For my protocol, at end-point I have to do tail-vein injections of TRITC-labeled dextran (100 ml of 10 mg/ml) and FITC-labeled lectin (50 mg). However, the protocol I'm following states that they inject one, followed by a 10 min circulation and then the other followed by a 5 min circulation. Tail-vein injections on black mice can be challenging especially two. I know some fluorescence reagents can be mixed but I just want to confirm this can be done.