Fast supercritical fluid extraction of low- and high-density polyethylene additives: Comparison with conventional reflux and automatic Soxhlet extraction

The extraction of antioxidant additives, such as, Irganox 1076 and Irgafos 168, from low-density polyethylene (LDPE) and Irganox 1010 and Irgafos 168 from high-density polyethylene (HDPE) was carried out by supercritical fluid extraction (SFE) working in constant pressure, conventional reflux, and automatic Soxhlet system (Soxtec). Recoveries and repeatability of the evaluated methods, using LDPE and HDPE reference materials, showed some differences between them, but more significant differences were found with features such as sample-processing and time required, which are both crucial for the exploitation of these techniques for quantification in routine industrial quality analysis for additives. SFE was found to be the most advantageous technique in terms of simplicity, cost-effectiveness and speed in comparison to conventional reflux and Soxtec procedures.