3.4.2. Protein Binding

The ability of the <sup>68</sup>Ga-labeled conjugates to bind to serum proteins was determined by size exclusion chromatography. Aliquots (50 µL, *n* = 3) of the radioligand solution (~10 µM) were incubated in 450 µL freshly prepared human serum as well as 450 µL PBS as control and the mixtures were maintained at 37 ◦C. After 1, 2, and 4 h, aliquots (25 µL) were transferred to illustra MicroSpin G-50 columns (GE Healthcare Vienna, Austria) and the percentage of protein-bound (eluate) and non-bound (column) conjugate was calculated.
