Electrophoresis: Representative Method and Evaluation

Representative Method

Although each capillary electrophoretic method has its own unique considerations, the following description of the determination of a vitamin B complex provides an instructive example of a typical procedure.

Evaluation

When compared with GC and HPLC, capillary electrophoresis provides similar lev- els of accuracy, precision, and sensitivity and a comparable degree of selectivity. The amount of material injected into a capillary electrophoretic column is significantly smaller than that for GC and HPLC; typically 1 nL versus 0.1 μL for capillary GC and 1–100 μL for HPLC. Detection limits for capillary electrophoresis, however, are 100–1000 times poorer than those for GC and HPLC. The most significant advan- tages of capillary electrophoresis are improvements in separation efficiency, time, and cost. Capillary electrophoretic columns contain substantially more theoretical plates (~106 plates/m) than that found in HPLC (~105 plates/m) and capillary GC columns (~103 plates/m), providing unparalleled resolution and peak capacity. Sep- arations in capillary electrophoresis are fast and efficient. Furthermore, the capillary column’s small volume means that a capillary electrophoresis separation requires only a few microliters of buffer solution, compared with 20–30 mL of mobile phase for a typical HPLC separation.