Compensation of Two Kinds of Bias in Capillary Zone Electrophoresis and Its Use in Internal Normalization Quantitation

Electrokinetic injection is less commonly used for quantitative HPCE analysis than hydrodynamic injection because of injection bias. At the same time, the internal normalization method is less commonly used than other quantitation methods due to the tediousness of its peak area correction. In this paper, it is shown that, under appropriate conditions, the biases due to electrokinetic injection and migration speed can be totally canceled. If the sample solution is prepared in run buffer solution, keeping the pH and ionic strength the same in both solutions, the dual biases can be mutually compensated. In this case, only the response factor is required to correct the integrated peak areas, which makes the peak area correction in HPCE as simple as in chromatography. With the method proposed here, quantitation with internal normalization, which is well known for its low susceptibility to the variation of experimental parameters, can be as conveniently used in HPCE as in chromatography.