CAPILLARY ELECTROCHROMATOGRAPHY - ANALYSIS OF POLYCYCLIC AROMATIC-HYDROCARBONS

Electrochromatography is utilized to separate a mixture of 16 differen t polycyclic aromatic hydrocarbons (PAHs). Fused-silica capillary colu mns ranging in size from 50 to 150 mu m i.d. were packed (20-40-cm sec tions) with 3-mu m octadecylsilica particles. A potential of 15-30 kV is applied across the 30-50-cm total length capillary column to genera te electroosmotic now that carries the PAHs through the stationary pha se. An intracavity-doubled argon ion laser operating at 257 nm is used to detect the PAHs by laser-induced fluorescence. Efficiencies up to 400 000 theoretical plates/m are obtained when detection is performed within the column packing and up to 150 000 theoretical plates/m when detection is performed following a frit (used to hold the packing). Th e reproducibility of the peak retention times is better than 2% (RSD). The limits of detection for individual PAHs range between 10(-17) and 10(-20) mol(10(-9)-10(-11) M), With a linear response spanning 4 orde rs of magnitude in concentration.