these facilities. While these methods have allowed safe waste processing and closure activities, they are tedious and indirect, generally relying on vapor-phase agent measurements over confined surfaces rather than direct detection of surface contamination. Chapter 3 also develops and describes a half-dozen scenarios involving prospective ACWA secondary waste characterization, process equipment maintenance and changeover activities, and closure agent decontamination challenges, where direct, real-time agent contamination measurements on surfaces or in porous bulk materials might allow more efficient and possibly safer operations if suitable analytical technology is available and affordable.
The last 5 years have produced very rapid development of ambient ionization mass spectrometric techniques capable of real-time surface and bulk material chemical analyses with little or no sample preparation. Two of these technologies, desorption electrospray ionization (DESI), first introduced in 2004, and direct analysis in real time (DART), introduced in 2005, are now commercially available and have widespread applications. Both DESI and DART, as well as a range of variations on each, are reviewed in Chapter 4, which also details their application to the detection and quantification of chemical agent and agent simulant compounds. The utility of various DESI and DART implementations to meet the chemical agent contamination characterization challenges identified in several of the ACWA operational and closure activity scenarios developed in Chapter 3 is addressed in Chapter 4. Chapter 4 also discusses the potential utility of real-time agent vapor concentration gradient measurement methods to locate specific contaminated surfaces. It concludes with a comparison of the strengths and weaknesses in (1) the current Army indirect methods to characterize chemical agent contamination adsorbed on solid surfaces and absorbed by porous materials and (2) direct measurements using ambient ionization techniques. Based on this comparison, the chapter presents findings and recommendations involving specific ambient ionization technology configurations that could guide specification, acquisition, and integration of this technology, if ACWA management determines that the ability to directly characterize the distribution of chemical agent concentrations on and in solid materials and the concentration gradients of airborne chemical agents is sufficiently useful to justify the effort and cost required to implement this type of technology.
Efficient and effective use of any analytical technology must employ statistically robust measurement strategies. This is particularly true when dealing with the characterization of contamination by deadly substances like chemical agents. Chapter 5 briefly examines the published statistical basis of current Army chemical agent contamination characterization methods, presents a detailed analysis of recently published DART measurements of chemical agent concentrations in liquid solutions, and then examines the statistical basis of direct surface agent contamination characterization using various implementations of ambient ionization mass spectrometry techniques.