Facilities and Equipment
The energetic materials group has 15,000 sq. ft. of lab, office and conference space in the 18 month-old Beaupre building on URI campus. In addition, thirteen miles from campus on 2200 acres of wildness is our explosive range. The site has two outdoor and one indoor magazines; a 2200 ft2 firing chamber; 200 ft2 cookoff chamber; chemical and tool storage, and a 30 lb TNT equivalence rating. We maintain ATF licenses to store and manufacture, DOT shipping exemptions (25 g solid and liquid) and DEA schedule 1 and 2 licenses. Our firing site manager is also a member of the Rhode Island state bomb squad.
Gas/Liquid Chromatography and Mass Spectrometric Techniques
With technology moving forward and the advent of new instrumentation and techniques, mass spectrometry is becoming a "work horse" of modern age detection and identification of all types of molecules. Unlike in the past when most of the separation of small molecules was primarily done using gas chromatograph (GC) coupled to various commonly used detectors, including mass spectrometers, today most of detection and separation is performed using liquid chromatograph (LC) coupled to mass spectrometer, UV, fluorescence and other types of detectors. The advantage of using LC technique is the ability to analyze more polar and thermally labile compounds without additional workup. Most of energetic materials would, as a result, automatically benefit by transitioning from gas to liquid chromatography for their detection and quantification. However, if the headspace is of concern, or lower and more sensitive detection limits are in order, then gas chromatography is still a very relevant technique for these types of applications. Our lab currently employs both chromatography methods to get overall unbiased results for small molecules elucidation, detection and quantification. The power of mass spectrometry adds additional level of certainty by providing the mass of the compounds that we are trying to identify, and provides accurate mass measurements of up to 5 decimal points and lower than 2 ppm mass shifts in the case of Orbitrap™.
Thermo LTQ Orbitrap XL ion Trap-Orbitrap™ Mass Spectrometer. This instrument is capable of performing a wide range of application from large molecules discovery (proteomics, metabolomics, etc.) to small molecules elucidation (forensic applications). Having linear ion trap instrument in tandem with Orbitrap™ provides enhanced flexibility of fragmentation experiments for advanced applications in molecule research. HCD collision cell, provides the capability of acquiring spectra similar to triple-quadrupole mass spectrometry techniques. Orbitrap’s mass accuracy lowers false positive rates, high resolution leads to high confidence results. Parallel acquisition mode streamlines productivity and provides comprehensive structural information. This instrument provides high MS and MS/MS sensitivities, wide dynamic range and fast cycle times."
Thermo Exactive™ Orbitrap Mass Spectrometer. Main objective of this instrument is to screen, identify and quantify compounds in complex samples rapidly and with high confidence. This small scale bench top instrument provides high resolution, accurate mass data and rapid full scan capabilities to increase throughput. With resolving power of up to 100,000 FWHM and better than 1 ppm accuracy, it is an ideal instrument for wide range of forensic, clinical and other type of research applications. Its easy-to-use approach gained it a wide spread use in environmental, food safety, clinical, forensics and academic laboratories.
Thermo Quantiva™ Triple Quadrupole Mass Spectrometer. This instrument is capable in providing very low limits of detection and quantification for selected compounds. The selected-reaction monitoring (SRM) technique can never be easier with superb sensitivity, speed and wide dynamic range. Active ion management (AIM™) technology allows for lower detection limits via electrodynamic ion funnel, ion beam guide and neutral blocker. Ultra-fast scan rates, allow 500 SRM/s and up to 30,000 defined SRM for our most complex applications. Very easy setup and intuitive software allows for “click-and-play” application for not so familiar staff.
Agilent 6890 Gas Chromatograph (GC x 4) and 5973 MSD (x2). This instrument is designed with dual split/splitless injector port and suitable for wide variety of applications, including: hydrocarbon processing, food safety, pesticide determination, chemical, biochemical, forensic applications and others. It is known to be robust and delivers unprecedented levels of performance, convenience, and ease of applications. Supported sample introduction techniques are direct headspace and solvent-based injections, but can be retrofitted for solid-phase micro-extraction or on-column injections. The power of mass spectrometry offers reliable library spectral match to identify your compounds of interest. Other detectors that are widely used for energetic materials detection are FID and ECD, both being available in our lab.
Thermo Trace Ultra™ GC with ISQ™ 7000 MS is another system in our lab that provides extra versatility in our routine applications. This instrument is equipped with head space autosampler and retrofitted for SPME injection. Low detection limits and a unique ion path for neutrals eliminations, provides us with robust methods for explosives vapor detection. Easy of use software enables routine detection of newly synthesized energetic materials and comparison to tabulated database on regular bases.
Thermo Flash 2000 Elemental Analyzer Coupled with Delta V™ Isotope Ratio Mass Spectrometer. This fully automated elemental analyzer allows us to examine isotope ratios of C, N, S, O and H, which are the most common building blocks of explosive materials, as well as other organic compounds. This instrument provides us with ability to discover the source, and predict mechanistic routes of the final product subjected to specific synthetic pathways. Two modes of operations (Combustion and High Temperature conversion) allows simultaneous separation of both N2 and CO2 or H2 and CO, depending on our needs of application. Embedded TCD permits stand-alone determination of elemental weight percentages, enabling structural confirmation for other analytical techniques.
Teledyne ISCO CombiFlash® Rf 150. Our purification and fractionation system becomes very important and essential during complex synthetic work. When pure standards are required, we are heavily relying on this system to provide needed results. The system operates at up to 150 psi for separation needs, and connected to the mass spectrometer that is equipped with either ESI or APCI source based on the mode of operations. Certain group of compounds only ionize under ESI conditions and would not produce a signal in APCI mode, and vice versa; having both sources minimizes that chance that we will miss compounds of interest. In the case if compounds do not ionize at all, we have orthogonal UV detector to help us alleviate that problem.
Other Chromatography Related Equipment:
A large part of energetic materials research is the thermal behavior of these compounds. For a long time, this has been the foundation of our lab’s energetic materials research. Differential scanning calorimetry (DSC) is an integral instrument in the laboratory; we can screen on the small scale for adverse interactions between materials, as well as look at the thermal properties (ie. melting, decomposition) for energetics. We can look at very small thermal events (just fractions of a watt!) using a thermal analysis monitor (TAM), or even go to a larger scale and look at combustion (Parr Bomb Calorimetry) or even detonation (Parr Detonation Calorimeter) all right in our laboratory.
TA Instruments DSC Q100 is a work "beast" of our research group. Whenever we need to acquire thermal trace of existing or newly synthesized material, this is the first instrument to provide us with any type of information. Ease of use and accuracy of measurements make this analytical technique unparalleled in comparison to many other methods. Combined with our in-house developed DSC sealer, it takes advantage of controlled environment and provides us with extra versatility in our routine analysis.
TA Instruments TGA Q5000 – Nicolet 6700 FTIR – MS. This instrument gives us a plethora information about our gas off headspace in IR region, and is designed for high performance sorption analysis of materials. Additionally, if required this instrument can be retrofitted with mass spectrometer to provide mass-to-charge information on samples under investigation. With weight range of 0.1 g, sensitivity of less than 0.1 µg and the temperature range between 5 and 85 °C, we can do most of our applications for energetic materials to identify the evolving gases and match them to our library.
TA Instruments SDT Q600 Simultaneous DSC/TGA. This instruments provides us with the information that is dual in nature, with both the amount of thermal energy evolved and the mass loss of the sample. Whenever we need to achieve higher temperature that DSC can provide us, we turn our attention to the data produced by Q600. The true differential heat flow on the sample can be performed from ambient to 1,500 °C. With heating rates anywhere from 0.1 to 25 °C, sample capacity of up to 200 mg and balance sensitivity of 0.1 µg, we can rely on getting right measurement for even most complex samples.
TA Instruments TAM III Isothermal Calorimeter. Whenever we need to find the binding constants or the heat evolution from our samples we refer to our isothermal calorimeter. With a temperature range from 2 to 150 °C and temperature stability of ±0.0002 °C, this was never easier. Most of the explosive materials and organic compounds have melting points within this region, and it gives us a very reliable data. With baseline stability of 0.02 µW/h and noise level of 2.5 nW, we can observe even smallest of the events without missing any information. Perfusion type of the experiments provide us with the insight of what can happen to our materials, if we mix it with other solvents or analytes. The binding constants can be calculated that way, as well. If sorption experiments are needed to be performed, we can add various gases to the setup. Overall, it is a very versatile instrument, with a capability of performing various types of tests based on our needs – anywhere from nanocalorimeter to macrocalorimeter scale.