Quantitative analysis of oleic acid and three types of polyethers according to the number of hydroxy end groups in Polysorbate 80 by hydrophilic interaction chromatography at critical conditions

A quantitative characterization of Polysorbate 80 is crucial for its many applications. In this paper we report a quick RP-HPLC method for the quantitative determination of Polysorbate 80. The hydrolysis of Polysorbate 80 to release oleic acid and three types of polyethers was first carried out. A chromatographic method based on liquid chromatography at critical conditions (LCCC) was then developed for an endgroup-based separation of low-molecular-mass polyether. With this method the polyether, irrespective of its molecular-mass, is separated according to endgroups (functionality) due to interactions of the polar endgroups with the hydrophilic stationary phase. The different types of polyethers and oleic acid were identified using on-line electrospray ionization mass spectrometry and quantified by evaporative light scattering detection.

► Separation is an important prerequisite for successful Polysorbate 80 analysis. ► We present a new methodology for Polysorbate 80 analysis. ► A simple and comprehensive method for the analysis of Polysorbate 80 was developed. ► Oleic acid and three types of polyethers were successfully quantified by LCCC/ELSD. ► Column selection for the application of LCCC method are discussed.