TY - JOUR
T1 - Dynamic on-column pH monitoring in capillary electrophoresis
T2 - Application to volume-limited outlet vials
AU - Timperman, Aaron
AU - Tracht, Scott E.
AU - Sweedler, Jonathan V.
N1 - Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 1996/8/1
Y1 - 1996/8/1
N2 - With capillary electrophoresis, buffer pH must be constant to achieve consistent migration times. Irreproducible separations have been attributed to pH changes due to water hydrolysis in the inlet/outlet vials. A method of measuring the pH of the electrolyte on-column is described that uses wavelength-resolved fluorescence detection. C.SNARF-1 is a fluorescent pH indicator that has a large change in fluorescence emission profile depending on pH. When it is incorporated into the running buffer, monitoring the pH-dependent emission spectra of the C.SNARF-1 allows column pH to be calculated. With reduced-volume outlet buffer vials in the nanoliter to low microliter range, significant changes in pH and column conductivity are measured during a single electrophoretic run, with pH fronts greater than 3 units passing a fixed point on the capillary over a several second period. These changes appear to be caused by reverse-migrating OH produced at the capillary outlet by the hydrolysis of water.
AB - With capillary electrophoresis, buffer pH must be constant to achieve consistent migration times. Irreproducible separations have been attributed to pH changes due to water hydrolysis in the inlet/outlet vials. A method of measuring the pH of the electrolyte on-column is described that uses wavelength-resolved fluorescence detection. C.SNARF-1 is a fluorescent pH indicator that has a large change in fluorescence emission profile depending on pH. When it is incorporated into the running buffer, monitoring the pH-dependent emission spectra of the C.SNARF-1 allows column pH to be calculated. With reduced-volume outlet buffer vials in the nanoliter to low microliter range, significant changes in pH and column conductivity are measured during a single electrophoretic run, with pH fronts greater than 3 units passing a fixed point on the capillary over a several second period. These changes appear to be caused by reverse-migrating OH produced at the capillary outlet by the hydrolysis of water.
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U2 - 10.1021/ac960166b
DO - 10.1021/ac960166b
M3 - Article
C2 - 8694265
AN - SCOPUS:0030211174
SN - 0003-2700
VL - 68
SP - 2693
EP - 2698
JO - Analytical Chemistry
JF - Analytical Chemistry
IS - 15
ER -