Synthesis of 18F-labeled phenolphthalein and naphtholphthalein.
The fluorination of phenolphthalein and naphtholphthalein was performed with diluted fluorine gas under acidic conditions. For both compounds we observed an electrophilic fluorination into ortho position to the hydroxyl group. Through the use of this reaction we synthesized and characterized mono-and difluorinated derivatives of phenolphthalein and naphtholphthalein. The compounds were also prepared in the 18F labeled form, which are usable as a new type of probe for in vivo pH measurement in biological objects using Cerenkov imaging or combination of light absorption and PET.
A Comparative Electrochemical-Ozone Treatment for Removal of Phenolphthalein
The degradation of aqueous solutions containing phenolphthalein was carried out using ozone and electrochemical processes; the two different treatments were performed for 60 min at pH 3, pH 7, and pH 9. The electrochemical oxidation using boron-doped diamond electrodes processes was carried out using three current density values: 3.11 mA·cm−2, 6.22 mA·cm−2, and 9.33 mA·cm−2, whereas the ozone dose was constantly supplied at  mgL−1. An optimal degradation condition for the ozonation treatment is at alkaline pH, while the electrochemical treatment works better at acidic pH. The electrochemical process is twice better compared with ozonation.
Is there a future for clinical fluorine-18 radiopharmaceuticals (excluding FDG)?
Merely, asking this question, which as posed by the Editor-in-Chief, implies that it cannon easily be answered with a simple yes or no. in fact, it is closely related to the question, Is there a future for clinical PET? When looking at the world-wide PET radiopharmaceutical production on the basis of a recent IAEA directory [1], it is disappointing to see that besides FDG, and to a certain extent FDOPA, fluorine-18 radiopharmaceuticals are not widely used. Other 18F products, such as fluoride, spiperone derivatives, FMISO, fluoroaltanserin, fluorofatty acids and fluoroamino acids, are used by only a few centres. The emphasis of this editorial is on clinical radiopharmaceuticals, and in this respect the impact of 18F thus far is extremely small, if on excludes FDG. The reasons are discussed in this editorial.