Fast GC-PFPD system for field analysis of chemical warfare agents

Abstract

A fast gas chromatograph (GC) equipped with a pulsed‐flame photometric detector (PFPD) was designed and built with the intention of facilitating field analysis of the full range of chemical warfare agents (CWA). This GC‐PFPD system was tested with five organophosphorus and organosulfur CWA simulants that cover the volatility range of common CWA. Fast repetitive analysis was demonstrated with a cycle time as short as 30 s, combined with very low detection limits of 20 ng/m3 for organophosphorus CWA simulants and 200 ng/m3 for organosulfur compounds. With a longer analysis time of 80 s, a 3‐ng/m3 detection limit was demonstrated for DMMP. In the GC‐PFPD system, the separation power of each of these techniques is orthogonal and independent; thus, this hyphenated combination is characterized by a very low false‐alarm rate, combined with CWA identification capability at the molecular level. The large improvement in system selectivity is demonstrated in the direct analysis of a low level of triethylphosphate in the headspace of diesel fuel without any interference. The system inlet was heated and the sample path was inert without any metal, enabling fast response time and low detection limits for a low volatility agent such as VX. The same fast GC‐PFPD system could also be quickly and easily switched to a continuous sampling “sniff” mode of operation with 2‐s response time. Alternatively, it could be operated in a novel mode of thermally modulated inlet (TMI) that provided intermediate results between those of GC and “sniff” in terms of the trade‐off of response time and performance. The fast GC‐PFPD system is also characterized by low average hydrogen consumption (about 4 ml/min), small size, and low weight. No attempt was made to complete the system in terms of portable control electronics. The advantages and unique features of this system, as well as the importance of CWA identification at the molecular level, are discussed. © 2000 John Wiley & Sons, Inc. Field Analyt Chem Technol 4: 170–194, 2000

Study of the Effect of Air to Fuel Ratio Parameter on the Organophosphorus – Pesticide Analysis by GC-FPD

“…The plot shows the linearity of the detector with Malathion and Dimethoate with R 2 value higher than 0.997 over the studied concentrations range, which indicate good linearity. Similar results for R 2 (0.999-0.9823) were obtained in a study using GC/PFPD and GC/MS for the determination of trace OPPs, [12][13][14]. Figures 11 and 12 presented the determined linearity of the detector with Malathion and Dimethoate, respectively.…”

Gas Chromatography in Screening of Chemicals Related to the Chemical Weapons Convention

“…(57) The ability to also detect arsenicor nitrogen-containing chemicals makes the PFPD very useful for the screening of CWC chemicals. Frishman and Amiraw (58) used fast GC equipped with a short capillary column (1.5 m) and PFPD for the analysis of air samples. A complete analysis cycle time of 30 s was demonstrated.…”

Conventional analytical methods for chemical warfare agents

“…However, when selective detectors are used in combination with GC, the separation time can be reduced significantly. For example, using a pulsed-flame photometric detector, which is highly selective for phosphorus-and sulfur-containing compounds, detection of 20 ng/m 3 of organophosphorus compounds and 200 ng/m 3 for organosulfur compounds can be accomplished within 30 s [18].…”