Rapid characterization of commercial polysorbate 80 by ultra-high performance supercritical fluid chromatography combined with quadrupole time-of-flight mass spectrometry

•Novel and efficient UHPSFC-QTOF-MS method was developed to characterize the polysorbate 80.•UHPSFC-QTOF-MS could distinguish n-mer from (n − 1)-mer and (n + 1)-mer, which provided the high separation resolution needed for quantifying each oligomer in the same series.•The characteristic ion fragments were found in MS/MS experiment and used to identify different series.•The relationship between molecular structure of different oligomers and retention behavior in supercritical fluid chromatography were investigated.

Polysorbate 80, as a nonionic surfactant, is widely used in the food, personal care, and pharmaceutical industries due to the advantages of high surface activity, low toxicity, etc. In fact, the products of polysorbate 80 are complex mixtures of oligomers. In this work, a novel and fast method was developed to characterize the commercial polysorbate 80 by ultra-high performance supercritical fluid chromatography (UHPSFC) combined with quadrupole time-of-flight mass spectrometry (QTOF-MS). Some crucial parameters, such as temperature, back pressure and flow rate were optimized. UHPSFC could distinguish n-mer from (n − 1)-mer and (n + 1)-mer in the same series, which provided the high separation resolution needed for quantitative determination of each oligomer in same series. It was not achieved in previous studies. Furthermore, the characteristic ion fragments were found in MS/MS experiment and used to identify different series. The results revealed that main components of this nonionic surfactant comprise polyethylene oxide (PEO), PEO-monooleate, PEO-isosorbide, PEO-isosorbide monooleate, PEO-isosorbide dioleate, PEO-sorbitan, PEO-sorbitan monooleate, PEO-sorbitan dioleate and PEO-sorbitan trioleate, etc. The separation was performed using BEH stationary phase, so the relationship between molecular structure of these oligomers and chromatographic retention behavior in supercritical fluid chromatography were also investigated for first time. The whole analytical process only takes 8 min for one sample. Therefore, UHPSFC-QTOF-MS is a simple, novel and efficient tool to analyze polysorbate 80.