VALIDATION OF THE DETERMINATION OF COPPER AND ZINC IN BLOOD-PLASMA AND URINE BY ICP MS WITH CROSS-FLOW AND DIRECT-INJECTION NEBULIZATION

The simultaneous determination of copper and zinc in human plasma and urine by inductively coupled plasma mass spectrometry (ICP MS) is disc ussed. The performances of a cross-flow nebulizer and a direct-injecti on nebulizer (DIN) were compared. Flow-injection-DIN-ICP MS analysis o f clinical samples using 1-2 mu l samples was optimized. Isobaric inte rferences were discussed and were demonstrated to be eliminated for th e Cu-65 and most of the Zn nuclides. The need for standard addition to compensate for signal suppression in the case of some serum samples w as indicated. Results obtained by ICP MS using calibration with aqueou s standard solutions were found to be in good agreement with those obt ained by flame AAS for a batch of real blood plasma and urine samples. The methods developed were validated by analysis of several standard reference materials. (C) 1997 Elsevier Science B.V.