Abstract: Objective To explore a direct method to analysis of Kryptofix 2.2.2 that is used as a phasetransfer reagent to facilitate the nucleophilic reaction of 18F-FDG. Methods To apply the Gas Chromatography coupled with a flame ionization detector(FID) and a nitrogen-selective detector(NPD) and use the OV-101 megabore capillary column. Results Kryptofix 2.2.2 can be eluted intact in 2.4min time from the column, and detected at the levels as low as 0.50?g/mL;The average residual of 30 normal batchs in our facility are 1.10±0.15?g/ml(n=30);The levels of the cryptand in 10 batchs preparation of FDG without the AG50 Resin are 106.0±21.0?g/ml(n=10). Conclusions direct measurement of Kryptofix 2.2.2 levels in routine 18F-FDG preparation is possible using Gas Chromatography coupled with NPD detector, and a high sensitivity (50 times better than TLC method) can be get; It can use to analysis Kryptofix 2.2.2 as the 18F-FDG Daily Quality Control measurement quickly and quantitatively. Key words 18F-FDG, Kryptofix 2.2.2, Gas Chromatography, Quality Control