The 2.2.2 cryptand [4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo-(8.8.8)-hexacosane] was trapped efficiently on Dowex AG50W-X8 (100-200 mesh) cation exchange resin. The concentration of the 2.2.2 cryptand in water with 0.1-2% methanol, or in 1 N HCl, was decreased by a factor of > 4000 using 1 mL (1.7