Question about C-18 extraction disks
Posted: Tue Jun 02, 2015 8:04 pm
I have just compared the system blank chromatograms for a gradient run where the mobile phase was filtered through a C-18 extraction disk and one where it was not. The blank for the filtered run is noticeably cleaner than the non-filtered blank. Why? I don't understand why mobile phase impurities would be detected as peaks when it seems like they would be masked by the background.