oa South African Journal of Chemistry - Simultaneous determination of palladium and platinum by on-line enrichment and HPLC with 4-(2-hydroxynaphthalene-1-ylmethylene)-thiazolidine-2, 5-dithione as pre-column derivatization reagent
In this paper, a new reagent, 4-(2-hydroxy-naphthalene-1-ylmethylene)-thiazolidine-2, 5-dithione (HNMTD) was synthesized. A new method for the simultaneous determination of palladium and platinum ions as metal-HNMTD chelates was developed using high performance liquid chromatography equipped with an on-line enrichment technique. Prior to chromatography the palladium and platinum ions were derivatized with HNMTD to coloured chelate complexes. The Pd-HNMTD and Pt-HNMTD complexes were then enriched on an enrichment column (ZORBAX Reversed Phase Stable Bound C18, 4.6 x 10 mm, 1.8 µm) using a buffer solution of 0.05 mol L-1 sodium acetate-acetic acid buffer (pH 3.8) as mobile phase. After the enrichment was completed, the retained chelates were back-flushed to the analytical column. The separation of chelates on the analytical column (ZORBAX Reversed Phase Stable Bound C18, 4.6 x 50 mm, 1.8 µm) was satisfactory when 72% methanol (containing 0.05 mol L-1 of pH 3.8 sodium acetate-acetic acid buffer salt and 0.1% of TritonX-100) was used as mobile phase. The Pt-HNMTD and Pd-HNMTD chelates were separated completely within 2 min. The detection limits (S/N = 3) for palladium and platinum were 1.2 ng L-1 and 1.4 ng L-1, respectively. The method was applied with good results to the determination of palladium and platinum in water and urine samples.
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