Method for analyzing nitrogen trifluoride impurities in high-purity carbon tetrafluoride by gas chromatography

A method for the analysis of trace nitrogen trifluoride impurities in high-purity carbon tetrafluoride (≥ 99.999%) by gas chromatography equipped with a flame ionization detector is described. A 10-port valve and three columns have been used in this instrument system, which can completely separate nitrogen trifluoride and carbon tetrafluoride. In the best analytical conditions, the quantification limit was estimated at 16.62 ppb for an injected sample volume of 1 mL. Furthermore, this method can be completed by one sample injection without the need to vent some of the main component-high-purity carbon tetrafluoride through the valve switch, which is more accurate and simple.