Determination of Rh, Pd and Pt in urine samples using a pre-concentration sequential injection analysis system coupled to a quadrupole-inductively coupled plasma-mass spectrometer.

ABSTRACT

The proposed flow system was developed in order to minimize the drawbacks related to the PGEs determination by quadrupole-inductively coupled plasma-mass spectrometry (Q-ICP-MS). It was intended not only to lower the limits of detection (LODs) but also to eliminate the interferences originating from some atomic and molecular ions produced in the argon plasma. This was accomplished by means of an on-line sample clean-up/pre-concentration step, using a chelating resin (Metalfixtrade mark Chelaminetrade mark) in which Rh, Pd and Pt were preferably retained when compared with the interfering species. The results obtained by using the developed flow system in the analysis of urine samples are presented. With a sampling rate of 9 samples h(-1) (i.e., 27 determinations) and a sample consumption of ca. 10 mL, the developed flow system allowed linear calibration plots up to 100 ngL(-1) with detection limits of 1.2 ngL(-1) (Rh), 0.4 ngL(-1) (Pd) and 0.9 ngL(-1) (Pt). Repeatability studies showed good precision (R.S.D.%, n=5) 3.7% (Rh); 2.6% (Pd) and 2.4% (Pt), for 10 ngL(-1); 2.4% (Rh); 1.4% (Pd) and 1.9% (Pt), for 50 ngL(-1); and 1.3% (Rh); 0.58% (Pd) and 0.62% (Pt), for 100 ngL(-1). By spiking human urine samples, recovery tests were performed, and the values obtained ranged between 89% and 105% (Rh); 90% and 104% (Pd); and 93% and 105% (Pt).