Analysis of plasmid after transfection?

[BIOCHEMISTRY]

Dear Net Readers,

    Does anyone know of a protocol (or direct me to a reference) for the
analysis of plasmid DNA after transfection?

    I am interested in a method(s) that can quantitate the plasmid transfected
and determine intactness with respect to supercoiling.  Obviously, a
Southern can be used to check the latter but it is the former that I am
unsure of.

                Thanks in advance,                 Stephen Klautky