Separation of metalloporphyrins by capillary electrophoresis with UV detection and inductively coupled plasma mass spectrometric detection

Vitamin B12, cobalt protoporphyrin, manganese protoporphyrin, and zinc protoporphyrin were separated using capillary electrophoresis, and a comparison was made between detection with inductively coupled plasma mass spectrometry (ICP-MS) and UV detection. Absolute limits of detection were slightly better with ICP-MS detection than with UV detection, but for both methods absolute detection limits were in the picogram range. The migration times of the analytes decreased by several minutes when ICP MS detection was employed, and this phenomenon was believed to be a result of a “suction effect” that developed when the CE capillary was interfaced to the ICP-MS nebulizer. However, the resolution between species containing the same metal atom was not altered significantly, and the separation was completed in much less time relative to separations performed with UV detection.