Parameters influencing the precision and accuracy of carbonyl measurements using DNPH cartridges

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:197347

Fung, K ^[1]

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1. AtmAA Inc., Calabasas, CA (United States)

While DNPH cartridges have been used by the author to measure ambient air carbonyl compounds in all major air quality studies throughout California and other parts of the US over the past ten years, there are still remaining issues with the method that need to be addressed in order to produce unbiased results. At typical ambient levels, the method precision is in the range of 10 to 25%. Automated sequential samplers were employed in these studies. They have been very reliable and produced data with good precision when memory-protected timers and flow controllers were used. Samplers account for up to approximately 30% of the error. The precision of the HPLC analytical technique with an autosampler or using an internal standard has a precision of {+-}2% or less. DNPH cartridge blank variability is the largest factor that controls the method`s lower quantifiable limit, which is approximately 0.5 ppbv for 60 liters of air sampled. The cartridge substrate (C18 vs silica) used for DNPH impregnation appeared to have varying extent of ozone interference. While it was thought that DNPH cartridges made with C18 bonded silica have less problems with ozone than plain silica, more recent experimental data showed that when both types were impregnated under identical conditions, silica cartridges performed equally or better, suggesting that the composition of DNPH reagent was also important in determining the extent of the ozone artifact seen.

• OSTI ID: 197347
• Report Number(s): CONF-9405167--
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ACCURACY
AIR POLLUTION MONITORING
AIR SAMPLERS
ALDEHYDES
DATA COVARIANCES
KETONES