Determination of platinum in protein-bound COOP and DBP by inductively coupled plasma optical emission spectrometry and electrothermal atomic absorption spectrometry

The plasma protein binding ability of cis-diammine-{[bis(phosphonatomethyl)amino]acetato(2-)-O-1,N'}platinum(II) (DBP), a tumour-inhibiting platinum phosphonato compound with osteotropic properties, was compared with that of the well established anticancer drug cisplatin (CDDP). The separation of the plasma protein-platinum adducts was performed by a fractionated ultrafiltration experiment. The platinum levels in the protein fraction and the ultrafiltrate of the blood plasma were detected with an echelle-based ICP-OES system with an ultrasonic nebulizer (USN) and by ETAAS with Zeeman-effect background correction. The over-all performance of ETAAS was better than that of ICP-OES. Owing to strong, protein-induced matrix effects in the USN, the ICP-OES measurements resulted in lower platinum levels in the protein fraction of blood In the determination of platinum in the ultrafiltrate, both systems showed good performance. In comparison with CDDP, DBP shows a significant tendency to bind to plasma proteins of lower molecular mass.