Novel Technique for Measuring Low Molecular Weight Chemicals in Indoor Dust

Abstract

A new technique is described which can measure low molecular weight compounds adsorbed onto dust particles in a simple yet accurate way. The technique, gas chromatography-ultraviolet spectrometry (GC-UV), comprises a one-stage thermal desorption oven, a gas flow cell with a miniaturised GC column, and a nitrogen-flushed photo diode array (PDA) detector for fast UV spectra recording. The dust sample is thermally desorbed in the oven and the compounds released are flushed onto the GC column by means of a carrier gas stream. The separated compounds are then registered by the PDA detector and identified by their characteristic gas-phase UV spectra. This method enables the analysis of volatile organic as well as inorganic compounds adsorbed onto dust particles, many of which are difficult to analyse together in one single analysis using conventional methods. For example, both nitric oxide and ammonia can be analysed, as well as hydrogen sulphide, pyridine, 2-furaldehyde, 2-methylfuran, and isoprene. It is concluded that GC-UV may be used as an alternative or to complement other methods for measuring chemicals in indoor dusts, thus improving survey and control of the human exposure to particle-bound irritants and other chemicals.