Analysis of Perfluoro-carboxylic Acid Fluorides by Gas Chromatography/Mass Spectrometry

The perfluoro-carboxylic acid fluorides prepared by electrochemical perfluorination(ECPF) method were analyzed by gas chromatography/mass spectrometry.Methanol was used to convert the perfluoro-carboxylic acid fluorides into the methyl esters at 60 ℃.The effects of column length,polarity and film thickness on the separation efficiency were investigated.The KB-1MS capillary column(90 m × 0.25 mm × 1.0 μm) was employed in the GC/MS analysis.The fragmentation patterns and mass spectrometric characteristics of perfluorinated alicyclic acid methyl esters,aliphatic carboxylic acid methyl esters and mono-unsaturated perfluorinated aliphatic carboxylic acid methyl esters were analyzed and deduced from known patterns of perfluoro-organic mass spectrometry.In this work,five perfluoro-carboxylic acid fluorides including two isomers were identified and the perfluorocyclohexylcarboxylic acid fluoride accounted for about 65%of the total perfluoro-carboxylic acid fluorides in the product.