Use a negative look-behind assertion. 

$str =~ s/(?<!C):/"/g ;

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_______________
DamnDirtyApe 
Those who know that they are profound strive for clarity. Those who
would like to seem profound to the crowd strive for obscurity.
            --Friedrich Nietzsche

In reply to Re: Is there a way I can substitute for ":" except when it is preceded by a letter C by DamnDirtyApe
in thread Is there a way I can substitute for ":" except when it is preceded by a letter C by kirk123

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