Near real time detection of hazardous airborne substances
J. Leppert et al., Talanta, 2012, 101: 440–446
In this paper, researchers led by Jan Leppert at the University of Bonn in Germany demonstrate the sensitivity of ALMSCO’s BenchTOF-dx TOF MS by detecting trace-level chemical warfare agents (CWAs) in air.
The exposure limits of many hazardous compounds are subject to downward revision as their biological effects become better understood, but none come close to the limits specified for CWAs, which can be as low as 10 ppt. This application therefore demands highly senstitive instrumentation, with the added requirement for a short cycle time to ensure rapid response to changing concentrations.
To address these challenges, Leppert’s group determined the limits of detection for five CWA simulants using fast GC and BenchTOF-dx, in conjunction with TT24-7, a continuous monitoring TD system from Markes International. Limits of detection for these simulants were estimated to be 20–150 pg, which the authors say is two to three orders of magnitude lower than that for a GC used with a full-scan quadrupole MS. In addition, they were able to detect trace concentrations of real CWAs, including sarin, sulfur mustard in diesel, lewisite under humid conditions, and VX.
The authors point out that BenchTOF-dx produces ‘classical’ EI spectra without skew or bias, making them library-searchable and thus simplifying compound identification. Aiding the analysis in this case was TargetView software from ALMSCO, which was used to separate the chromatographic peaks and identify the target compounds.
Leppert says that “the combination of [thermal desorption] and the TOF MS results in a very sensitive detection system”. In addition, he says that the ability of the GC/TOF MS system to detect a wide range of hazardous substances could allow the application area to be extended further, to cover the detection of toxic industrial chemicals and drugs, or for spot-checking inspections of cargo containers.