Splitter-based Non-cryogenic Artificial Trapping (SNAT): Novel modulation mechanism in comprehensive two dimensional gas chromatography

Abstract

• Artificial modulation concept and the system configuration were developed. • This applied a Deans Switch and a splitter system. • This could split and artificially focus highly volatile compounds without cryogen consumption. • The approach could be applicable with a long 2 D column and wide modulation period. • Solvent mixture, lighter gas, gasoline and lubricant separations were demonstrated. Splitter-based non-cryogenic artificial trapping (SNAT) modulation approach in comprehensive two dimensional gas chromatography (GC × GC) was developed. The system employed semi-nonpolar/polar columns, a restrictor and a microfluidic Deans switch (DS) applying periodic multiple heartcuts (H/C) and several splitters with different dimensions located between the first ( 1 D) column outlet and the DS. These splitters enabled artificial split-and-trap process consisting of 1) systematic pulse splitting, 2) split-pulse delay and 3) the pulse combination prior to 4) periodic selective H/C of the overlapped pulse. The interval between each H/C was herein defined as a new parameter called artificial modulation period ( P AM ). Methods to adjust sampling time ( t samp ) and P AM were described with t samp / P AM ratios equal to numbers of the splitters ( n split ). This was demonstrated for artificial modulation of a solvent mixture with n split = 4 and 8 as well as separation of lighter gas, lubricant and diesel samples using the P AM range of 0.23–4.57 min. Intraday and interday percentages of relative standard deviation (%RSD) of peak areas in repeated separations of the solvent mixture ( n = 15) were within the range of 0.7–12% and 4–10%, respectively. The%RSD ranges for the 1D modulated times were 0–0.2% and 0–0.09%, respectively. The established approach enables artificial split-and-trap of highly volatile compounds without cryogen consumption and use of a long second dimensional ( 2 D) column.