[en] Concentration of kryptofix 2.2.2 in [1^8F]FDG solutions and standard solutions of kryptofix 2.2.2 was determined by two methods: Visualization of combination of K2.2.2 with iodine vapor and iodo platinate reagent. In both methods, concentration difference of K2.2.2 solutions was appeared as difference in color intensity of revealed spots on TLC. The detection limit of K2.2.2 by iodine vapor and iodo platinate reagent is 25 and 2 ppm, respectively. Both methods can be used to release or reject the quality of [1^8F]FDG radiopharmaceutical for intravenous injection, but the second method is more suitable because of taking shorter time