Second dimension temperature programming system for comprehensive two-dimensional gas chromatography with true temperature control

Second-Dimension Temperature Programming System for Comprehensive Two-Dimensional Gas Chromatography. Part 1: Precise Temperature Control Based on Column Electrical Resistance

“…Temperature versus Resistance Calibration. With the previous version of the 2 DTPS, 13 the temperature differential between the 2 D column and the oven was measured directly using a differential thermocouple system, which required calibration by setting the GC oven to discrete temperatures. This was due to the GC oven temperature not being measured by the Arduino microcontroller.…”

“…However, passive cooling by keeping the 2 D column inside the GC oven was sufficient and reduced complexity. 13 Cai and Stearns utilized a collinear heating design, where the 2 D fused silica column and a parallel nickel heating/sensing wire were wrapped together to form a tight bundle. This bundle was mounted on top of the GC, where compressed air controlled by a solenoid valve was used to cool the 2 D column bundle.…”

“…The result is an actual increase in peak capacity per unit time or an increase in peak capacity when comparing equally long separations . Due to the time-limited nature of the 2 D separation, temperature programming is the ideal solution to resolve issues due to wraparound peaks while minimizing resolution loss between weakly retained compounds and maximizing the 2 D peak capacity ( 2 n c ). − The challenge of such an approach, however, is achieving rapid and uniform heating and cooling times, while having accurate temperature measurement with short response times for temperature control.…”

Second-Dimension Temperature Programming System for Comprehensive Two-Dimensional Gas Chromatography. Part 2: Technical Improvements and Compatibility with Flow Modulation and Time-of-Flight Mass Spectrometry

“…5 In our earlier work, a custom-made true second-dimension temperature programming system ( 2 DTPS) was introduced for the first time to combat the general elution problem. 6 In the first part of this paper, a modified system which utilized a commercial stainless-steel column in the 2 D for sample separation, heating, and temperature measurement has been described. 7 Direct resistive heating of the 2 D column made it possible to temperature program and cool the column in the short time frame of the modulation period.…”

“…To demonstrate the compatibility with typical GC × GC setups, , the 2 DTPS was tested with a reversed-flow differential flow modulator and a time-of-flight mass spectrometer (TOFMS). Both the flow modulator , and TOFMS result in substantially different 2 D separation conditions compared to the thermal modulator and FID tested before with the 2 DTPS. , The effect of the 2 D flow fluctuations caused by the rapid 2 D column heating and cooling on the mass spectra was examined. This was critical in demonstrating the system’s compatibility with the extremely powerful GC × GC–MS separation technique.…”