Alexoff D L, Fowler J S, Gatley S J
Department of Chemistry, Brookhaven National Laboratory, Upton, NY 11973.
Int J Rad Appl Instrum A. 1991;42(12):1189-93. doi: 10.1016/0883-2889(91)90195-7.
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 mequiv.) of AG50W-X8 and a flow rate of approx. 2 mL/min. K+, Cs+, Ag+ and Ba2+ forms were about equal in their ability to remove the 2.2.2 cryptand. A disposable cartridge containing 1 mL of hydrogen form resin was inserted into our automated 18FDG system so that the hydrolysate (in 2 cm3 of 1 N HCl) would pass through the cartridge before final purification. No cryptand was detected in the final product as determined by TLC with idoplantinate visualization. The detection limit was 2.5 micrograms/mL. Less than 3% of the total starting radioactivity was retained by the cation column. Quality assurance tests including apyrogenicity, sterility, radiochemical purity, carbohydrate composition and pH were not compromised by the incorporation of the cryptand removal cartridge.
2.2.2穴醚[4,7,13,16,21,24-六氧杂-1,10-二氮杂双环-(8.8.8)-二十六烷]能有效地截留在Dowex AG50W-X8（100-200目）阳离子交换树脂上。在含有0.1-2%甲醇的水中或1N盐酸中，使用1mL（1.7毫当量）AG50W-X8且流速约为2mL/分钟时，2.2.2穴醚的浓度降低了4000倍以上。K⁺、Cs⁺、Ag⁺和Ba²⁺形式在去除2.2.2穴醚的能力上大致相当。将一个装有1mL氢型树脂的一次性柱芯插入我们的自动化18FDG系统中，以便水解产物（在2cm³ 1N盐酸中）在最终纯化之前通过该柱芯。通过用碘铂酸盐显色的薄层色谱法测定，最终产物中未检测到穴醚。检测限为2.5微克/毫升。阳离子柱保留的放射性活度不到总起始放射性活度的3%。包括无热原性、无菌性、放射化学纯度、碳水化合物组成和pH值在内的质量保证测试不受穴醚去除柱芯引入的影响。
