Determination of gold and platinum in the presence of blood plasma proteins using inductively coupled plasma mass spectrometry with direct injection nebulization

Abstract

The effects of the blood plasma proteins albumin (67 kDa) and transferrin (80 kDa) on the determination of Au and Pt, respectively, by ICP-MS using direct injection nebulization (DIN) or conventional pneumatic nebulization (PN) have been investigated. Detection limits using DIN were determined to be 0.6 pg (0.03 µg l^–1) and 1.6 pg (0.08 µg l^–1) for ¹⁹⁵Pt and ¹⁹⁷Au in 1.0 µmol dm^–3 solutions of transferrin and albumin, respectively, in 0.1 mol dm^–3 TRIS buffer. Precisions were high, ca. 0.5% over the range 1–100 µg l^–1. Calibrations were obtained with excellent linearity, and there was a wide linear dynamic range of four orders of magnitude with little interference from the protein. The binding of the anti-arthritic compound triethylphosphine gold(I) chloride (Et₃PAuCl) to albumin at various Au:albumin molar ratios was investigated using DIN-ICP-MS. It was concluded that DIN-ICP-MS is an improved method for determination of Au and Pt in the presence of proteins and therefore potentially valuable in pharmacological studies.