PRECONCENTRATION OF ALIPHATIC-AMINES FROM WATER DETERMINED BY CAPILLARY ELECTROPHORESIS WITH INDIRECT UV DETECTION

Preconcentration methodology based on adsorption chromatographies for enriching aliphatic amines (C1 to C4 substituted primary, secondary, a nd tertiary) and alkanolamines in water was studied by free zone capil lary electrophoresis (CZE) with indirect UV detection. The solid-phase extraction of amines from water (pH 5) as a preconcentration step was studied for ion exchange solid-phase extraction (SCX) cartridges, cat ion ion exchange extraction disks, and ion-pairing with C-18 extractio n disks. In the course of the investigations, the electrophoretic prop erties of the amines was studied in some detail in order to optimize s eparations and detection limits. The indirect mode is particularly pow erful in being able to detect primary through quarternary amines witho ut derivatization. Mobilities of amines were correlated with their Sto kes' radii. Increased selectivity for resolving closely related amines under CZE was explored using nonionic surfactants, pH adjustment, and optimized background electrolyte. Techniques were developed for obtai ning stable baselines in the indirect detection mode. Linearity, sensi tivity, and efficiency were explored for this mode of detection for a large set of amines.