ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Simultaneous quantification of trace gold and platinum in copper alloys recycled from printed circuit boards using SPE coupled with ICP-AES

Avijit Chakraborty, Asami S. Mashio, Nozomi Komura, Fumiya Haruki, Susumu Watanabe, Shafiqur Rahman, Kuo H. Wong, and Hiroshi Hasegawa

Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Japan

E-mail: avijit.chakraborty@cu.ac.bd

Received: 22 February 2026  Accepted: 7 April 2026

Abstract:

Copper (Cu) alloys recycled from printed circuit boards represent an important secondary source of precious metals (PMs), including gold (Au) and platinum (Pt). However, the complex composition of these alloys, particularly the high Cu content relative to PMs, poses significant analytical challenges for the accurate quantification of trace PMs. In this study, a reliable and selective method was developed by coupling solid phase extraction (SPE) with inductively coupled plasma atomic emission spectroscopy (ICP-AES) for the determination of Au and Pt in Cu-rich matrices. The adsorption and elution behavior of a strongly basic (AG1-X8) and a weakly basic (Diaion WA30) anion exchange resin were systematically investigated to optimize the separation of both metals. Both resins exhibited quantitative adsorption of Au and Pt in 0.1 mol L⁻¹ HCl, with negligible Cu uptake. Desorption with 1 mol L⁻¹ thiourea in 0.5 mol L⁻¹ HNO₃ efficiently recovered target PMs from metal-loaded resins, enabling their accurate isolation and quantification. Resin reusability was confirmed over multiple adsorption–desorption cycles following sequential washing with Milli-Q water (MQW), 0.75 mol L⁻¹ NaOH, and MQW. A robust digestion protocol employing aqua regia, HF, H₂SO₄, and H₃PO₄ was established for the dissolution of Cu alloy and oxide samples, and the adsorption performance of the resin in H₂SO₄ medium was evaluated for the first time. The method achieved detection limits of 0.15–0.73 µg g⁻¹ for Au and 0.06–0.30 µg g⁻¹ for Pt, demonstrating its suitability for the quantitative determination of sub-µg g⁻¹ levels of PMs in recycled Cu alloys and other Cu-rich secondary resources.

Keywords: Solid phase extraction; Precious metals; Recycled copper alloys; Printed circuit boards; Anion exchange resins; Thiourea elution.

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-026-04890-7

Chemical Papers 80 (7) 8317–8331 (2026)