The analysis of free-VX from sorbent tubes at low and sub-nanogram levels
Application Note 044
VX is a particularly dangerous nerve agent. It is relatively high-boiling (b.p. 298°C) and vapour-phase concentrations under ambient conditions are extremely low. Limit levels are reviewed regularly.
The current (in 2012) recommended occupational (workplace) limit level (based on an 8-hour exposure) is 0.01 µg/m3, and the current recommended General Population limit level is 0.003 µg/m3. On the basis of a 12-hour sample at 500 ml/min, the masses of VX that would be collected at these limit levels are 3.6 ng and 1.08 ng respectively.
This application note demonstrates measurement of free-VX (i.e. underivatised VX) at the sub-nanogram level using a standard non-passivated ULTRA-UNITY™ automated thermal desorption system, in conjunction with GC–FPD.