| In this paper,a new method of imidazolium ionic liquids applied to reversed-phase chromatography mobile phase additives to detect 5 kinds of food additives was developed.The purpose is to develop a new method for fast,simple,accurate and reliable analysis of food additives,expand the application of ionic liquids,and provide new analysis methods for the detection of food additives in actual samples.The main contents of this paper are as follows:1.In this work,the study of imidazolium ionic liquids used in the mobile phase for analysis of benzoic acid and sorbic acid in reversed-phase chromatography was carried out.The effects of imidazolium ionic liquid,organic solvent methanol and other factors on the retention time of benzoic acid and sorbic acid were studied,and the retention rules of the two analytes were discussed.A new analytical method for the determination of benzoic acid and sorbic acid by reversed-phase chromatography with imidazolium ionic liquid as mobile phase additive was established.Used Agilent ZORBAX ODS reverse phase chromatography column,methanol/0.2 mmol/L1-butyl-3-methylimidazolium chloride aqueous solution(40/60,v/v)as mobile phase,detection wavelength of 230 nm,flow rate 1.0 m L/min,the column temperature was35 ℃,under these chromatographic conditions,benzoic acid and sorbic acid were separated well within 7 min.The LOD values of the two substances to be tested were0.02 mg/L.The method was applied to the determination of benzoic acid and sorbic acid in beverage samples in the market,the recovery rate of standard addition of benzoic acid and sorbic acid were 93.9%-103.9% and RSD was less than 4.0%,which met the requirements of quantitative analysis.2.In this work,imidazolium ionic liquid were used as mobile phase for the analysis of tyrosine and phenylalanine in reversed-phase chromatography.The effects of imidazolium ionic liquid as mobile phase additive on the separation of tyrosine and phenylalanine were studied.The effects of alkyl chain length of imidazolium ionic liquid cation,methanol concentration of organic solvent and other factors on the separation and detection of tyrosine and phenylalanine were investigated,and the retention rules and mechanism of the two analytes were discussed.An analytical method for the determination of tyrosine and phenylalanine by reversed-phase chromatography with imidazolium ionic liquid as mobile phase additive was established.When using Agilent ZORBAX ODS reverse phase chromatography column,methanol/0.1 mmol/L 1-hexyl 3-methylimidazolium chloride aqueous solution(15/85,v/v)is used as mobile phase,detection wavelength of is 200 nm,flow rate is1.0 m L/min,the column temperature was 35 ℃,the separation and detection of tyrosine and phenylalanine were achieved within 7 min.The LOD values of the two substances to be tested were both lower than 0.25 mg/L.The method was applied to the determination of tyrosine and phenylalanine in bread food additives and beverage samples.The recovery rate of standard addition was 95.9%-103.40%,and RSD was less than 0.9%,which met the requirements of quantitative analysis.3.In this work,a new analytical method for the analysis of choline chloride by indirect ultraviolet detection using imidazolium ionic liquids as mobile phase additives in reversed-phase chromatography was developed.The effects of different kinds of ionic liquids as mobile phase additives on the separation of choline chloride and tetramethylammonium bromide were studied respectively,and the retention rules and mechanisms of the two analytes were described.used Agilent ZORBAX ODS reversed phase chromatography column,methanol/0.2 mmol/L 1-butyl-3-methylimidazolium tetrafluoroborate aqueous solution(30/70,v/v)is used as mobile phase,detection wavelength 210 nm,flow rate at 1.0 m L/min and the column temperature of 30 ℃,the separation and detection of choline chloride and tetramethylammonium bromide were achieved within 15 min.The detection limits of choline chloride and tetramethylammonium bromide were both lower than 0.01 mg/L.The method was applied to the determination of choline chloride in plant growth regulators,the recovery rate of standard addition was 96.67%-99.92%,and RSD was less than 0.9%,which met the requirements of quantitative analysis. |
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