Determination of airborne formaldehyde and ten other carbonyl pollutants using programmed temperature vaporization-large volume injection-gas chromatography

Abstract

Long-term indoor-air limit for formaldehyde stipulated by the European Commission is 1 μg/m3, while the World Health Organization has set a threshold of 100 μg/m3 that should not be exceeded for more than 30 min. To date, however, only a few analytical techniques have been developed that can be used to detect formaldehyde at these very restrictive limits. Thus, there is a need to develop for comprehensive methods for analyzing airborne formaldehyde and other carbonyl pollutants in the ambient environment. The aim of this study is to develop a highly sensitive online automated preconcentration gas chromatographic method using large-volume injection with a programmed temperature vaporization injector for the analysis of airborne formaldehyde and ten other carbonyl compounds. The influence of several parameters, such as the maximum volume injected, programmed temperature vaporization transfer time and temperature, carrier gas flow rate, and type of packing material was investigated. After optimization, highly satisfactory results in terms of the absolute and methodological detection limits were achieved, i. e. as low as the μg/m3 level for all the carbonyl pollutants studied. A commercially available sampler, originally designed for active sampling, was evaluated as a passive sampling device; this optimized technique was applied to monitor the concentrations of carbonyl pollutants in the indoor air of ten public buildings in Florence. The strength of this methodology lies both in the low detection limits reached in the simultaneous analysis of a wide group of 2,4-dinitrophenylhydrazine derivatives, and the potential adaptability of this method to other gas chromatographic applications to achieve lower sensitivity.