Measure multiple gases on site
November 1st 2008 Quantitech has launched a portable FTIR multicomponent workplace gas analyser,
which enables operators to measure multiple components simultaneously
In the past, field-use instruments for the
detection of toxic gases have sacrificed
analytical performance for the sake of
usability. As a result, many portable
instruments have merely provided data
that is indicative and non-specific, whereas
analytical instruments have been difficult
or impossible to operate in the field.
The Gasmet Dx-4030 from Quantitech is
a new analyser providing both fieldusability
and high levels of analytical
performance. It employs FTIR (Fourier
Transform InfraRed spectroscopy) analysis
producing almost instantaneous readings
for multiple compounds across a wide
measurement range that extends to subppm
levels.
FTIR is a technique used to determine
the chemical makeup of a sample. The DX-
4030 scans the mid IR spectrum 10 times
per second and detects the amount of IR
energy absorbed by the gas sample at a 7
wavenumber (cm-1) resolution. The DX-
4030 can measure any gas molecules that
have vibration energies within the IR
spectrum, and as every measurable
compound has a unique fingerprint of
peaks, accurate readings and interference
compensations can be achieved. The DX-
4030 can measure any gas with the
exception of diatomic gases (O2, N2, Cl2
and so on), noble or inert gases, and H2S.
No sample preparation is needed; the
sample gas is drawn into the analyser
module by an internal diaphragm pump
via a wand-type sample probe, which has
a built-in particle filter. The whole system is
battery operated with an operating time of
several hours.
Data collection and display is facilitated
by a PDA (Personal Digital Assistant) user
interface with the 'Calcmet–Lite' software.
The analyser module and the PDA
communicate via wireless Bluetooth
protocol and measurements for each
compound are displayed on the PDA. The
system can also be operated in a wired
configuration using an RS232 cable for
situations where radio silence is required.
Quantitech's Dr Andrew Hobson
provides technical support for the new
analyser – he has already visited a wide
variety of sites around the UK to give
demonstrations and advice on how best to
exploit the benefits of the new technology.
This has included on-site analysis of
workplace and process gases in
applications as diverse as chemical spill
response, homeland security, industrial
hygiene, contaminated land, leak detection
and the measurement of anaesthetic
gases in hospitals.
To configure an application the operator
defines the matrix of gases that are
expected in the workplace and the typical
concentrations. Water and CO2 plus
other gases present in ambient air are
also included in the application library
that is created. A typical application will
include 15 compounds, for more complex
mixtures as many as 25 gases and
vapours can be
programmed. The operator
does not need an expensive
collection of gas standards
to configure the system,
stored calibration reference
spectra contain all the information
needed to set up the analysis
application. A single test gas may
be used to validate the analysis if
necessary.
In the workplace, the
operator can read the
concentration of all
measured components in
real time. This data is stored
as a universally compatible text file in the
PDA so that results can be exported when
the survey is complete. In addition, the
operator can choose to store the IR
spectra from which the analyses are made.
If there is any question about the validity or
accuracy of a particular value, the
complete analysis can be examined and
validated offline. So, if a new material is
sampled unexpectedly during a survey, the
DX-4030 will report that the analysis is
invalid but continue to store the spectra.
Analysis of the stored IR spectra provides
an opportunity to identify the unknown so
that the calibration can be added to the
application. The stored data can then be
re-analysed to calculate correct results for
all measured components.
Commenting on the launch, Quantitech
director Dominic Duggan says "We were
responsible for launching the Miran gas
analysers in the UK market and it is
pleasing to return to the market that we
used to lead. We are very excited about
the DX-4030 because we foresee a great
demand for this advanced technology." More articles from Quantitech Ltd: | 
