Characterization of polyethermethylsiloxanes using ultra-high performance liquid chromatography-electrospray ionization and time-of-flight mass spectrometry

Changna Yin; Jie Fu; Xiuyang Lu

doi:10.1016/j.aca.2019.07.041

Characterization of polyethermethylsiloxanes using ultra-high performance liquid chromatography-electrospray ionization and time-of-flight mass spectrometry

Anal Chim Acta. 2019 Nov 15:1082:194-201. doi: 10.1016/j.aca.2019.07.041. Epub 2019 Jul 24.

Authors

Changna Yin¹, Jie Fu², Xiuyang Lu¹

Affiliations

¹ Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China.
² Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China. Electronic address: jiefu@zju.edu.cn.

PMID: 31472709
DOI: 10.1016/j.aca.2019.07.041

Abstract

Polyethermethylsiloxanes (PEMSs) are silicone based polymers formed by attaching one or more ethylene oxide (EO)/propylene oxide (PO) chains to a siloxane chain. As the siloxane chain is lengthened, the polarity of the PEMSs are reduced. Little research has been conducted on the use of ultra-high performance liquid chromatography (UHPLC)-mass spectrometry (MS) to analyze PEMS oligomers with more than 4 siloxane groups because of their low polarity and poor solubility in water and acetonitrile (ACN). In this study, we developed a high chromatographic resolution method for PEMS and polyether oligomers using the water-ACN-isopropanol (IPA) tertiary solvents gradient. PEMSs oligomers containing one EO pendant chain and 3-13 silicone groups were analyzed. More than 102 PEMS oligomers and 21 polyether oligomers were separated within 45 min and identified by accurate molecular masses. During this gradient elution process, different chromatographic modes were used: both precipitation-redissolution and adsorption mode for PEMSs, adsorption mode for EO chains in polyethers, and exclusion mode for EO chains in PEMSs. This efficient separation method for PEMSs would broaden the characterization of silicone surfactants. Also, it is beneficial to establish the relationship between surfactant structure, synthetic route and performance optimization.

Keywords: Collision-induced dissociation (CID); Critical adsorption point (CAP); Exclusion-adsorption chromatography; Polyethermethylsiloxanes (PEMSs); Precipitation-redissolution chromatography; Reversed-phase ultra-high performance liquid chromatography (RP-UHPLC); Time-of-flight mass spectrometry (TOFMS).