Authors:R. Soomro, S. Q. Memon, M. J. Ahmed, N. Memon, and A. Mallah
Bis(salicylaldehyde) orthophenylenediamine (BSOPD) is reported here as a complexing reagent for simultaneous determination of six metal ions, gold, chromium, iron(II)/(III), uranyl, and nickel, by capillary zone electrophoresis. The pre-derivatized complexes were injected onto 50 cm bare silica capillary (i.d. 75 µm) with background electrolyte 50 mM citrate:oxalate buffer in 1:1 at pH 4. All metal ions were separated within 15 min including coexisted ions at applied voltage of −15 kV at detection wavelength of 250 nm. Under the abovementioned conditions, limits of quantification and detection were found to be 0.5, 1.0, 1.0, 10.0, 1.0, and 10.0 µg mL−1; and 0.16, 0.33, 0.33, 3.33, 0.33, and 3.33 µg mL−1 for Au(III), Cr(VI), Fe(III), Fe(II), UO2(II), and Ni(II), respectively. Linear calibration graphs were obtained in the ranges of 0.5–100, 1–200, 10–100, 1–100, 1–100, and 10–200 µg mL−1 with the correlation coefficient values 0.9964, 0.9948, 0.9900, 0.9999, 0.9992, and 0.9918 for Au(III); and Cr(VI), Fe(III), Fe(II), UO2(II), and Ni(II), respectively. Applicability of the method has been evaluated by determining gold from wastewater samples of goldsmith factories and uranyl from ore samples. The developed method was also used for the determination of chromium in selected environmental waters (drinking and polluted). The data obtained with developed method were compared with those obtained from atomic absorption spectroscopy, and the results of the analysis were found to be in good agreement.