Page 147 - Inorganic Mass Spectrometry - Fundamentals and Applications

Inductively Coupled Plas~a Mass S~ectro~et~ 137

~ateria~s Used in the Nuclear Industry
for
Although ICP-MS has been used analysis of nuclear materials, often the entire
instrument must be in an enclosed “hot” enclosure [350]. Sample preparation
equipment, inlets to sample introduction systems, vacuum pump exhaust, and
instrument ventilation must be properly isolated. Many of the materials used in the
nuclear industry must be of very high purity, so the low detection limits provided
by ICP-MS are essential. The fission products and actinide elements have been
measured by using isotope dilution ICP-MS [35 l]. Because isotope ratios are not
predictable, isobaric and molecular oxide ion spectral overlaps cannot be cor-
rected mathematically, so chemical separation is required.

Plastics
Metal doped polymers or plastics that might come in contact with food or drinks
have been analyzed by ICP-MS. Plastics may be contaminated with elements used
in the production process including catalysts. Plastic food wraps have been
analyzed after microwave acid digestion [352,353]. Results were in good agree-
ment with those of neutron activation analysis. Laser ablation of plastics and
polymers [S 1,352,3541 is particularly convenient for semiquantitative analysis to
eliminate the need for dissolution or to examine the homogeneity of inorganic
elements within the materials [352]. The effect of the polymer composition and
laser wavelength on laser ablation sampling efficiency has been investigated [63],
again illustrating the potential difficulties in obtaining quantitative analysis with-
out matrix-matched standards.

Catalysts
ICP-MS is useful for analysis of catalysts from two perspectives: The composition
of the catalysts must be carefully controlled, particularly because the active
elements are often expensive. The catalysts are often finely distributed in a sub-
strate material so their concentration in the bulk material may be quite low.
Second, catalysts, particularly those used in automotive catalytic converters, can
be a significant source of platinum group elements in the environment. Re and Pt
[ 1931. Procedures for the analysis of
have been measured in catalysts by ICP-MS
used catalytic converter materials by ICP-MS have been reported [355]. Accurate
meas~ements are essential for many of these applications so isotope dilution-
based concentration calibration is commonly used.

~~lications in the em icon duct or Industry
High-purity acids, silicon, and other materials are essential for acceptable yields in
the production of semiconductor devices. Cont~nation becomes a more and