Sub-second thermal desorption of a micro-sorbent trap for the analysis of ambient volatile organic compounds.
This study investigates a novel approach of fast thermal desorption on a micro-sorbent trap for analyzing ambient volatile organic compounds (VOCs) by gas chromatography with flame ionization detection. Unlike conventional approaches, the temperature feedback mechanism for temperature control was abandoned, which often poses a limit to the heating speed due to slow response of the sensor and the control algorithm. Instead, a series of programmed a.c. pulses was given to the Ni-Cr wire coiled around the micro-trap to perform instant heating from room temperature to 250 degrees C within a fraction of a second, maintained at 250 degrees C during injection, and subsequently to 300 degrees C for trap cleaning. Temperature fluctuation around a high temperature set point could be maintained within +/- 10 degrees C. Significant improvement in resolution and peak height was obtained compared to a trap with temperature feedback and control algorithm. While keeping resolution at a satisfactory level, the sub-second desorption approach allows faster chromatography and at the same time increases the sensitivity of VOC analysis.
Chen
Tai-Yi
TY
Institute of Earth Sciences, Academia Sinica, Taipei 11529, Taiwan.
Li
Ming-Jay
MJ
Wang
Jia-Lin
JL
D002849:Chromatography, Gas / Q000379:methods*; D006358:Hot Temperature; D009930:Organic Chemicals / Q000032:analysis*; D015203:Reproducibility of Results; D014835:Volatilization
D009930:Organic Chemicals