Measurement of Formaldehyde and Acetaldehyde Using 2,4-Dinitrophenylhydrazine-impregnated Cartridges During the Carbonaceous Species Methods Comparison Study
Titel:
Measurement of Formaldehyde and Acetaldehyde Using 2,4-Dinitrophenylhydrazine-impregnated Cartridges During the Carbonaceous Species Methods Comparison Study
Auteur:
Fung, Kochy Wright, Barbara
Verschenen in:
Aerosol science and technology
Paginering:
Jaargang 12 (1990) nr. 1 pagina's 44-48
Jaar:
1990
Inhoud:
During the Carbonaceous Species Method Comparison Study (CSMCS) conducted in August, 1986 by the California Air Resources Board (CARB) in Glendora, CA, carbonyls in ambient air were collected using cartridges impregnated with 2,4-dinitrophenylhydrazine (DNPH) and phosphoric acid. The resulting hydrazones, including those of formaldehyde and acetaldehyde, were separated and quantitated using high-performance liquid chromatography (HPLC). During the 10-day study, 110 samples were collected, including 12 field blanks, 12 backup cartridges, and 8 duplicate (collocated) samples. The measured concentrations ranged from 3.5 to 21.3 ppb for formaldehyde, and from 2.4 to 17.4 ppb for acetaldehyde. Diurnal variations, typically high around midday and low at nighttime, persisted throughout the study period. The coefficients of variation calculated from duplicate samples were 5.4% for formaldehyde and 4.0% for acetaldehyde. On the average, the DNPH method gave formaldehyde levels ∼ 0.7 ppb lower than the mean of spectroscopic techniques. By comparison, the tunable diode laser absorption spectroscopy (TDLAS) results were 0.5 ppb lower, while the Fourier transform infrared spectroscopy (FTIR) and the differential optical absorption spectroscopy (DOAS) results were 0.2 and 0.3 ppb higher, respectively. These observed differences for the four methods were all statistically significant by the correlated t-test.
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