A simple direct injection method for GC/MS analysis of PAHs in particulate matter.

A simple direct injection method for analysis of polycyclic aromatic hydrocarbons (PAHs) or other organic components of particulate matter by gas chromatography/mass spectrometry (GC/MS) was developed. This method uses a small custom brass capsule to insert a particulate sample deposited on a quartz fiber filter or powdery sample directly into a GC injector inlet. This approach was applied in the analysis of PAHs in diesel emissions and other particulate samples, which are introduced into the GC and analyzed by MS using selected ion monitoring mode. Quantitation is based on the concentration of PAHs in a standard reference material (SRM), which are certified by US National Institute of Standard Technology to avoid matrix effects on extraction efficiency. A standard filter is prepared by deposition of small amount of SRM of diesel particulate or ambient PM on quartz fiber filter. By this method, the linearity for 12 kinds of PAHs (3 to 6 rings) was demonstrated from 0.022 mg to 0.65 mg of SRM 1650. The linearity of BaP, for example, was confirmed from 0.028 to 0.845 ng. The reproducibility of this method determined by analyzing the standard filter was 15.4%. By selecting an appropriate SRM as a standard material, this method is applicable for analyzing PAHs in fine particulate matter of less than 1 microm from various origins. Preliminary results for a series of ambient particulate matter, roadside PM, diesel soot and sidestream smoke, are presented. This method enables analysis of organic chemical substances, for example PAHs, in PM without any pretreatment using organic solvent, and without any expensive modification of GC instrument.