Alcohols Can Now Be Analyzed by a Direct Analysis in Real-Time Method, Applications for Chemical Warfare Agent Synthesis

Authors: J. Michael Nilles, Theresa Connell, H. Dupont Durst, James A. Laramée
American Laboratory 2009, Mar, 01, 41, 24-27

 

The cardinal principle for an operation involving chemical agents is to limit the potential exposure to a minimum number of personnel, for a minimum period of time, to a minimum amount of the chemical agent consistent with safe and efficient operations.1 This requires that the synthetic schemes be rapid and free from unnecessary by-products that would require otherwise further sample handling. Thus, acid/base chemistries with alcohols as intermediates are often used to synthesize phosphonofluoridates, phosphoramidocyanidate, and phosphonothioates.

Dovetailing into the cardinal principle is the need for a rapid chemical analysis method that can accurately confirm the identity and purity of the starting materials, intermediates, and final product(s). In order to accomplish these objectives, the U.S. Army’s Edgewood Chemical Biological Center (ECBC) has been using the Direct Analysis in Real Time (DART®™) method (JEOL USA, Inc., Peabody, MA) since 2002.2 Since that time, a flurry of other open-air methods based on the use of metastable species has been seen.

During the course of a large synthesis project comprising many organophosphorus compounds and their isotopically labeled analogs, it was observed that the DART® datum for labeled alcohol intermediates neither corroborated the nuclear magnetic resonance (NMR) datum nor the GC-MS datum. Yet the data from these three analytical methods were in agreement when the final chemical agent product was analyzed. An investigation was initiated in order to discover the cause of this discrepancy, and a procedure was developed that allowed alcohols and organophosphorus intermediates to be analyzed by DART®.