2. ENVIRONMENTAL ChEMISTRy & TEChNOLOGy 2.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Environmental Chemistry & Technology
L03 uSAGE OF GAS ChROMATOGRAPhy
AND IMS DETECTION FOR EVALuATION
OF POLyMER bARRIER MATERIAL
PROPERTIES
JAnA DVOřáKOVáa and IVAn MAŠEKb aVOP-026 Šternberk, s.p., division VTÚO Brno, Veslařská
230, 637 00 Brno, Czech Republic,
bFaculty of Chemistry, VUT, Purkyňova 118, 612 00 Brno,
Czech Republic,
dvorakova.j@vtuo.cz
Introduction
The protective properties are the most important parameters
for selection of well-suited materials for construction
of individual protective equipment (IPE). These properties
determine ability of a given IPE against the highly toxic
agents and industrial harmful substances under short time
and/or long time contamination in the gaseous and liquid
phases.
The most frequently used protective materials for IPE
are polymer barrier materials. Their numerous advantages
such as easy availability, possibility of mass production,
relative low cost as well as the broad range of manufactured
qualities determine their use for different protective purposes.
Single-layer or laminated polymers and textile with polymeric
or elastomeric layer are used as barrier materials. It is
possible to use metallic film, PET sheet with layer of SiOx
(e.g. material CERAMIX from company ALCAn) or other
nanolayers, adsorption textile (e.g. SARATOGA with spherical
sorbent or Charcoal Cloth made from activated carbon
fibres) eventually special membranes (e.g. nAFIOn, GORE-
TEX, POROTEX, PURTEX etc.) with specific diffusion properties
for toxic agents.
Resistance of polymer barrier materials against harmful
substances is defined as parameter called breakthrough
time (BT) 1,2,3,4 . Breakthrough time is the most widespread
way of barrier materials evaluation in term of constructional
usage of materials, their manufacture and conditions of their
selection.
Experimental
The procedures for evaluation of protective properties
are elaborated in accordance with the Czech Technical Standard
ČSn ISO En 6529 (October 2001) which results from
American Standard ASTM F 739-99a (August 1999)5,6. The
above-mentioned standard describes experimental methods
used for testing of barrier materials resistance against permeation
of liquid and gaseous substances and, among other
things (e.g. conditions of measurement for closed-loop or
open-loop, continual and discontinual measurement, preparation
of samples etc.) recommends suitable analytical techniques
for evaluation of permeation toxic vapors. The gas
chromatography (GC) is one of these techniques which is
commonly used for detection and identification of chemical
warfare agents (CWA) as well as ion mobility spectrome-
s293
try (IMS)7,8,9,10. The 2, 2’-dichlorodiethylsulfide (sulphur
mustard, HD) was used for measurement of permeation as
testing chemical. The double-sided butyl rubber polyamide
fabric was used as the used tested material.
P e r m e a t i o n M e t h o d
The following methods were selected for evaluation of
barrier properties of polymer materials11,12,14,15. The principle
of these methods is illustrated by visual demonstration
on Fig. 1. where the scheme of alternative permeation cell
that is used for measurement at aerodynamics conditions.
The alternative permeation cell respects requirements of
standard ČSn En ISO 6529. This cell is made from stainless
steel. The clamping system is solved by the one central
withdrawal nut (see scheme on Fig. 1.) that makes possible
not only quick clamping and exchange of tested materials but
also total obturation of samples. The tested material separates
the alternative cell into two parts. Upside of cell contains
testing chemical (here sulphur mustard) and on the other side
the permeating gas or vapor is swept away into the carrier gas
leading to detector. The carrier gas and agent vapors mixture
is then analyzed by suitable detection techniques.
Fig. 1. Scheme of alternative permeation cell used for measurement
at aerodynamics conditions
C o m p o s i t i o n o f E x p e r i m e n t a l
S y s t e m
The experimental system for permeation measurement
of toxic agents was designed in accordance with the standard
ČSn En ISO 6529. The clean air comes through drying
column (the clean air is represented by blue arrows) washes
lower part of tested material. The air stream carry away permeating
vapors of testing chemical to the given detector (the
air containing vapors of testing chemical is represents by red
arrow). This system was modified according to the used kind
of detection (see scheme on Fig. 2.).
GC and IMS detector GID-3 were used for analysis of
permeating sulfur mustard vapors. The GC equipped with
FID detector, Agilent 6890, was used for separation of gases
and vapors between mobile and stationary phase. The components
are separated on the basis of holding ability of the
stationary phase into the chromatographic column. This analytical
method enables evaluation of taken samples using