Abstract
Antimony in fire retardant polypropyrene could be extracted into boiling HCl (6N) layer from xylene layer containing dispersed sample and antimony content was determined by atomic absorption spectrophotometry. The outline of the extraction method was as follows: 250 mg of sample was taken into a Kjeldahl flask connected with a reflux condenser. 20 ml of xylene was added and heated gently. 30 ml of HCl was then added and the mixture was heated with boiling state for 30 minutes. The HCl layer was filtered through a filter paper to a volumetric flask after cooling. By repeating the extraction with HCl twice, more than 99% of antimony was extracted. The conditions for atomic absorption were : wavelength 2175.8 Å, lamp current 17 mA, burner height 10 mm, air flow-rate 7.0 1/min, acetylene flow-rate 1.5 1/min and entrance slit width 0.1 mm. A linear calibration curve was obtained within the concentration range of 0 to 75 ppm for antimony. No appreciable interference was caused by other elements likely to be present in sample. The coefficient of variation for a sample containing 7.70% Sb2O3 by the present method was 2.30%.
