Flow Injection Analysis Spectrophotometric Determination of Palladium

Abstract

A simple and specific method for flow injection analysis (FIA) spectrophotometric determination of Pd is described. The method is based on color reaction of Pd(II) with organic reagent, i.e., N‐phenylbenzimidoylthiourea (PBITU) over acidity range, 0.2–2.0 M HCl in the 10% (v/v) ethanolic solution. The value of apparent molar absorptivity of the yellow colored complex in the term of Pd is 1.20 × 10⁴ L mol⁻¹ cm⁻¹ at λ_max 345 nm. The detection limit (causing more absorbance than 3s) of the method is 80 ng mL⁻¹ of Pd. The optimum working range was 0.25–10.0 µg mL⁻¹ of Pd with slope, intercept, and correlation coefficient of 0.059, 0.006, and +0.99, respectively. The RSD of the method was ±1.1% for six replicate measurements at level of 2.0 µg mL⁻¹ of Pd. The sample throughput of the method is 120 samples hr⁻¹. The composition of the complex is discussed. The method is specific for the determination of Pd as none of the tested ions interfered. The method has been applied for the determination of Pd in the catalytic materials.

Keywords:

• Palladium
• N‐Phenylbenzimidoylthiourea
• Flow injection analysis
• Spectrophotometry
• Catalyst

Acknowledgments

We are thankful to the Volkswagen Foundation, Hannover, and the Alexander von Humboldt Foundation, Bonn, Germany for the financial support. Our sincere thanks are extended to Dr. N. Jakubowski, ISAS, Dortmund, Germany for reading the manuscript to improve the presentation.