The Optimization and Validation of a Method for Sb Determination from PET by ICP-OES

In the present work it was developed a simple, cheap and quick method for Sb determination from PET in the 10-500 mg Kg(-1) concentrations range, using an original digestion method coupled with the ICP-OES technique. The digestion method, developed and optimized for this study, uses a single digestion reagent (HNO3), adequate the measurement equipment. It ensures a reduced digestion time (45 min.), thus having small energy consumption (0.15 KWh/sample) and uses standard digestion equipment. On the studied concentration range the method presents the following characteristics the calibration curve slope, expressed through correlation coefficient r = 0.9999, standard deviation of repeatability of 1.27 mg Kg(-1), RSD = 0.49 %, accuracy determined by recovery degree ranges between 85 % and 96 %, all being comparable with literature data. The value of extended uncertainty is 8.4 mg Kg(-1) with a confidence level of 95 % (k=2), obtained for Sb content of 259.6 mg Kg(-1). The applicability of the method can be extended with the same digestion method and adequate modification of the concentration range for the calibration curve. The validated method for antimony content from PET cans can be applied in various research studies.