[Simultaneous photometric determination of covalently bound fluorine and fluoride ion contamination adsorbed on drugs in the low ppm range after alkaline pulping]. / Simultane photometrische Bestimmung von kovalent gebundenem Fluorund Arzneistoffen anhaftender Fluoridkontamination im ppm-Bereich nachalkalischem Aufschluss.

The simultaneous determination of fluorine resulting from inorganic fluoride as well as fluorine-containing solvents adsorbed to drugs was achieved in the 0.1-30 ppm range by a combination of decomposition with magnesium oxide at 800 degrees C and steam distillation of the resulting fluoride followed by photometric measurement of the aminomethylalizarindiacetic acid-cerium(III) complex at 620 nm. The inevitable loss of fluoride occurring during the decomposition and distillation processes was corrected using factors derived from authorized calibrations. The method was validated using glucose contaminated with dexamethasone which contains 4.84% fluorine per molecule.