Anion exchange chromatography with both indirect photometric detection (IPD) and unsuppressed conductivity detection modes were used for the separation and detection of inorganic anions. Salt of phthalic acid has been used as an eluent for several anions both with IPD and conductivity detection. Phthalate possess ion-exchange capability, chromatographic selectivity, and large molar absorptivity Phthalate has shown good chromatographic performance toward the analyses of some anions such as (Thiocyanate, Chloride, Bromide, Nitrate and Sulfate) using conventional HPLC equipment with either indirect UV or conductivity detectors. The analysis of these anions using 1.5x10-4M phthalate at pH 5.40 in 10%methanol, AS4A Ion Pack column, 1 mL/min flow rate was achieved. IPD at 228 nm and conductivity detection.Chromatogram of a mixture containing for anions such as (Cl-, Br-, NO3-, SO4-2) and other mixture containing four anions such as (SCN-, Br-, NO3-, SO4-2) have given well separated peaks. The capacity factors (ќ) for the analyzed anions were ranged from (1.71-6.85), peak symmetries was ranged from (0.84-1.48), and resolution with an average value of 3.758 were obtained, which indicate a good chromatographic performance. The RSD in tR averaged 0.736%. The average recovery was 95.14 %, and the relative error percentage was averaged 4.91 % with IPD. However, using unsuppressed conductivity detection, the peak symmetry was ranged from (0.74-1.35), and an average value of resolution of 1.949. The average value of recovery was 92.31 %, and the relative error averaged 7.46 % using conductivity detection.Calibration curve for all analyzed anions were linear from their detection limits at least 25 ppm. The correlation coefficients for the linear calibration curve were ranged from [0.9994-0.9999] with both detection techniques. The detection limit was ranged from (0.1-0.2) ppm using IPD detection compared to (0.15-0.25) ppm with conductivity detection.
