Spectrophotometric Determination of Kryptofix 2.2.2 Using TCNQ

Abstract

The interactions of the electron donors kryptofix (K-222) with 7,7,8,8-Tetracyanoquino- dimethane (TCNQ) were studied spectrophotometrically in aceton/water at several temperatures. The UV-vis spectra of the formed molecular charge transfer (CT) complexes were recorded. The molecular structures of the CT-complexes were independent of the position of the amino group on the K-222 and were formulated as [(K-222)(TCNQ)]. A spectrophotometric method for determination of K-222 was developed and validated for the quantitative analysis of K-222 in the radiopharmaceuticals. With an internal standard, the limit of quantitation for K-222 was 2 ug/ml. This is so far the most facile method for the determination of K-222. Excellent linearity (RSQ = 0.9997) was obtained over the range of 2.0–31 ug/ml. Good precision and accuracy were also observed. The method is amenable to the validation of radiosynthetic methods.