Solid Phase Extraction and Spectrophotometric Determination of Palladium with 1-(2-benzothiazolylazo)-2-hydroxy-3-naphthoic Acid

Abstract

A selective, sensitive, and fast procedure to determine palladium depended on the sensitive reaction of palladium(II) with 1-(2-benzothiazolylazo)-2-hydroxy-3-naphthoic acid (BTAHN) coupled with solid phase extraction (CPE) of the BTAHN - Pd(II) chelate with a reversed phase polymer-based C18 cartridge was developed. In 5.0 M hydrochloric acid solution and cetyl trimethyl ammonium bromide (CTAB) medium, BTAHN reacts with palladium(II) to form a deep violet complex with a mole ratio 2:1 {BTAHN to Pd(II)}. The complex was enriched by CPE with a reversed phase polymer-based C18 cartridge. An enrichment factor of 500 was achieved by elution of the complex form the cartridge with least volume of isopentyl alcohol. Beer’s law was obeyed in the concentration range of 0.02 - 0.85 μg mL^–1. The molar absorptivity of the complex was 2.61 × 10⁵ L mol^–1 cm^–1 at 669 nm. The detection and quantification limits were calculated and found to be 6.3 and 19.65 ng in the original samples, respectively. For 0.4 μg mL^–1 level, the relative standard deviation for eleven replicate samples was 1.06%. This procedure was successfully applied to determine palladium in environmental samples with good results.

Key words:

• Solid phase extraction
• Palladium determination
• Thiazolylazo dyes
• Spectrophotometry
• Environmental analysis