Preliminary investigations of preconcentration-capillary electrophoresis-mass spectrometry.

Analyte preconcentration on-line with capillary electrophoresis-mass spectrometry (PC-CE-MS) is described. Preconcentration cartridges were fabricated from PTFE tubing filled with ca. 1-2 mm bed of reversed-phase C18 HPLC packing or polymeric reversed-phase beads. The particle size of the stationary phase was of larger dimension than the internal diameter of the CE capillary. Therefore, PC-CE capillaries were assembled without frit material and held together by friction. The wide applicability of on-line PC-CE-MS is demonstrated by the analysis of solutions containing peptides, proteins, and synthetic analogues of putative metabolites of the neuroleptic agent haloperidol.