Improving the reproducibility in capillary electrophoresis by incorporating current drift in mobility and peak area calculations

TY - JOUR

T1 - Improving the reproducibility in capillary electrophoresis by incorporating current drift in mobility and peak area calculations

AU - Petersen, Nickolaj J.

AU - Hansen, Steen H

N1 - © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

PY - 2012/3

Y1 - 2012/3

N2 - The traditional way of calculating mobility and peak areas in capillary electrophoresis does not take into account the changes in the buffer viscosity at different thermostatic control and that the analytes may accelerate during the individual runs due to Joule heating effects. We present a method for accounting for these changes based on the monitored changes in current during the separation. The calculation method requires measuring the initial resistance of the buffer filled capillary, performed using a 0.2 min voltage ramping at the start of a separation. The mobility calculation corrected for current drift allowed identification of the tested analytes independent from capillary dimensions, electric field strengths and temperature control. Furthermore, the peak areas become less influenced by the experimental conditions, since the velocities of the analytes passing the detector are corrected for the acceleration during the run. The short voltage ramping could be further used to evaluate the heat transfer of the capillary to the surroundings and to estimate the temperature changes during the separation. The temperature was shown to change the ionization of 2-phenylethylamine in accordance to a pKa dependency of primary amines reported in literature.

AB - The traditional way of calculating mobility and peak areas in capillary electrophoresis does not take into account the changes in the buffer viscosity at different thermostatic control and that the analytes may accelerate during the individual runs due to Joule heating effects. We present a method for accounting for these changes based on the monitored changes in current during the separation. The calculation method requires measuring the initial resistance of the buffer filled capillary, performed using a 0.2 min voltage ramping at the start of a separation. The mobility calculation corrected for current drift allowed identification of the tested analytes independent from capillary dimensions, electric field strengths and temperature control. Furthermore, the peak areas become less influenced by the experimental conditions, since the velocities of the analytes passing the detector are corrected for the acceleration during the run. The short voltage ramping could be further used to evaluate the heat transfer of the capillary to the surroundings and to estimate the temperature changes during the separation. The temperature was shown to change the ionization of 2-phenylethylamine in accordance to a pKa dependency of primary amines reported in literature.

KW - Electromagnetic Fields

KW - Electrophoresis, Capillary

KW - Models, Chemical

KW - Phenethylamines

KW - Reproducibility of Results

KW - Temperature

KW - Viscosity

U2 - 10.1002/elps.201100551

DO - 10.1002/elps.201100551

M3 - Journal article

C2 - 22528422

SN - 0173-0835

VL - 33

SP - 1021

EP - 1031

JO - Electrophoresis

JF - Electrophoresis

IS - 6

ER -