No abstract

A second-dimension temperature programming system (2DTPS) for comprehensive two-dimensional gas chromatography (GC × GC) is introduced, and its performance is characterized. In the system, a commercial stainless-steel capillary column was used for the separation, as a heating element, and as a temperature sensor. The second dimension (2D) column was resistively heated and controlled using an Arduino Uno R3 microcontroller. Temperature measurement was accomplished by measuring the overall 2D column’s electrical resistance. A diesel sample was used to compare the 2D peak capacity (2 n c) and resolution (2 R s), while a perfume sample was used to compare the reproducibility of the system for within-day (n = 5) and day-to-day (n = 5) results. The 2 n c improved by 52% with the 2DTPS compared to the secondary oven. The GC × GC system utilizing the 2DTPS had an average within-day and day-to-day relative standard deviation (RSD) of 0.02 and 0.12% for the 1D retention time (1 t R), 0.56 and 0.58% for the 2D retention time (2 t R), and 1.18 and 1.53% for the peak area, respectively.

The second-dimension (2D) temperature programming system (2DTPS) for comprehensive two-dimensional gas chromatography (GC × GC) described in Part 1 was updated and tested with the time-of-flight mass spectrometer (TOFMS) and flow modulator. Addition of a real-time clock and remote port allowed the 2DTPS to be a truly standalone system to be used with any GC × GC instrument. GC × GC reproducibility with the 2DTPS was tested with thermal and flow modulation, coupled with the TOFMS and/or FID to demonstrate compatibility with all typical GC × GC setups. An improvement in the match factor, reverse match factor, and signal-to-noise ratio was found when performing 2D temperature programming. Within-day and day-to-day reproducibility of the 2DTPS for the 1D retention time (≤0.04 and ≤0.05%), 2D retention time (≤0.36 and ≤0.52%), and peak area (≤2.47 and ≤3.37%) were acceptable, while providing flexibility in 2D optimization and improved peak capacity.