Towards adaptive method for peak migration time correction: discretization period in electropherograms

Abstract

Capillary electrophoresis often causes unrepeatable peak migration times in the electropherogram due to changes of electroosmosis, yet in some cases this separation technique does not have a replacement alternative. Some attempts to overcome this issue have been performed introducing internal standards into the sample and compensating peak shifting in time. However, existing vector calculation-based methods are computationally intensive for portable instrumentation and usually limited to post-processing applications with 1 or 2 markers. In this work, an original approach of compensating peak migration time shift via signal discretization period correction is proposed. Using the proposed method, the number of reference points or markers that are used for compensation is extended. This method is effective in compensating migration time of peaks in real samples, where high sample injection volumes are used. Using 4 reference peaks in compensation, the method was capable of reducing the relative standard deviation of migration time of the peaks in the electropherograms more than 15 times. Corrected signal discretization periods indicated very high correlations with recorded separation currents, what can be perspective developing an adaptive peak migration time compensation method in capillary electrophoresis.

Providing Enhanced Migration Time Reproducibility with a High-Voltage-Compatible Flow Sensor for Capillary Electrophoresis

“…To account for these changes in the migration time, it is possible to use computerized time scale compensation in CE, which mainly focuses on peak mobility recalculation based on an EOF marker, internal standard reference, thermal time marks, or a two-step method. − Unfortunately, recalculation approaches fail in cases where EOF fluctuations are unpredictable and nonlinear . While thermal marks are capable of handling cases where the change of EOF velocity fluctuates, they introduce baseline distortion spikes that can interfere with the peaks of the analytes …”