Add-On Device Powered by Parallelized Adsorption Traps for Preconcentrator-GC-MS Measurement of sub-pmol/mol Levels of NF.

In this study, an add-on preconcentration device powered by parallelized pretraps (PPTs) was utilized to measure the sub-pmol/mol levels of NF in N. The add-on preconcentrator was coupled to the detachable trap preconcentrator (DTP) with a gas chromatograph-mass spectrometer [ 3342-3349]. The breakthrough volume of the parallel configuration was found to be substantially higher than that of the serial configuration with the same amount of adsorbent (HayeSep D). Liquid oxygen (LO) cooling (-183 °C) exhibited better preconcentration performance for NF in N compared to NF in air (N + O) with liquid nitrogen cooling (-195 °C) and NF in air with LO cooling. The DTP unit was essential to discriminate residual species, such as N, O, CO, and CF, of which the preconcentrated portion in the PPT can be excessive, enabling the overwhelm filtering capability of the quadrupole mass spectrometer. The limit of detection of NF in N of the PPT/DTP/gas chromatograph-mass spectrometer was 0.01 ppt, which is significantly better than that determined without using the add-on preconcentration device (0.21 ppt).