[Analysis of C4 fluoride compounds in alkylation materials by gas chromatography/flame ionization detection (GC/FID)]

A method for the analysis of C4 fluoride compounds in alkylation materials was developed by GC/FID. In order to confirm the presence of C4 fluoride compounds in alkylation materials, 1-fluorobutane, 2-fluorobutane and 2-fluoro-2-methylpropane were synthesized and analysed by GC/FID, gas chromatography/atomic emission detection (GC/AED) and gas chromatography/mass spectrometry (GC/MS). The results showed that only 2-fluoro-2-methylpropane existed in the alkylation materials. Based on the properties of element response on GC/AED, the calibration factors of C4 fluoride compounds on GC/FID were calculated. The analysis was performed on OV-225 (50 m x 0.25 mm i. d. x 0.25 microm) and SE-54 (44 m x 0.22 mm i. d. x 0.25 microm) columns, which were connected in series. FID was used as the detector. In quantitative analysis of the alkylation materials the methods of calibration normalization and indirect external standard were suggested. The calibration curves were linear (r = 0.992) in the concentration range of 156 - 700 microL/L. The minimum detection limit of 2-fluoro-2-methylpropane in real samples was 150 microL/L (S/N = 3). The method is simple, reproducible and easy to be applied. The other components in the alkylation materials can also be analyzed if the calibration normalization method is used.