TY - JOUR
T1 - Effect of Surface Adsorption on Temporal and Spatial Broadening in Micro Free Flow Electrophoresis
AU - Geiger, Matthew
AU - Harstad, Rachel K.
AU - Bowser, Michael T.
N1 - Publisher Copyright:
© 2015 American Chemical Society.
PY - 2015/10/23
Y1 - 2015/10/23
N2 - Analyte adsorption onto surfaces presents a challenge for many separations, often becoming a significant source of peak broadening and asymmetry. We have shown that surface adsorption has no effect on peak position or spatial broadening in micro free flow electrophoresis (μFFE) separations. Surface adsorption does affect the time it takes an analyte to travel through the μFFE separation channel and therefore contributes to temporal broadening. These results were confirmed using μFFE separations of fluorescein, rhodamine 110, and rhodamine 123 in a low ionic strength buffer to promote surface adsorption. Peak widths and asymmetries were measured in both the temporal and spatial dimensions. Under these conditions rhodamine 123 exhibited significant interactions with the separation channel surface, causing increased peak broadening and asymmetry in the temporal dimension. Broadening or asymmetry in the spatial dimension was not significantly different than that of fluorescein, which did not interact with the capillary surface. The effect of strong surface interactions was assessed using μFFE separations of Chromeo P503 labeled myoglobin and cytochrome c. Myoglobin and cytochrome c were well resolved and gave rise to symmetrical peaks in the spatial dimension even under conditions where permanent adsorption onto the separation channel surface occurred.
AB - Analyte adsorption onto surfaces presents a challenge for many separations, often becoming a significant source of peak broadening and asymmetry. We have shown that surface adsorption has no effect on peak position or spatial broadening in micro free flow electrophoresis (μFFE) separations. Surface adsorption does affect the time it takes an analyte to travel through the μFFE separation channel and therefore contributes to temporal broadening. These results were confirmed using μFFE separations of fluorescein, rhodamine 110, and rhodamine 123 in a low ionic strength buffer to promote surface adsorption. Peak widths and asymmetries were measured in both the temporal and spatial dimensions. Under these conditions rhodamine 123 exhibited significant interactions with the separation channel surface, causing increased peak broadening and asymmetry in the temporal dimension. Broadening or asymmetry in the spatial dimension was not significantly different than that of fluorescein, which did not interact with the capillary surface. The effect of strong surface interactions was assessed using μFFE separations of Chromeo P503 labeled myoglobin and cytochrome c. Myoglobin and cytochrome c were well resolved and gave rise to symmetrical peaks in the spatial dimension even under conditions where permanent adsorption onto the separation channel surface occurred.
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U2 - 10.1021/acs.analchem.5b02262
DO - 10.1021/acs.analchem.5b02262
M3 - Article
C2 - 26496470
AN - SCOPUS:84948466409
SN - 0003-2700
VL - 87
SP - 11682
EP - 11690
JO - Analytical Chemistry
JF - Analytical Chemistry
IS - 23
ER -