Characterization of humic-like substances in airborne particulate matter by capillary electrophoresis

A considerable fraction of the refractory organic carbon in airborne partic ulate matter is to be attributed to humic-like substances (HULIS). Such atm ospheric HULIS isolated from different air dust samples by a microscale ext raction procedure were characterized by capillary electrophoresis (CE). For fractionation of HULIS the working conditions of the CE system were optimi zed using a berate buffer (pH 8.2), polyacrylamide (PAA) coated, fused-sili ca capillary and polyethylene glycol as sieving modifier. Using CE under op timized conditions, HULIS produced electropherograms showing well resolved and reproducible signals.