Use of Ionic liquids as additives in ion exchange chromatography for the analysis of cations

A novel approach for the simultaneous separation and indirect ultraviolet detection of chlorate and perchlorate using pyridinium ionic liquids as mobile phase additives in reversed-phase liquid chromatography was developed. Pyridinium ionic liquids and imidazolium ionic liquids as the mobile phase additives were compared. The effects of pyridinium ionic liquids, methanol, column temperature, and detection wavelength on the separation and detection of chlorate and perchlorate were investigated. The role of ionic liquids, retention rules and relevant mechanisms were discussed. Pyridinium ionic liquids mainly acted as ultraviolet absorption reagent and ion-pair reagent. The successful separation and indirect ultraviolet detection of chlorate and perchlorate were achieved by using a common reversed-phase column, 0.2 mmol/L N-octylpyridinium bromide aqueous solution/methanol (90/10, v/v) as mobile phase and at the detection wavelength of 210 nm. The retention times of chlorate and perchlorate were 30.51 and 37.06 min, respectively. The detection limits of chlorate and perchlorate were 0.16 and 0.29 mg/L, respectively. The linearity and repeatability of the method were satisfactory. The approach was used to the analysis of river water samples with accurate and reliable results. This method is easy to popularize due to the use of common reversed-phase column and ultraviolet detector in liquid chromatography.

Section: Introductionmentioning

confidence: 99%

Simultaneous separation and indirect ultraviolet detection of chlorate and perchlorate by pyridinium ionic liquids in reversed‐phase liquid chromatography

Yin

Zhang

Guan

et al. 2020

“…In recent years, the applications of ILs in the fields of GC stationary phases [12], LC stationary phases [13][14][15][16][17][18] and mobile phase additives [19,20] have received increasing attention. There are some reports on the analysis of organic substances such as alkaloids [21][22][23][24][25] and metal ions [26][27][28] by using ionic liquids as mobile phase additives, but there are few reports on the analysis of anions [29,30] which needs to be further studied extensively.…”

Section: Introductionmentioning

confidence: 99%

Ionic liquids as mobile phase additives for determination of thiocyanate and iodide by liquid chromatography

Cui

2019

An analytical method was developed for the simultaneous determination of thiocyanate and iodide by reversed‐phase liquid chromatography with UV detection using imidazolium ionic liquids as mobile phase additives. The chromatographic behaviors of the two anions on a C18 column were studied and compared with four types of reagents including imidazolium ionic liquids, pyridinium ionic liquids, 4‐aminophenol hydrochloride and tetrabutylammonium as mobile phase additives. The effects of the concentrations of imidazolium ionic liquids, organic solvents and detection wavelength on separation and detection of the anions were investigated. The role of ionic liquids, retention rules and mechanisms were discussed. The separation of the anions was performed on the C18 reserved‐phase column using acetonitrile‐0.3 mmol/L 1‐amyl‐3‐methylimidazolium tetrafluoroborate (10:90, v/v) as mobile phase, with column temperature of 35°C, flow rate of 1 mL/min and detection wavelength of 210 nm. Under these conditions, the two anions can be completely separated within 6 min. The limits of detection were 0.05 mg/L. The method was applied for the determination of thiocyanate and iodide in ionic liquid samples and iodide drugs, and the spiked recoveries ranged from 97 to 101%. The method is simple, accurate and meets the requirements of quantitative analysis for thiocyanate and iodide.

“…In recent years, ILs have attracted increasing attention in the field of chromatographic analysis, and their applications include GC stationary phases , LC stationary phases , and mobile phase additives . Up to now, the main substances analyzed by using ILs as the mobile phase additives of LC are organic substances such as alkaloids , some cations , and anions . Pyridinium and imidazolium ILs have strong UV absorption, which can be used as UV absorption reagents for IUV detection .…”

Section: Introductionmentioning

confidence: 99%

Separation and indirect ultraviolet detection of ferrous and trivalent iron ions by using ionic liquids in ion chromatography

Wen

2019

A method of simultaneous separation and indirect ultraviolet detection of different valence iron ions Fe2+ and Fe3+ by using ionic liquids as mobile phase additives and ultraviolet absorption reagents on a cation exchange column functionalized with carboxylic acid group was developed. The effects of ionic liquids, organic acids, detection wavelength, etc. on separation and detection of Fe2+ and Fe3+ were investigated and the mechanism was discussed. The pyridinium and imidazolium ionic liquids were not only ultraviolet absorption reagents of indirect ultraviolet detection but also effective components for separating Fe2+ and Fe3+. The separation and detection of Fe2+ and Fe3+ can be achieved using 0.5 mmol/L pyridinium ionic liquid−1.2 mmol/L methanesulfonic acid as the mobile phase. The determination of Fe2+ and Fe3+ had a good linear relationship in the concentration range of 1−100 mg/L. The limits of detection of Fe2+ and Fe3+ were 0.12 and 0.09 mg/L, respectively. This method was applied to the actual sample detection in the field of medical analysis. The spiked recoveries were between 97.3 and 99.5%, and the relative standard deviations were less than 0.6%. The method is simple, accurate, and reliable, and is an analytical method with universal and practical value.