Analysis of indoor gaseous formic and acetic acid, using radial diffusive samplers

13 November 2019

Stranger, M., Potgieter-Vermaak, S., Sacco, P., Quaglio, F., Pagani, D. Cocheo, C., Locateli Godoi, A.F., Van Grieken, R.

Environmental Monitoring and Assessment, 2009, 149(1-4), 411-7.

A diffusive sampling method for the determination of gaseous acetic and formic acids, using a radial symmetry diffusive sampler, has been optimised for a 7-day exposure time in this study. Sampling rate determinations were performed on data obtained from a dynamic exposure chamber, simulating the indoor conditions of an empty, closed, room, at room temperature and minimal wind speed. Analysis has been performed by means of ion chromatography. The sampling rates for formic acid concentrations of 128 μg·m⁻³ and 1248 μg·m⁻³ were determined to be 91.2 ± 3.9 ml·min⁻¹ and 111.6 ± 2.8 ml·min⁻¹, respectively. The acetic acid sampling rate was independent of the concentration in the range 160 μg·m⁻³–1564 μg·m⁻³, and amounted to 97.3 ± 3.1 ml·min⁻¹. Experimentally determined sampling rates showed deviations of 3% for acetic acid, and 3–21% for formic acid, in relation to theoretically derived values. The blank values were as low as 1.69 ± 0.07 μg for formic acid and 1.21 ± 0.14 μg for acetic acid, and detection limits lower than 0.5 μg·m⁻³ could be achieved, which is an improvement of 98–99% compared to previously validated diffusive sampling methods. This study describes the first step of an extended validation program in which the applicability of these types of samplers for the measurement of organic acids will be validated and optimised for the environmental conditions typical for museum showcases.