Agarose gel electrophoresis (AGE) analysis is an important method for monitoring of plasmid DNA (pDNA) quality, with ability to separate pDNA isoforms (sc, oc, lin, multimer). Plasmid linearization can be monitored for purposes of producing starting material for mRNA production. Electrophoretic conditions and, more importantly, matrix used for sample dilution before gel loading can affect analytical results. We have observed that purified linear pDNA shows an additional band in AGE analysis of the sample in water medium, which can lead to misinterpretation of results.
