The testing was done at the University of Helsinki Laboratory. An HNU model GC311 with a PID (10.2 eV). The goal was to test the HNU Systems GC 311 for the verification of Chemical Warfare (CW) agents.
Materials & Methods
The CW-agents investigated in this work are listed in Table 1, The standard solutions of Model compounds were prepared in Methanol by consecutive dilutions of stock solution containing 100 ug/uL in ethyl acetate. Methanol was chosen as the solvent to eliminate a large solvent peak due to the lack of a split valve in the GC311. Methanol is not ionized by the 10.2 eV lamp.
The GC311 was equipped with a photoionization detector (10.2 eV) . The compounds were separated on a fused silica capillary column (phase NBW 311, 15M x 0.53 mm id x 1.5 um film thickness) . The injection volume varied from 2.5- 5uL. Injector/detector temperature was 200C and the oven temperature was 100 C for sarin, soman, tabun and mustard gas and 150C for Lewisite-3.
Results and Discussion.
Figures 1 & 2 show chromatograms of a standard solutions of sarin, soman, tabun and mustard gas at concentration levels of 100, 50, 4 and 1 ng. The detection limit of sarin, soman, tabun and mustard gasis about 1 ng and for mustard gas is 0.5 ng which is about 10 x better than that of the FID run at the same time. The sensitivity of the Lewisite-3 is 0.2 ng because of the 3 double bonds in that compound.
The portable GC311 has been shown to be a powerful instrument for the detection of CW-agents especially for the direct analysis of air samples. The instrument can also be used for the monitoring of incinerator exhaust gases during the destruction period of CW-agents. The analyzer could be more useful for the analysis of liquid samples if a split injector were available.
The GC311 is no longer in production but a new portable GC is available from PID Analyzers, the Model GC312.
Photo GC311 (no longer in production)
Photo GC312 (replacement for GC311)
The work in this report was done with an HNU GC311 shown above. The replacement instrument described in this report is a GC312 manufactured by:
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