Simultaneous Determination of Palladium and Platinum by On-Line Enrichment Followed by Rapid Column High Performance Liquid Chromatography

In this paper, a new method for the simultaneous determination of palladium and platinum ions was developed using a rapid column high performance liquid chromatograph equipped with an on-line enrichment technique. The palladium and platinum ions were pre-column derivatized with 5-(p-aminobenzylidene)-thiorhodanine (ABTR) to form colored chelates. The Pd-ABTR, Pt-ABTR chelates can be absorbed onto the front of an enrichment column when they were injected into the injector and sent to the enrichment column [ZORBAX Stable Bound, 4.6 × 10 mm, 1.8 μm] with a buffer solution of 0.05 mol/L sodium acetate-acetic acid buffer solution (pH 3.5) as mobile phase. After the enrichment had finished, by switching the six-ports switching valve, the retained chelates were back-flushed by mobile phase and traveled towards the analytical column. These chelates separation on the analytical column [ZORBAX Stable Bound, 4.6 × 50 mm, 1.8 μm] was satisfactory with 65% methanol (containing 0.05 mol/L of pH 3.5 sodium acetate-acetic acid buffer salt and 0.01 mol/L of tritonX-100) as mobile phase. The palladium and platinum were separated completely within 2 min. The detection limits (S/N = 3) of palladium and platinum are 1.4 ng/L and 1.6 ng/L, respectively. This method was applied to the determination of palladium and platinum in water and urine samples with good results.