Explaining
the Science behind the Heavy Metal
Test
Dr.
Joachim Leman
Medical Laboratory Expert
–Toxicologist
Germany
Heavy
Metal Test (HMST)
In the eyes of a chemist, this test is composed
of two essential chemical steps. The first one is a
complex forming reaction between metal ions and Dithizone
at the phase border separating aqueous solution and
Testsol-phase; the second one is an extraction of the
performed complex into the organic layer. The two
essential steps as well as the preceding one and the
evaluation procedures are very common processes in
analytical chemistry and form part of many other
determination methods used in clinical
chemistry.
Dithizone
(1,5-Diphenylthiocarbazone) is a current reagent since it
was introduced in trace-analytical chemistry in 1925. It
is excellently suited for trace determination of one- to
three valent ions of several transition metals. The
formed complexes vary in composition and color depending
on pH and dipole strength of the solvent in use. Thus
they can be applied for the discrimination of different
elements and their quantification by
colorimetric.
Testsol is a
proprietary product, which joins the advantages of
ecological harmlessness, lack of toxicity and
inflammability under normal conditions, whereas the
chloromethanes used up to now are highly toxic and
ecologically objectionable.
The comparative colorimetric evaluation is
performed by matching color panels with printed colors
based on the Pantone code defined colors of pure
complexes. In our hands this match was astonishingly
reliable.
We thoroughly
investigated the sensitivity and specificity of the HMST-
system and we can furnish the proof at any time that the
detection of the claimed individual metal species of
toxicological relevance is possible at the lower ppm-
level. Under favorable circumstances we could detect
metal ions even at the ppb –level. Thus one can obtain
important preliminary information for clinical decisions
in the medical cabinet or during a
bed-side-examination.
The high
sensitivity of this test-kit is naturally dependent on
the correct test-execution and prone to failure due to
e.g. omitted pH-adjustments, shortened waiting periods or
wrong consecution of additions.
So you can see
that there is no room for any doubts concerning the
respectability and reliability of the HMST Test-Kit. It
is based on a scientifically approved method and suitable
for clinical purposes so that health insurance companies
are supposed to refund the costs for its
execution.
Yours
sincerely,
Dipl.-Chem.Dr.rer.nat. Joachim
Leman
Further Excerpts from Expert
Evaluations of Heavy Metal
Screening
[ ... ] We
thoroughly investigated the test system with regard to its
sensitivity and its specificity and found consistent
evidence that it is possible to detect individual
toxicologically relevant metals in urine or water specimens
in the range of a few ppm, at times even fractions of one
ppm. This makes it possible to obtain on the spot clinically
important preliminary data [ ... ]
(J. Lemann, Dr. rer.nat., Toxicologist and Medical Expert,
Institute for Toxicology and Medical Laboratory
Diagnostics, Hirschberg
,
Germany
)
[ ... ] This
report is intended to be an independent assessment of the
claims of performance of a novel detection system for some
transition metals. These materials are commonly known as
toxic or heavy metals. [...] it was found that the
system shows remarkable sensitivity for such a simple
procedure [ ... ]
(K.H. Bell, Ph.D., Professor and Head, Department of Chemistry,
The University of Newcastle, NSW, Australia
)
[ ... ] Until
the beginning of the nineteen-seventies this reagent was
in predominant use for the detection of heavy metal
traces in the water supply. It is a certified German
Government Standard procedure for water supply
analyses. [ ... ]
(G. Schwedt, Dr. rer.nat.,
Professor and Director, Institute for Inorganic and Analytical
Chemistry, Technical University of Clausthal,
Germany)

Return from
Heavy Metal Test Science to Human Heavy Metal Toxicity
Testing.
|