Analysis of Tetramethyl Ammonium Ion by High Performance Liquid Chromatography-Indirect Ultraviolet Detection Using Ionic Liquids as Mobile Phase

• Published in: Fēnxī huàxué 2011-08, Vol.39 (8), p.1251-1255
• Main Authors: Dong, Ying-Jie, Yu, Hong, Wang, Jing-Fei, Huang, Xu
• Format: Article
• Language: chi ; eng
• Subjects: Acetonitrile; Chromatography; Ionic liquids; Linearity; Methyl alcohol; Separation; Ultraviolet; Wavelengths
• ISSN: 0253-3820
• DOI: 10.3724/SP.J.1096.2011.01251

A method was developed for the determination of tetramethyl ammonium ion by reversed phase high performance liquid chromatography with indirect ultraviolet (UV) detection. Chromatographic separation was performed on a ZORBAX ODS reversed phase column using ionic liquids + organic solvents (acetonitrile or methanol) as mobile phase. Chromatographic detection was carried out by indirect UV detection. The effects of the ultraviolet detection wavelength and mobile phases on the separation and determination of tetramethyl ammonium ion were investigated. The optimized chromatographic conditions for the determination of tetramethyl ammonium ion were as follows: 80% 1-ethyl-3-methyl-imidazolium tetrafluoroborate aqueous solution (0.5 mmol/L, pH 3.5 adjusted with acetic acid) + 20% acetonitrile as mobile phase, detection wavelength 210 nm, column temperature 30 degree C, flow rate 1.0 mL/min. Under these conditions, the detection limit (S/N=3) of tetramethyl ammonium ion was 2.60 mg/L. The relative standard deviations (RSD) of the chromatographic retention time and peak areas for tetramethyl ammonium ion were 0.04% and 0.3% (n=5), respectively. The calibration curve showed good linearity over the tested range from 10 to 204 mg/L for tetramethyl ammonium ion concentration with the correlation coefficients of 0.9999. The method has been applied to the determination of tetramethyl ammonium ion in ionic liquid tetramethyl ammonium bromide. The recovery of tetramethyl ammonium ion after spiking was 99.3%.