Liquid chromatographic methods to analyze hindered amines light stabilizers (HALS) levels to improve safety in polyolefins

A chromatographic method using ultra performance LC with ultraviolet spectrophotometry detection system (UPLC‐UV‐visible (UV/Vis)) (UPLC, ultra performance LC) was developed to determine Chimassorb 944 and Tinuvin 770, high‐ and low‐molecular mass hindered amine light stabilizers, respectively. The use of a bridge ethylene hybrid‐based particles C 18 UPLC column, being compatible with a buffered mobile phase adjusted to pH 11.5, was used to achieve a satisfactory elution of possible non‐ionizated units of polymeric Chimassorb 944. In addition, a HPLC with positive ion mode ESI and hybrid linear ion trap (LTQ) Fourier transform (FT) Orbitrap MS detection system (HPLC‐UV/Vis‐ESI‐LTQ(FT)Orbitrap) was used for screening and identification purposes. Reliable determinations of monomeric units of Chimassorb 944 and molecule of Tinuvin 770 were achieved by HPLC‐ESI(+)‐LTQ FT Orbitrap MS method using scan mode. Quality parameters of UPLC‐UV/Vis method were evaluated. Obtained LODs and LOQs were 3.41 and 11.4 mg/L for Tinuvin 770 and 0.83 and 2.78 mg/L for Chimassorb 944, respectively. Satisfactory quality parameters of this chromatography method provided the chance to count on a good tool to know the compliance with legal requirements.