Design of a direct-heating fast temperature programming device for fast gas chromatography

A direct-heating fast temperature programming device for fast gas chromatography was designed and evaluated. A metal capillary column was used both as a separation column and as a heating element. Pulsed current heating strategy was used to heat the column, and at the same time, gave the time lag for self-equilibrium of the metal tubing during a temperature programming. A fast PID control was used to facilitate the fast pulse heating. The correlation coefficients of temperature programming curves were more than 0.9996 between 40-150 with tunable heating rates varying from 1 to 5 degrees C/s. The power consumption of the device was 74 W max, and was less than 50 W on average. The separation time was within 34 s for n-alkanes (nC(8)-nC(17)), with relative standard deviations of the retention times between 0.22% and 0.55%. The cool down time plus the equilibration time is less than 30 s. The device is suitable for the analysi's of semi-and volatile organic compounds in portable GC