Application of sweeping to micellar electrokinetic chromatography-atmospheric pressure chemical ionization-mass spectrometric analysis of environmental pollutants

An application study of sweeping, an on-line sample concentration technique , to micellar electrokinetic chromatography (MEKC) directly combined with m ass spectrometry (MS) using an atmospheric pressure chemical ionization (AP Cl) interface, namely MEKC-APCl-MS, was investigated to enhance the concent ration sensitivity for the analysis of environmental pollutants. Under a ne utral condition, around 100-fold increase in the concentration sensitivity was achieved for several aromatic amines and alkyl phthalates as test sampl es by sweeping-MEKC-APCl-MS compared to conventional MEKC-APCl-MS, whereas under an acidic condition, 100 to 600-fold sensitivity enhancement was gain ed for similar solutes. Linearity of the corrected peak area obtained in th e mass chromatogram against the sample concentration was examined for 3,4-d ichloroaniline and diisopropyl phthalate (DIPP). The estimated limits of de tection for 3,4-dichloroaniline and DIPP were 0.6 and 0.4 ppm, respectively , in terms of the injected sample concentration.