High-sensitivity conductivity detection in non-suppressed ion chromatography using sulfoisophthalic acid as eluent

A non-suppressed ion chromatographic (IC) system for the high-sensitivity detection of common anions was developed using sulfoisophthalic acid as the eluent. The detection sensitivity was ten times higher than that using conventional non-suppressed IC with sodium phthalate as eluent, and was almost the same as that using conventional suppressed IC with a carbonate-hydrogencarbonate eluent under the same electrical conditions with a conductivity detector. Temperature regulation was very important in minimizing the baseline drift. A commercial incubator, in which a separation column and a sample injector were placed, was useful. The developed non-suppressed system facilitated the determination of low concentrations of phosphate, chloride, bromide, nitrate and sulfate at micromolar levels.