H. Vanhoe et al., USE OF INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY FOR THE DETERMINATION OF ULTRA-TRACE ELEMENTS IN HUMAN SERUM, Journal of analytical atomic spectrometry, 9(1), 1994, pp. 23-31
A method for the determination of 11 ultra-trace elements (Li, B, Mo,
Cd, Sn, Sb, Cs, Ba, Hg, Pb and Bi) in human serum by inductively coupl
ed plasma mass spectrometry is described. Sample preparation was kept
to a minimum: serum samples were diluted 5-fold with 0.14 mol l-1 HNO3
and suitable internal standards (Be, In and TI) were added to correct
for matrix effects and for ion signal instability. Special attention
was given to optimization of the electrostatic lens settings and the n
ebulizer gas flow rate. Detection limits between 0.007 ng ml-1 (for Bi
) and 0.5 ng ml-1 (for B) could be obtained, taking into account a 5-f
old dilution of the serum sample, Memory effects, which can be experie
nced with the conventional methodology for sample introduction, leadin
g to positive errors, were reduced to a negligible level by the use of
a short (2 min) clean-out procedure. With the exception of B (1-2 ng
ml-1) and Pb (0.08-0.15 ng ml-1) blank levels were shown to be below 0
.1 ng ml-1. Results are given for a 'second-generation' biological ref
erence material Freeze-Dried Human Serum (University of Ghent) and for
Human Serum SRM 909 from the National Institute of Standards and Tech
nology (for Li, Cd and Pb). Finally, serum samples from healthy indivi
duals were analysed in order to determine typical element concentratio
ns for normal human serum.