Fiber-Optic Raman Detection of Trace Levels of Phosphonate Vapors Chemisorbed onto an Alumina Substrate

Detection of ppm(v) levels of the nerve agent simulants dimethyl methylphosphonate (DMMP) and diisopropyl methylphosphonate (DIMP) by chemisorption to an alumina surface followed by fiberoptic Raman spectroscopic determination is described. Real-time measurements of the increase in the Raman line intensities with respect to time for DMMP and DIMP chemisorption to alumina are presented. A detection limit at the 95% confidence interval of 6 ppm(v) is calculated for DMMP vapors at a vapor flow rate of 100 mL/min. Factors which limit lower detection limits are identified and possible solutions presented.