EFFICIENCY AND EVALUATION - Total-Reflection X-Ray Fluorescence Analysis and Related Methods - page 403

Figure6.7. Element concentrations found in NIST 1570“Spinach”by ICP-MS (left oblique lines),
TXRF (mottled grey), and INAA (right oblique lines) in comparison to the certified values (solid
black). The bars represent mean values ± standard deviations at n = 6 determinations. Elements
with mass fractions (a) above 10 μ g/g and (b) below 100 μ g/g. Figure from Ref. [87], reproduced with
permission. Copyright1994, Royal Society of Chemistry.
most suitable method. Some characteristics, advantages, and disadvantages
that are of help in such an evaluation are listed in Table 6.4.
As demonstrated by Lieser etal . [90], TXRF can have distinct advantages
over INAA if extremely small volumes (10 μ l) are to be analyzed on traces. On
the other hand, INAA is a nondestructive technique in principle. It is suited for
direct analysis of solids without any sample preparation. In most reactors,
however, it is forbidden to irradiate solutions as a safety precaution but only on
principle; it is actually possible to irradiate solutions.