Rapid and sensitive determination of leached platinum group elements in organic reaction solution of metal-catalyzed reactions by laser ablation-ICP-MS with spot-drying on paper

Abstract

The evaluation of the leaching of metals is important in the study of metal-catalyzed reactions. However, analytical methods for the determination of trace metals in organic reaction solution require high purity reagents and time-consuming digestion processes. We present a rapid and sensitive method for the determination of platinum group elements (PGEs) in an organic reaction solution using LA-ICP-MS. Novel sample preparation for the dried solution spot and linear scanning ablation method was developed for the total sampling technique. For a 0.1 μl solution sample, the detection limits of PGEs were 0.034 to 1 ng ml⁻¹ and the detection efficiency of sampling of the detector was 1.5 × 10⁻⁵ to 3.3 × 10⁻⁴. The proposed method does not require pre-treatment such as digestion, dilution and addition of internal standards to the sample and can be completed within about 5 minutes including sample preparation. To demonstrate the adaptability to organic reaction solution, the quantitative analysis of Pt leaching in continuous-flow hydrogenation reactions with Pt/C as a fixed bed catalyst was performed by the proposed method and compared with the conventional microwave-assisted acid digestion/ICP-MS and isopropanol dilution/ICP-MS methods. The determined concentration showed good agreement with the concentration determined by the conventional methods. The relative deviations of the measured value by LA-ICP-MS were −4.1% from the value obtained by MW/ICP-MS and −3.6% from the value obtained by IPA-dilution/ICP-MS, confirming the accuracy of the proposed method. This method will be a powerful tool for the evaluation of metal leaching and for the analysis of trace metals in organic reaction solutions.