Solid sampling-graphite furnace atomic absorption spectrometry for palladium determination at trace and ultratrace levels

Abstract

In this work, the possibilities of solid sampling-graphite furnace atomic absorption spectrometry for the direct determination of palladium in solid samples of different origin (a polymer, a pharmaceutical drug and a used auto catalyst reference material), and showing substantial differences in their palladium content (from approximately 2 ng g⁻¹ to 326 µg g⁻¹), have been evaluated. The influences of different factors on the results, such as (i) the temperature program, (ii) the use of chemical modifiers, (iii) appropriate wavelength and argon flow selection (depending on the analyte content) and (iv) the sample mass, have been investigated. The method finally proposed shows interesting features for the determination of palladium in solid samples: the advantage of using aqueous standard solutions for calibration, a high sample throughput (15 min per sample), the fact that no hazardous reagents have to be used, the low detection limit (0.4 ng g⁻¹ for enalapril maleate), sufficient precision (RSD values are between 3 and 15%, depending on the characteristics of the sample) and a reduced risk of analyte losses and contamination. Therefore, it is an attractive alternative to the time-consuming pre-concentration approaches currently in use for palladium determination at low levels.