Our Approach The detection of a threat compound relies on an understanding of its physical and chemical characteristics and is impacted by collection tool selection. Our approach begins with studying the available literature about the compound and gaining an understanding of the specific objectives of the project (e.g., determining the presence/absence of the compound, quantitation of its abundance, validation with a low false-positive rate, etc.). Our chemical threat detection expertise lends itself to both method development and validation of existing methods.
If the objective of the project is to develop a chemical threat detection technique, laboratory experiments can be designed to test the collection, preparation, and analytical efficiencies of the target compounds separately in order to determine the overall ability to detect a compound. Some or all of the following parameters are addressed through optimization, evaluation, and validation studies: detection limit, calibration and dynamic range, accuracy and precision, false-positive and false-negative rates, selectivity, reproducibility, ruggedness, robustness, and instrument-to-instrument variability. Detailed Standard Operating Procedures (SOPs) are then developed and transferred to the Client. We have extensive experience developing sample collection systems (see Collection Systems), preparation, and analytical methodologies for a wide variety of sample matrices (e.g., air, swabs, biological, novel collection matrices), target compounds (e.g., organophosphorous compounds, inorganic and organic explosives), and analytical techniques (e.g., fourier transform infrared spectroscopy (FTIR), gas chromotography-mass spectrometry (GC-MS), liquid chromotography-multi-stage mass spectrometry (LC-MSn)).
Our corporate expertise in analytical chemistry, chemical, biological, radiological, nuclear, and explosives (CBRNE) threat materials, quality assurance, statistics, and environmental sampling/analysis allows us to support the validation of deployable chemical sensors. Some of the sensors we have tested in the past include those designed to monitor for and identify chemical agents, toxic industrial chemicals (TICs), or explosive-related materials and include sensors designed to work inside buildings and/or out in the field. Our approach involves first conducting laboratory-scale experiments and then field-scale demonstrations (see CBRNE Field Testing). All testing involves development of a detailed experimental design with a sufficient number of replicates that will produce credible and defensible technical results that can be used to determine sensor effectiveness and assess the sensor's susceptibility to common chemical interferences.
The Signature Science Chemistry Group is staffed by scientists who specialize in organic, analytical, nuclear, polymer, inorganic, and environmental chemistry. Our chemists' experience includes:
Preparation and chemical synthesis of a wide range of compounds including chemical agent precursors, non-CWC chemical agents, explosives, natural products, and commodities from the milligram to plant-scale
Expertise in advanced mass spectrometry and ambient ionization techniques
Extensive experience in radiochemistry, nuclear forensics, with field-portable and laboratory bench-top analytical instrumentation used for nuclear signature detection
Synthesis of a wide variety of polymers from conventional to functionalized polymers
Working with Schlenk line apparatus and hazardous explosive materials
Characterization of samples using molecular spectroscopy techniques including ultraviolet-visible spectrophotometry (UV-VIS), fluorescence, and fourier transform infrared spectroscopy (FT-IR)
Extensive experience developing sample collection, preparation, and analytical methods for a wide range of compounds, including traditional environmental contaminants, organophosphorous compounds, and inorganic and organic explosives signatures
We also employ experts in all other relevant technical disciplines including quality assurance and statistical science to ensure that all experimental test plans will generate defensible data sets (see Quality Assurance Support Services and/or Applied Statistics).
Specialized Equipment/Facilities In our Austin-based Chemical Laboratory, we maintain a variety of sample preparation equipment and analytical instrumentation capable of analyzing most types of samples. Gas chromatographs (GCs), high performance liquid chromatographs (HPLCs), and ultra-high pressure liquid chromatographs (UPLCs) are coupled to a variety of mass spectrometers (including single and triple quadrupoles, linear quadrupole ion traps, and high resolution OrbitrapsTM). Several ionization techniques are available to complement our mass spectrometry instruments, including ambient ionization techniques such as desorption electrospray ionization (DESI), desorption atmospheric chemical ionization (DAPCI), and direct analysis in real-time (DART), in addition to the traditional ionization methods (electron ionization (EI), chemical ionization (CI), electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI)). To complete our analytical suite, the following spectroscopy techniques are available: ultraviolet-visible-near infrared spectrophotometry (UV-VIS-NIR), FT-IR (transmittance and attenuated total reflection (ATR)), fluorimetry, and Raman.
Sample collection method development
Sample preparation method development
Analytical method development
Third-party methods validation
Chemical sensor validation
Design and construction of sample collection devices
Design and execution of field tests
Current and Past Experience Customer Listing Signature Science has recent and ongoing experience working with the Department of Homeland Security (DHS) and related agencies.