Figure 4. Fluorescent and radioactive purity of the final compound c was >98%.
HPLC traces of all 5 final products c: G6-(Bz-DTPA)119-(NIR)4-(Bz-DTPA-111In)1 (NIR dyes, a: Cy5, b: Alexa660, c. Alexa680, d: Alexa700, e. Alexa750) obtained with a fluorescence detector are shown. All peak retention times of 5 compounds are 20.67 min on the size-exclusion HPLC using a TSK G6000PW column. Since the fluorescence detector was less sensitive for Alexa750 resulted in small peaks, another HPLC trace of G6-(Bz-DTPA)119-(Alexa750)4-(Bz-DTPA-111In)1 obtained with a radioactivity detector are shown. The peak retention time of this compound is 7.31 min on the size-exclusion HPLC using a TSK G3000PWxL column. The other 4 compounds showed identical radioactive HPLC traces and exactly the same retention time.