Determination of Halogens in Cardboard Gaskets Using Pyrohydrolysis

A homemade pyrohydrolysis system was developed with modifications of the reactor and condenser for the analysis of cardboard gaskets to determine fluorine, chlorine, bromine, and iodine. A special device was constructed for introducing the sample boat into the reactor. A considerable reduction of the time required for sample preparation was achieved with these modifications. The pyrohydrolysis conditions were optimized to include a reactor temperature of 1000°C, a reaction time of 7.5 min, a sample of 300 mg, a water flow of 1.0 mL/min, and a gas flow rate of 0.2 L/min. It was observed that the accelerator and absorbing solution were not necessary when the temperature of the condensing system was near 0°C. The limits of quantification for 300 mg of sample and a final volume of 15 mL were 12, 1.5, 0.06, and 0.002 µg/g for fluorine, chlorine, bromine, and iodine, respectively. Fluorine was determined with an ion-selective electrode, chlorine by ion chromatography, and bromine and iodine by inductively coupled plasma mass spectrometry. The relative standard deviation was lower than 10% for five replicate analyses of the sample. The developed pyrohydrolysis system was suitable for the routine determination of halogens in cardboard gaskets.