antioxidants and light-stabilisers

A scheme was devised for the identification of 22 common antioxidants and light-stabilisers in polyolefins. The separation of these stabilisers was performed by isocratic reversed phase high-performance liquid chromatography on a RP-18 column. Three different separation conditions have been used: the mobile phase composition was 100% acetonitrile (MeCN), 90/10 meCN/H₂O and 80/20 MeCN/H₂O. The UV₂₅₄/UV₂₈₀ ratio and the elution time of each stabiliser were determined for these three mobile phase compositions. The values of UV₂₅₄/UV₂₈₀ ratios may be used together with the retention time values for the identification of unknown stabilisers in polyolefin samples.