Determination of Main Composition of Fatty Acid Monoglyceride in Monoglyceride Emulsifier Using Ultra Performance Convergence Chromatography-Mass Spectrometry

A fast analytical method was developed for the determination of main composition of fatty acid monoglycerides, including monopalmitin, monostearin, monoolein and monolinolein, in monoglycerede emulsifiers by ultra-performance convergence chromatography-mass spectrometry. Their contents were compared in the 3 emulsifiers from different sources. The sample was directly dissolved with n-hexane/isopropanol (7:3, /V) The chromatographic separation was performed on the ACQUITY UPC2 BEH 2-EP column (2. 1 mm. 100 mm, 1. 7 mu m) using the mobile phases of carbon dioxide and methanol/acetonitrile (1:1, V /V) solution with gradient elution. The separated compounds were detected by MS detector in positive electrospray ionization (ESI+) and quantified by external standard method. The results showed that the calibration curves of monopalmitin, monostearin, monoolein and monolinolein were linear in the range of 0. 20- 50 mg/L, 0. 20 - 50 mg/L, 0. 25-62. 5 mg/L and 0. 20 - 50 mg/L, respectively, with correlation coefficients not less than 0. 9983. The limits of quantification (S/N >= 10) of the four fatty acid monoglycerides were 0. 018- 0. 046 mg/L. The average recoveries for the four monoglycerides at three spiked levels were 88. 0% - 110. 5% with relative standard deviations of 1. 1% - 4. 1%. The proposed method showed high performance, good selectivity and fast analysis for the underivatized monoglyceride samples. It would provide a new chromatographic technology for the content analysis of monoglycerides in the emulsifier.