On the applicability of XPS for quantitative total organic and elemental carbon analysis of airborne particulate matter

X-ray photoelectron spectroscopy (XPS) is a widely used surface analysis technique that in recent years has been used by a number of groups to analyse particulate matter collected onto filters. In this communication, XPS is compared to the standard method for determining the ratio of the elemental carbon to total carbon in all forms in the particulates using a PM10 quartz filter sample. The results obtained from the two methods are significantly different, suggesting that XPS gives a better indication of the chemistry of the surface of the particle, whereas the standard method is more relevant to the composition of the particles as a whole. Therefore, each technique has valid applications—XPS may be better for use in those toxicology studies where surface chemistry is important, whereas the standard method may be best for tracing the origin of particles through knowledge of the average particle composition.