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Book Review Guidelines for Achieving High Accuracy in Isotope Dilution Mass Spectrometry (IDMS) Edited by Mike Sargent Chris Harrington and Rita Harte.

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willow bark was used as an antipyretic
agent. American readers will certainly
find much useful information in the
book and will be stimulated to join in
the environmental debate. But the
authors message to the public that
comes out clearly from the book is
this: the environmental pollutants and
other dangers generally regarded as the
main risks are comparatively harmless,
and the dangers caused by consuming
certain foods and delicacies are greater
than those from man-made toxins.
Based on a risk assessment procedure,
Table 10 claims to list in order the 30
most important potentially fatal dangers
to humans. Pesticide residues come well
down the list, ranked 28th. This crude
and undifferentiated analysis distorts
and drastically oversimplifies the environmental debate. Following that theme
the author contrasts scientists with
“environmentalists” (also called “environmental advocates”). A curious idiosyncrasy is that instead of referring to
anthropogenic (man-made) substances
and activities, the author describes these
as “anthropologic”, a word that the
referee could not find in any of the
usual dictionaries.
Perhaps the position taken by the
author in this book is intended to
rehabilitate the standing of the chemist
in society. The author believes that the
bad reputation of chemistry in the eyes
of the public is largely caused by misinformation in newspapers and television, which he now hopes to counteract.
The book has a good subject index,
but the choice of literature references is
not balanced. A fundamental weakness
of the book is that it tries to include too
much information, attempting a scope
that is too wide-ranging at the cost of
neglecting depth and accuracy. The
chapter on fats provides some examples
of that. The general statement on page
17 that “lipids are water-insoluble biomolecules ...” is incorrect, since many
emulsifying agents are lipids that are
partly soluble. Also not all lipids are
“biomolecules”, as is shown by the “fat
substitutes” described in the same chapter. By the term “trans fats” the author
presumably means trans fatty acids.
Although cis fatty acids occur less
frequently than the corresponding trans
isomers, they are not “unnatural” as
implied, since they are formed during
1564
the breakdown of trans fatty acids by
metabolization in humans and animals.
The author uncritically cites the alleged
influence of the consumption of trans
fatty acids on the incidence of breast
cancer, whereas it is a matter of scientific controversy, and publications to the
contrary should have been mentioned.
Weaknesses such as these come to light
on careful looking through the book.
The description of the aromatic hydrocarbons present in gasoline as “mild
carcinogens” (p. 166) is an incorrect
generalization. Also the book completely fails to mention the effects of
endocrine disruptors that have recently
been discovered.
In this book the author has tried to
cover in a brief form the whole field of
environmental dangers. It should be
read with a critical attitude, and can
only be recommended with reservations.
Dieter Lenoir
GSF Forschungszentrum
Neuherberg/Mnchen (Germany)
Guidelines for Achieving High
Accuracy in Isotope Dilution Mass
Spectrometry (IDMS)
Edited by Mike Sargent, Chris Harrington and Rita Harte.
Royal Society of
Chemistry, Cambridge 2002. 50
pp., paperback
£ 29.95.– – ISBN
0-85404-418-3
The aim of this little paperback book, as
stated at the beginning, is to describe
procedures in isotope dilution mass
spectrometry (IDMS) that will enable
laboratories to obtain reliable analytical
data for specific applications, without
themselves having to undertake the
considerable work of developing suitable protocols. It is mainly based on the
findings of a sub-committee that forms
part of a Valid Analytical Measurement
(VAM) program set up by the UK
Department of Trade and Industry,
1 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
aimed at defining accurate and reliable
analytical procedures. Although the
book has not achieved its ambitious
aims completely in every detail, it can be
said at once that it will be useful to every
analytical laboratory which, in view of
the increasing importance of validating
analytical data, wishes to begin using the
highly reliable method of IDMS.
The principle of the isotope dilution
method is that one adds to the analytical
sample a precisely known amount (the
“spike”) of the element that is to be
determined, in isotopically enriched
form, or, in the case of molecular
analysis, of an isotopically labeled form
of the compound in question. After
allowing time for equilibration between
the original sample and the spike,
whereby the spike becomes diluted,
one measures the resulting isotope
ratio, usually by mass spectrometry
(hence IDMS). Since its introduction,
IDMS has already proved to be very
successful for some specific applications,
especially for the determination of uranium and the transuranium elements in
nuclear technology, and of radioactive
nuclides in the dating of geological
specimens. Other fields in which the
method has become very important are
the analysis of clinical specimens, some
special types of environmental problems
(e.g., determination of dioxins), and in
connection with the certification of
concentrations of elements in reference
materials. In all these cases the reason
for using IDMS is the necessity to
achieve a high level of accuracy in the
analytical data. Until recently the main
obstacle preventing wider use of the
method in the areas of elemental trace
and element species analysis was the
need for laborious sample preparation,
to enable the measurements to be carried out by thermal ionization mass
spectrometry (TIMS). However, in
recent years the level of interest in
applying IDMS in those areas has risen
sharply because of the enormous growth
in the use of inductively coupled plasma
mass spectrometry (ICP-MS), with the
advantages of easier sample preparation
in most cases, multi-element capability,
and—for the identification of element
species—the ease of on-line coupling to
chromatographic methods.
The book begins by listing and discussing the advantages and disadvanAngew. Chem. Int. Ed. 2003, 42, 1563 – 1565
Angewandte
Chemie
tages of IDMS. The main advantage is
that, subject to certain preconditions, it
can yield accurate and reliable analytical data, so that it is now widely
regarded internationally as a definitive
method. Provided that complete equilibration between the spike and the
sample has occurred, one can be confident that the analytical result is not
affected by any loss of material, as the
only quantity measured is the isotope
ratio, rather than an amount of material
that must be isolated from the analyte.
However, the books discussion of the
advantages and disadvantages contains
some statements that might result in a
misleading evaluation of IDMS. For
example, it is wrongly stated that the
accuracy of an IDMS analysis is determined by the precision with which the
isotope ratio can be measured. Since the
determination of the isotope ratio
requires the measurement of the MS
peaks of two isotopes (or of two different mass numbers in the case of molecular analysis) free from spectroscopic
interferences, the possibility of such
Angew. Chem. Int. Ed. 2003, 42, 1563 – 1565
interferences is a significant source of
error in IDMS analysis. Also the mention of the (supposedly high) cost of the
isotopically enriched spike as a disadvantage is only justified in some circumstances. Apart from a few exceptions,
the IDMS method is still used almost
exclusively for trace analysis. In these
applications the optimal amount of the
spike to be added is of the same order as
the amount of the element present in the
sample. For trace analysis that typically
requires one to use a few micrograms of
the spike or even less. Since 1 mg of an
isotopically enriched material is likely to
cost only between $ 0.001 and $ 1, that is
not of much practical importance for
elemental trace analysis. On the other
hand, for organic molecular analysis or
element species analysis, where one has
to take into account the time needed to
synthesize an isotopically enriched compound in ones own laboratory (because
very few isotopically labeled compounds
are yet commercially available), the
IDMS analysis can be relatively expensive.
www.angewandte.org
The book has a number of defects.
For example, some of the literature
citations mentioned in the text are
missing from the list of “Keynote References”, the diagrams for determining
the optimum quantities of spike to be
added are very badly drawn, and are
only valid for a spike with an arbitrarily
assumed level of isotopic enrichment,
and the book neglects the use of IDMS
for element species analysis, an application that is becoming increasingly
important. But for the reader who is
not too disturbed by these shortcomings,
this little book at least offers a compact
and useful introduction to the fundamentals of IDMS. However, laboratories intending to begin using IDMS
should not regard the book as a substitute for reading some important
review articles and original papers on
the subject.
Klaus G. Heumann
Institut fr Anorganische Chemie
und Analytische Chemie
Universit;t Mainz (Germany)
1 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1565
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