A Distinct Anion Separation Approach via Isocratic Liquid Chromatography Coupled with Vacuum Ultraviolet Detection

Analytical methods to perform chromatographic separation of 36 common inorganic and organic anions were developed using non-suppressed ion chromatography. The separation utilized highly stable uncharged cyclofructan-based stationary phases and mobile phases consisting of varying ratios of acetonitrile and dilute perchlorate salts in water. Optimal separations occurred in hydrophilic interaction liquid chromatography (HILIC) mode. Detection was performed using a novel detector: vacuum ultraviolet (VUV) detection for liquid chromatography. VUV detection is well-suited for the detection of anions, many of whose absorption spectra typically fall below the lowest wavelengths collected by standard ultraviolet detectors. VUV detection is nondestructive, provides qualitative spectral information, and can be coupled with other detectors. Twenty-seven anions were separated using an acetonitrile/aqueous potassium perchlorate mobile phase, and an additional nine anions were separated with lithium perchlorate in the mobile phase which adjusted retention via electrostatic selectivity modulation.