method TO-11A has been disqualified as the methodology of choice for determination of acrolein because of the tautomerization of the acrolein hydrazone derivative on acidified DNPH cartridges.This results in the inability to accurately quantify acrolein at the expected retention time.To evaluate alternative methods,analysis of acrolein in canisters was studied using the analytical methodology of Method TO-15,with GC/MS analysis.In addition,modification of Compendium Method TO-11A with HPLC analysis in cartridges was also evaluated for acrolein recovery by quantifying multiple peaks for acrolein(and its unknown breakdown product)using DNPH cartridges spiked with underivatized standards.
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