A Fast and Simple Method for the Determination of TBA in ¹⁸F-Labeled Radiopharmaceuticals

A simple color spot test for determining the presence of residual tetrabutylammonium (TBA) in various ¹⁸F-radiopharmaceuticals is described. The test can be performed in less than five minutes. Iodoplatinate-saturated TLC plates are initially spotted with the ¹⁸F-radiopharmaceutical to be tested and TBA, then with deionized water or hydrogen peroxide (H₂O₂) solution, depending on if an antioxidant stabilizer is part of the pharmaceutical matrix. A distinct brown spot is visible at TBA concentrations of 50 µg/mL and up.