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PMID: 15228121

Osafune T et al
Anal Sci 2004 Jun;20(6):971-4
Influence of the pH on separating DNA by high-speed microchip electrophoresis.

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A simpler explanation for the findings: Temperature effects

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BioMed Crit Comm 2009; 2:1570
Posted: May 15, 2009 CCID: 1570
Commentator: Kern SE	Ave. score of this commentator: 2.5 for 17 scored comments.

As noted by us (PMID: 15351274) and by others, temperature is one determinant of the speed of DNA migration in electrophoresis. These authors noted that their phosphate buffer had a nearly 20% higher conductance than the TBE buffer. The phosphate buffer would thus generate more Joule heating at a given voltage than would the TBE solution, permitting the DNA to migrate faster. The endosmotic flow measured by the authors could also affect DNA net migration rates, but the data on this flow were not presented. If the authors were interested in the intrinsic differences between TBE and sodium phosphate buffer, all experiments should have started with solutions of identical conductivity. The conclusion, that "DNA separation was particularly affected by both the buffer composition and the pH", is meaningless without having controlled for the differences in conductivity and temperature. SE Kern sk@jhmi.edu

Key authors in this publication:

Baba Y, Nagata H, Osafune T.

View Linked Comments	PMID: 15228121
Osafune T et al Anal Sci 2004 Jun;20(6):971-4 Influence of the pH on separating DNA by high-speed microchip electrophoresis.