Determination of low-molecular-mass carboxylic acids in atmospheric aerosol and vehicle emission samples by capillary electrophoresis

A method is developed for the determination of a large number of airborne a nd vehicle-emitted low-molecular-mass mono- and dicarboxylic acids using ca pillary electrophoresis with indirect UV detection. A background electrolyt e (BGE) consisting of 2,6-naphthalenedicarboxylic acid and tetradecylmethyl ammonium bromide, adjusted to pH 6.2 with 2,2-bis(hydroxymethyl)-2,2',2 " - nitrilotriethanol, is employed. Separations are robust using the buffered B GE, proper rinse steps, and constant current mode with migration time varia tions less than 3% RSD on a day-to-day basis, using different capillaries a nd performed by different analysts, Detection limits are at the tens of mug /l level using pressure injection. A comparison of the CE method with ion c hromatography is also made. (C) 2001 Published by Elsevier Science B.V.