Table 1.

Key measurement challenges and impact on the detection of target oxidizers from explosive fuel-oxidizer mixtures, and potential solutions or avenues for improvement.

Key Measurement Challenge	Impact on Oxidizer Detection	Potential Solutions
Trace particulate threat material	Low probability for collection (and detection) Low area relative to target surface area	Large area sampling methods (e.g., swipe sampling) Rapid sampling and collection methods
Low vapor pressure refractory salts	Minimal vapor at room temperature for direct vapor detection Elevated temperatures needed for efficient thermal desorption	Reagent-based chemical conversion to more volatile conjugate acid Dissolution in liquid High temperature thermal desorption
Ionic cluster and adduct formation	Wide ion distribution yielding numerous alarm channels Reduced sensitivity by spreading signal across adducts/clusters	In-source collision induced dissociation manipulating ion distribution Dopant addition for preferential ionization pathways Judicious choice of separation buffer
Interference from fuels and additives	Dark fuels suppress colorimetric detection Ignition from laser excitation of spectroscopic techniques Complex mixtures yield matrix effects (e.g., signal suppression)	Dissolution and physical separation Preferential ionization schemes Judicious choice of separation buffer Orthogonal detection capabilities
Interference from environmental background	False detection from environmentally occurring anions Signal suppression and matrix effects from complex background Background fluorescence	High selectivity techniques Advanced alarm algorithms / adjusted thresholds