Extraction and quantification of antioxidants from low-density polyethylene by microwave energy and liquid chromatography

In this paper a experimental design is applied to optimize the quantification of hindered phenol Irganox 1076, phosphite antioxidant Irgafos 168 and their oxidized product tri[2,4-di-tert-butylphenyl]phosphate from low-density polyethylene (LDPE). The developed analytical method consists of two steps: microwave-assisted extraction and reversed-phase liquid chromatography (LC) coupled with ultraviolet diode-array detector. A Plackett–Burman design was carried out in order to find the significant experimental parameters affecting the antioxidants extraction by microwave energy. These parameters were subsequently optimized by a central composite design. The performed method allows extracting the studied antioxidants at low temperature in a short time without degradation of phosphite antioxidant Irgafos 168.