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Ultra‐high performance supercritical fluid chromatography combined with quadrupole time‐of‐flight mass spectrometry for the characterization of pentaerythritol fatty acid esters
Author(s) -
Tang Yan,
Pan Jinheng,
Sun Tangqiang,
Hu Yajing,
Du Zhenxia
Publication year - 2020
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.8664
Subject(s) - pentaerythritol , chemistry , mass spectrometry , pentaerythritol tetranitrate , fatty acid , chromatography , organic chemistry , fire retardant , explosive material
Rationale Pentaerythritol fatty acid esters are an excellent lubricant oil additive, due to their good biodegradability, thermal ability, anti‐wear, and friction properties. However, to meet the application requirements, fatty acids with different alkyl chain lengths are reacted with pentaerythritol, resulting in complex ester compositions. To reveal the relation between the functionalities and the composition of esters, it is important to develop a method for their analysis. Methods We developed a method using ultra‐high‐performance supercritical fluid chromatography combined with quadrupole time‐of‐flight mass spectrometry (UHPSFC/QTOF‐MS) to separate and characterize pentaerythritol fatty acid esters. This method has the advantages such as short analysis time and high separation efficiency for such weakly polar compounds; high‐resolution mass spectrometry (HRMS) provides exact mass information, enabling the identification of the structure of the pentaerythritol fatty acid esters. Results Based on the exact masses and characteristic ions, the pentaerythritol fatty acid esters and their main fragmentation pathways were identified; the fatty acid composition was also deduced from characteristic product ions. A dihydrogen rearrangement reaction caused the neutral loss of fatty acid fragment; [M + Na‐FA] + product ions (a stable six‐member ring structure) were produced due to the absence of a γ hydrogen in pentaerythritol fatty acid esters. Conclusions A UHPSFC/QTOF‐MS method was successfully employed for the separation of pentaerythritol fatty acid esters. Exact masses and product ion information were determined using HRMS. The composition of the fatty acids was effectively deduced by characteristic ions and their relative abundances. This method is an effective means for the quality control and process optimization of this type of product, serving as a positive reference for further study on pentaerythritol fatty acid esters.