Differences of fluorine in cements determined by photometric methods after distillation and pyrolysis

Using a spectrophotometric method after distillation separation is a standard test method widely employed for the determination of fluorine (F) in cement. Using a flow injection (FI) method after pyrolysis separation for quantification of fluorine in cement has recently been developed. Differences between the fluorine content values obtained by each method have been noted. This paper documents the differences between fluorine content (distillation F) measured spectrophotometrically after distillation and that (pyrolysis F) determined using the FI method after pyrolysis for fourteen commercial Portland cements and identifies a factor contributing to the differences between distillation F and pyrolysis F values. A highly significant relationship existed between distillation F and pyrolysis F values for fourteen cements (r(2) = 0.998, p < 0.001).