A novel ion chromatography using a conventional ion exchange column and a photometric detector

A novel method for the determination of micro amounts of inorganic ions has been developed. The separation of alkaline metal ions (Li+, Na+, and K+) was accomplished on a Zipax SCX packed column (4.6mm×12cm) with 2.5×10-4M copper sulfate as an eluent, and the separation of halogen ions (F-, Cl-, and Br-) was accomplished on a Zipax SAX packed column (4.6mm×15cm) with 1.0×10-3M sodium benzoate as an eluent. The eluted ions were detected as troughs in base line absorbance of eluent ion at 220nm or 240nm. Under the conditions described above, the six ions were easily separated and determined at the levels as low as ppb by using either a peak height method or a peak area method. which gave straight calibration curves. Other inorganic ions can be also determined by changing composition and concentration of the eluent. Moreover, this analytical method is economical and simple, since it can be performed with a conventional HPLC system equipped with a single separation column packed with inexpensive and easily available ion exchanger and a photometric detector.