INTERFERENCE EFFECTS AND THEIR CONTROL IN ICP-MS ANALYSIS OF SERUM AND SALINE SOLUTIONS

Advances in analytical technology have led to the development of a var iety of very sensitive techniques for determination of very low levels of trace elements in biological and/or environmental matrices. Howeve r, the improvement in equipment and data handling has not been accompa nied, in general, by an equivalent attention to the quality of results . In this framework, inductively coupled plasma-mass spectrometry offe rs extremely high detection power for the determination of a wide rang e of elements. The analysis of samples with a complex matrix is nevert heless a very challenging task. The determination of trace elements in solutions containing high salt concentrations, e.g., human serum (9 g /liter NaCl) and saline solution with dissolved solid (5 g/liter NaCl) was studied. The use of reference materials and internal standardizat ion allows the determination by ICP-MS of Br, Ca, Mg, Rb, Sr, and Zn i n serum to be optimized. The signal suppression in the presence of NaC l depends on the ionization potential and mass of the element consider ed. Cluster analysis is applied to a matrix of data of signal suppress ion of 25 elements under different conditions. Four groups of elements with the same behavior were identified and for each group a suitable internal standard was chosen. The use of three internal standards inst ead of a single one improves significantly the experimental accuracy a nd precision in the analysis of saline solutions. (C) 1995 Academic Pr ess, Inc.