Determination of inorganic anions by photometric ion chromatography: use of a popular ion exchange column and a conventional high performance liquid chromatograph

A photometric determination method of microamounts of inorganic anions has been developed by conventional high performance liquid chromatography using a popular ion exchange column. Inorganic anions (HCO3-, Cl-, NO2-, H2PO4-, Br-, NO3-, SO42-, and I-) were separated on an anoin exchange column by using disodium phthalate solution as an eluent, and detected as troughs in the base line absorbance by a UV monitor. The optimum conditions for the determination of HCO3-, Cl-, H2PO4-, Br-, NO3-, and SO42- were as follows: column, Zipax SAX (2.1 mm i.d.×50 cm) ; eluent, 5×10-4 M disodium phthalate;flow rate, 1 ml/min; column temperature, ambient;detection wavelength, 240 nm. Under the conditions described above, detection limits of these anions were at levels as low as ppb. The calibration curves gave straight lines by either peak height or peak area method. Main inorganic anions contained in environmental samples could be simultaneously determined by the proposed method, and their analytical results were close to those obtained by other methods.