| In this paper,the detection of inorganic anions by reversed-phase liquid chromatography ultraviolet absorption with ionic liquid as mobile phase was studied.To explore the possibility of using ionic liquid as ultraviolet absorption reagent and eluent to separate and detect inorganic anions by indirect ultraviolet.The purpose is to develop a new simple,accurate,reliable and universal method for the analysis of inorganic anions,and to provide a new reference method for the determination of inorganic anions in actual samples.The main contents of this research are as follows.1.A new method for the determination of F–,Cl–,Br–and I–by reversed-phase liquid chromatography combined with indirect ultraviolet detection was developed.The experimental results of ionic liquid type,alkyl chain length,ionic liquid concentration,organic phase type and concentration,wavelength and temperature on determination of halogen ions in mobile phase were investigated,and the retention law of inorganic anions was discussed.Imidazolium ionic liquid has two main functions as mobile phase additive.On the one hand,imidazolium ionic liquid plays the role of background ultraviolet absorption reagent in indirect ultraviolet detection.On the other hand,imidazolium ionic liquids act as ion pair reagents and combine with F–,Cl–,Br–and I–to form ion pairs,resulting in retention and separation on fixation.Using reversed phase column,and the mobile phase was methanol/0.4 mmol/L1-octyl-3-methylimidazolium tetrafluoroborate aqueous solution（10/90,v/v）,the ultraviolet absorption wavelength was 235 nm,the flow rate was 1.0 m L/min,and the column temperature was 35℃,the four anions were completely separated within 21 min.The detection limits of F–,Cl–,Br–and I–were 0.21,0.2,0.28 and 0.04 mg/L respectively.The standard curve has a good linear relationship.The method was applied to the analysis of potassium chloride medicines and bottled water.The spiked recoveries were between 96.8%and 100%,and the RSD was less than 1.7%.The method is simple,accurate,reliable,and had good accuracy and precision.Meet the requirements of quantitative analysis.2.The analytical method of pyridinium ionic liquid for the determination of NO3–and NO2–by reversed-phase liquid chromatography ultraviolet was developed.The effects of ionic liquid type and concentration,acetonitrile concentration,column temperature and detection wavelength on the determination of NO3–and NO2–were investigated.The mobile phase was acetonitrile/0.3 mmol/L N-octylpyridine tetrafluoroborate aqueous solution（10/90,v/v）,the detection wavelength was 210 nm,and the column temperature was 35°C.Under this chromatographic condition,NO3–and NO2–were detected within 10 min,and the detection limits of NO3–and NO2–were 0.15and 0.16 mg/L.The method was applied to the analysis of drinking water,and the spiked recoveries of NO3–and NO2–were between 97.5%and 104%.The method is simple and accurate,and meet the requirements of quantitative analysis.3.An analytical method for the determination of Cl O3–,Br O3–and IO3–three anions by liquid chromatography indirect ultraviolet was developed.The effects of chromatographic column type,ionic liquid cation type and concentration in mobile phase,organic solvent type and concentration,detection wavelength and temperature and other related factors on the determination of Cl O3–,Br O3–and IO3–were investigated.The mobile phase was acetonitrile/0.5 mmol/L N-octylpyridine tetrafluoroborate saline solution（18/82,v/v）,the detection wavelength was 210 nm and the chromatographic column temperature was 50°C.Cl O3–,Br O3–and IO3–were detected and separated within7 min,and the detection limits of Cl O3–,Br O3–and IO3–were between 0.1,0.06 and 0.04mg/L,respectively.It was found that the common anions SO42–do not interfere with the determination of Cl O3–,Br O3–and IO3–.Applying this method to the detection of tap water samples,the spiked recoveries were between 97.2%and 108.0%,and the RSD was no more than 2%.This method is simple and reliable,and meet the requirements of quantitative analysis. |
