on the quality of ambient air is a field of advantage of ... Benzene, Toluene, and Xylene are substances ... a mean flux of 10_2photons/cm2s ... maximum permitted exposure level of pollution at the place of work [MAK]). ... air. (water < 100 ppm) ... ppmv. 0,01. 0.02. 0,03. Drift time. /s. Figure 3: Ion mobility spectra of different ...
N95- 33269
/ © '7?I n c. Determination Ion
J.W.
¢
of Benzene,
Mobility
Leonhardt
Toluene,
Spectrometer
_, H.
z Institut
Bensch
far
and
Device
Xylene
using
j, D. Berge),
Umwelttechnolgien,
ftir
Spektrochemie
und
Dortmund,
means
of an
Photoionization
M. Nolting
2 AUERGESELLSCHAFT/MSA, 3Institut
by
2, J.I.Baumbach
Berlin,
Germany
Berlin,
Germany
angewandte
3
Spektroskopie,
Germany
ABSTRACT
The continuous ion mobility because which
monitoring
of changes
spectrometry.
Benzene,
Toluene,
of their toxicity.
We present
uses photo-ionisation
tubes
this drift tube has a length tube of about for ionisation
180 V/cm a mean
on the quality
and Xylene
an optimised
to produce
of ambient
air is a field of advantage
are substances
drift tube for
ion mobility
the ions to be analysed.
of 45 mm, an electric
field strength
and a shutter-opening-time
established
was established
interest
spectrometers,
The actual
of 400 Fts. With
flux of 10 _2 photons/cm2s
of special
of
version
within
of
the drift
the hydrogen
tube
used
for the experiments
described. We discuss gasoline
the results
SUPER.
in co-operation
The detection
tween
of gasoline
hand-held
KEY
and others
SUPER
the instrument
lytical
takes
by a data evaluation Xylene
device in some
on Benzene, obtained
of 10 ppbv
procedure
are rather
in this case.
produced industrial
Normally,
spectrometer
charge
spectra
and sensitivity
of different
just now is to be tested laboratories
from Ben-
in mixtures found
is be-
concentrations
and the detection
of the system
used developed
transfer
determination
for the resolution
and scientific
in normal
for this case. The interferences
The ion mobility
as an example
Resolution
and Xylene
the simultaneous
developed
weak.
Toluene,
with the ion mobility
place. Nevertheless
are attached
developed.
portable
problems
limits
are in the range
zene ions to Toluene possible
of investigations
limit of
are well demonstrated.
for special
environmental
A ana-
in Germany.
WORDS
Benzene,
gas analysis,
gasoline,
ion mobility
spectrometry,
Toluene,
UV-ionisation,
Xylene
INTRODUCTION
Ion mobility spectrometryis a very sensitivemethodthatcanbeappliedto monitoringof air pollutantsatsub-partsper million concentrations in ambientair andatambientpressure.An applicationtool is the continuosdeterminationof cancerBenzenein air at work placesand environmentalprotection.Theadditionof aromaticsto petrolliesin thepercentrange.The dangerousrisk follow immediately.Thus,a selective, able to detect maximum
the substances
permitted
Benzene,
exposure
the instrument
lene with MAK
In this work,
values
EXPERIMENTAL
in the range
of pollution
be able to detect
400 times
we present
control
level
must
higher
an UV-lamp
in such an environment
The ion
under
Benzene
measurements
out using supported
matic
diagram
rangement
a prototype drift tube.
is given
of the geometrical marised
ion mobility
in Table
UV-lamp
Toluene,
in Figure
1. Details
tion, and standard
power
to establish
are sum-
Benzene
circuit
gas flow
electric water
air
50 ml/min duplex-shutter
open time
500 las 5 109 V/A H 2 - lamp,
flux
MgF-window
1012 photons/cm2s
diameter
30 mm
drift path
were
(25°C)
500 ml/min
mean
a
45 mm
field strength
170 - 230 V/cm
content