Basic principles and terms

• Multidimensional gas chromatography (GCxGC) is an automated analytical separation method based on separation of analytes on two different analytical columns with different separation properties.
• Modulator in the GCxGC Chromatography is the device that connects both analytical columns. Using various means it concentrates the analytes that reach it and, in short periodical interval, releases all of the concentrated sample onto the second column (mimicking the injection).
• Modulation time or Modulation period is the duration of the complete cycle of the modulation. The modulation time is equal to the length of the second dimension chromatogram.
• Wrap-around is the occurrence of second-dimension peaks in subsequent elution sequences due to their retention times on the second column being lower than the modulation period.
• Colour plot is a two-dimensional representation of the GCxGC chromatogram where colour represents the intensity of the signal. In Clarity colour plot is equivalent to Isoplot in PDA Extension.
• Apex plot is a two-dimensional representation of the GCxGC chromatogram with graphical marks on places of the GCxGC peak maximums.