[Simultaneous photometric determination of covalently bound fluorine and fluoride ion contamination adsorbed on drugs in the low ppm range after alkaline pulping].

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.