Determination of polymeric hindered amine light stabilizers in polyolefins by high-performance liquid chromatography

Abstract

Thin-layer and high-performance liquid chromatography procedures were used for the identification and quantitative determination of the polymeric hindered amine light stabilizers Chimassorb 944 and Cyasorb UV 3346 in polyolefins. After extraction from the polymer by the appropriate solvents, the hindered amine light stabilizers solution was qualitatively tested by thin-layer chromatography and successively analysed with a separation technique described as size-exclusion non-aqueous reversed-phase chromatography using traditional high-performance liquid chromatography equipment. The stationary phase was a non-polar styrene—divinylbenzene copolymer. The mobile phase was tetrahydrofuran containing diethanolamine. Both hindered amine light stabilizers were eluted at times ranging from 10 to 19 min and detected by UV at 239 nm, also showing a specific molecular mass distribution of their telomers. Interference due to other stabilizers was determined by a second elution of the same extraction solution after selective treatment on silica-gel cartridge.