accumulation in plants, fish and animals of organo-metallic compounds
resulting from human activities can cause serious ecological and health
problems. However, the toxicity of trace metals may depend greatly upon
the type of molecule in which they occur. A group of European research
institutes has worked together to produce the world's first instrument
that will allow routine analysis of individual molecular species at a
widely affordable cost.
of people in the Japanese village of Minimata died in 1955 after ingesting
an organic form of mercury transported by fish. This tragedy dramatically
highlighted the dangers of toxic organo-metallic molecules. Concerns at
the increasing concentrations of lead entering the food chain, mainly
from vehicle exhaust emissions, have also resulted in the widespread withdrawal
of leaded fuels. But, even today, there is no universally agreed method
of quantifying such pollutants.
European conference held in Bordeaux in the early 1990s brought
together three leading researchers with a keen interest in the subject.
At that time, measurement of the problem compounds was only possible
using costly and complex combinations of techniques. Such work was
being carried out by only a relatively small number of specialists,
and there were no common grounds for reliable comparison of results.
Wolfgang Buscher (Institut
für Chemo- und Biosensorik, Germany), Professor Richard
Lobinski (Laboratoire de Photophysique and Photochimie, France)
and Professor Freddy Adams (University
of Antwerp, Belgium) therefore introduced a proposal to develop
a low-cost, easy-to-use instrument that would allow much broader
investigation of the problem.
million Automated speciation analyser (ASA)
project was launched in October 1996 with approximately 43% funding
from the EC. By the end of its 39-month term, a prototype system
had successfully been demonstrated at international analytical conferences,
and a manufacturer was identified to produce the instrument on a
and versatile system
ASA employs a three-stage procedure to determine metal concentrations
at trace and ultra-trace levels in naturally occurring materials
such as flesh and plant tissue:
1. The samples are chemically treated to convert the target molecules
into a volatile form, which can be extracted by boiling off and
collecting in a receiver cooled to -100°C - a so-called 'purge
and trap' process.
2. The trapped extract is purified by gas chromatography (GC),
whereby it is diffused along with a carrier gas through a column
containing a liquid stationary phase. Because of their differential
solubilities and volatilities, individual components emerge from
the column at different times, and can thus be isolated.
3. The organo-metallic compound is subjected to elemental analysis
in a specially designed optical emission spectrometer (OES) module.
Heating to a very high temperature in a miniature microwave-induced
helium plasma causes the constituent elements of the compound
to emit their characteristic spectra. The wavelength of interest
is isolated by means of a selective filter, and the concentration
of metal present measured with an element-selective detector.
and trap separation is completed in around three minutes, while
the use of a bundle of more than 900 capillary columns reduces the
GC stage by five to ten times compared with conventional systems.
Consequently, complete analyses are accomplished in as little as
ten minutes, making this an extremely practical tool for routine
date, the ASA has been equipped to determine mercury, tin and lead.
Switching from one element to another is extremely simple, involving
only the replacement of the interchangeable filter. Excellent results
have been achieved in the analysis of standard reference materials
such as fish and lobster tissue. Further extensions of the elemental
range are planned for the future.
system is compact enough to fit into a modest workspace, while employing
filters rather than complex OES optics was a key factor in reducing
the overall cost of the instrument. Moreover, the fact that it can
also be used in a normal GC mode with, for example, carbon selective
detection, will add further to its appeal.
completion of the project, German analytical equipment supplier
the rights to manufacture and market the analyser. It is hoped that
a commercial version will be ready for launch at the Pittcon
2001 exhibition in New Orleans, USA.
co-ordinator Wolfgang Buscher notes that initial interest will probably
be confined to the 2-300 researchers currently working on speciation
analysis around the world. However, the availability of a rapid,
simple and inexpensive analyser could trigger the enactment of much-needed
new legislation to safeguard health and improve environmental protection.
In that case, many small and medium-sized laboratories in Europe
will be able to profit from the provision of a valuable public service.
number of EU-funded research projects under the Measurements
and testing generic activity of the Growth Programme focus
on measures to increase consumer protection, health and safety,
and to protect the environment.
Project: ASA - Automated
speciation analyser (SMT 4962044)