A simplified apparatus for ambient formaldehyde detection via GC-pHID
2003; Elsevier BV; Volume: 37; Issue: 18 Linguagem: Inglês
10.1016/s1352-2310(03)00178-x
ISSN1873-2844
AutoresJames R. Hopkins, T. J. Still, S. Al-Haider, Iain Fisher, Alastair C. Lewis, Paul W. Seakins,
Tópico(s)Spectroscopy and Laser Applications
ResumoAn apparatus has been developed for the direct determination of ambient, atmospheric formaldehyde using gas chromatography. A loop sample of 1–6 ml is transferred onto the column and the formaldehyde is focused with a cold trap. Following separation, formaldehyde is detected with an argon doped, pulsed discharge helium ionization detector. Absolute values are obtained via calibration with a permeation source. A detection limit of 42 pptv is calculated. The relatively high duty cycle (∼11 h−1) allows measurements to be taken on timescales that are short compared to the atmospheric lifetime of formaldehyde. The reliability of the apparatus has been investigated via a 4-week field campaign at an urban site in Leeds, UK. Diurnal profiles are observed with evidence for both primary emissions from traffic and secondary, photochemical production. A decrease in formaldehyde concentrations was observed during rain events.
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