SIMULTANEOUS INDEPENDENT ANALYSIS OF ANIONS AND CATIONS USING INDIRECT PHOTOMETRIC CHROMATOGRAPHY

An operating mode of ion chromatography is described that generates simultaneous yet fully independent chromatograms of anions and cations using a single detector. Uncoupling the chromatograms yields added sample information without introducing adjacent peak interference or requiring an entire second chromatograph. Keys to the method are dual wavelength uv detection, a copper o-sulfobenzoate eluent, and indirect photometric detection. Since eluent anion and cation exhibit different characteristic UV absorbances at the two detection wavelengths, a ratioing technique permits independent monitoring of eluent anion and cation.