Application of a Modified 3D-PCSI-MS Ion Source to On-Site, Trace Evidence Processing via Integrated Vacuum Collection.

Trace evidence, including hair, fibers, soil/dust, and gunshot residue (GSR), can be recovered from a crime scene to help identify or associate a suspect with illegal activities via physical, chemical, and biological testing. Vacuum collection is one technique that is employed in recovering such trace evidence but is often done so in a targeted manner, leaving other complementary, chemical-specific information unexamined. Here, we describe a modified 3D-printed cone spray ionization (3D-PCSI) source with integrated vacuum collection for on-site, forensic evidence screening, allowing the processing of targeted physical traces and nontargeted chemical species alike. The reported form factor allows sample collection, onboard extraction, filtration, and spray-based ionization in a singular vessel with minimal handling of evidence by the operator. Utilizing authentic forensic evidence types and portable MS instrumentation, this new method was characterized through systematic studies that replicate CSI applications. Reliability in the form of false positive/negative response rates was determined from a modest, user-blinded data set, and other attributes, such as collection efficacy and detection limit, were examined.

From the laboratory to the field: Chemical analysis of colored smoke pyrotechnic formulations via mass spectrometry techniques.

Smoke dyes are complex molecular systems that have the potential to form many molecular derivatives and fragments when deployed. The chemical analysis of smoke samples is challenging due to the adiabatic temperature of the pyrotechnic combustion and the molecular complexity of the physically dispersed reaction products. Presented here is the characterization of the reaction byproducts of a simulant Mk124 smoke signal on a multigram scale, which contain the dye disperse red 9 (1-(methylamino)anthraquinone), by ambient ionization mass spectrometry. Our previous work has examined the thermal decomposition of a simplified smoke system consisting of disperse red 9, potassium chlorate, and sucrose by anaerobic pyrolysis gas chromatography mass spectrometry performed at the laboratory milligram scale. The results from the lab scale test were compared with a fully functioned Mk124 in the field. To achieve this, Mk124 smokes were functioned in the presence of sampling swabs that collected byproduct residues from the smoke plume in the ambient environment. These swabs were then analyzed using ambient ionization mass spectrometry to identify the expended pyrotechnic residues, with particular interest in halogenated species. Previous work determined the toxicity of unforeseen byproducts identified on the laboratory scale, which were also detected in the field demonstrating the correlation of the laboratory testing to the fielded systems. By understanding the chemical composition of smokes and their reaction products, potential toxicity effects can be easily assessed, leading to safer formulations with improved performance. These results can help assess how smoke byproducts may impact Warfighter performance, personnel health, and the environment.

Rapid screening of high-priority N-nitrosamines in pharmaceutical, forensic, and environmental samples with paper spray ionization and filter cone spray ionization-mass spectrometry.

RATIONALE: The burgeoning concern of N-nitrosamine (NAM) contamination found in various pharmaceutical compositions has increased the demand for rapid and reliable screening methods to better assess the breadth of the problem. These carcinogenic compounds are also found in food, water, and soil, and they have been used in poison-related homicides. METHODS: A combination of complementary, ambient ionization methods, paper spray ionization (PSI) and filter cone spray ionization (FCSI)-mass spectrometry (MS), was characterized towards trace-level residue screening of select NAMs (e.g., N-nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosodibutylamine) directly from complex and problematic matrices of interest, including prescription and over-the-counter tablets, drinking water, soil, and consumable goods. Spectral data for analyte confirmation and detection limit studies were collected using a Thermo LCQ Fleet ion trap mass spectrometer. RESULTS: PSI-MS and FCSI-MS readily produced mass spectral data marked by their simplicity (e.g., predominantly protonated molecular ions observed) and congruence with traditional electrospray ionization mass spectra in under 2 min. per sample. Both methods proved robust to the complex matrices tested, yielding ion signatures for target NAMs, as well as active pharmaceutical ingredients for analyzed tablets, flavorants inherent to food products, etc. Low part-per-million detection limits were observed but were shown dependent on sample composition. CONCLUSIONS: PSI-MS and FCSI-MS were successful in detecting trace-level NAMS in complex liquid- and solid-phase matrices with little to no prior preparation. This work suggests that these methodologies can provide a means for assessing problematic pharmaceutical adulterants/degradants for expedited quality control, as well as enhancing environmental stewardship efforts and forensic investigations.

Detection and toxicity modeling of anthraquinone dyes and chlorinated side products from a colored smoke pyrotechnic reaction.

"Green" pyrotechnics seek to remove known environmental pollutants and health hazards from their formulations. This chemical engineering approach often focuses on maintaining performance effects upon replacement of objectionable ingredients, yet neglects the chemical products formed by the exothermic reaction. In this work, milligram quantities of a lab-scale pyrotechnic red smoke composition were functioned within a thermal probe for product identification by pyrolysis-gas chromatography-mass spectrometry. Thermally decomposed ingredients and new side product derivatives were identified at lower relative abundances to the intact organic dye (as the engineered sublimation product). Side products included chlorination of the organic dye donated by the chlorate oxidizer. Machine learning quantitative structure-activity relationship models computed impacts to health and environmental hazards. High to very high toxicities were predicted for inhalation, mutagenicity, developmental, and endocrine disruption for common military pyrotechnic dyes and their analogous chlorinated side products. These results underscore the need to revise objectives of "green" pyrotechnic engineering.

Accelerated synthesis of energetic precursor cage compounds using confined volume systems.

Confined volume systems, such as microdroplets, Leidenfrost droplets, or thin films, can accelerate chemical reactions. Acceleration occurs due to the evaporation of solvent, the increase in reactant concentration, and the higher surface-to-volume ratios amongst other phenomena. Performing reactions in confined volume systems derived from mass spectrometry ionization sources or Leidenfrost droplets allows for reaction conditions to be changed quickly for rapid screening in a time efficient and cost-saving manner. Compared to solution phase reactions, confined volume systems also reduce waste by screening reaction conditions in smaller volumes prior to scaling. Herein, the condensation of glyoxal with benzylamine (BA) to form hexabenzylhexaazaisowurtzitane (HBIW), an intermediate to the highly desired energetic compound 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20), was explored. Five confined volume systems were compared to evaluate which technique was ideal for forming this complex cage structure. Substituted amines were also explored as BA replacements to screen alternative cage structure intermediates and evaluate how these accelerated techniques could apply to novel reactions, discover alternative reagents to form the cage compound, and improve synthetic routes for the preparation of CL-20. Ultimately, reaction acceleration is ideal for predicting the success of novel reactions prior to scaling up and determining if the expected products form, all while saving time and reducing costs. Acceleration factors and conversion ratios for each reaction were assessed by comparing the amount of product formed to the traditional bulk solution phase synthesis.

Rapid, in situ detection of chemical warfare agent simulants and hydrolysis products in bulk soils by low-cost 3D-printed cone spray ionization mass spectrometry.

Chemical warfare agents (CWAs) are toxic chemicals that have been used as disabling or lethal weapons in war, terrorist attacks, and assasinations. The Chemical Weapons Convention (CWC) has prohibited the use, development, production, and stockpiling of CWAs since its initiation in 1997, however, the threat of deployment still looms. Detection of trace CWAs post-deployment or post-remediation, in bulk matrices such as soil, often requires lengthy sample preparation steps or extensive chromatographic separation times. 3D-printed cone spray ionization (3D-PCSI), an ambient ionization mass spectrometric (MS) technique, provides a rapid, simple, and low-cost method for trace CWA analysis in soil matrices for both in-laboratory and in-field detection. Described here is the utilization of conductive 3D-printed cones to perform both rapid sampling and ionization for CWA simulants and hydrolysis products in eight solid matrices. The analysis of trace quantities of CWA simulants and hydrolysis products by 3D-PCSI-MS coupled to both a commercial benchtop system and a field-portable MS system is detailed. Empirical limits of detection (LOD) for CWA simulants on the benchtop MS ranged from 100 ppt to 750 ppb and were highly dependant on solid matrix composition, with the portable system yielding similar spectral data from alike matrices, albeit with lower sensitivity.

Rapid, low-cost, and in-situ analysis of per- and polyfluoroalkyl substances in soils and sediments by ambient 3D-printed cone spray ionization mass spectrometry.

A rapid method to empirically determine the presence of trace per- and polyfluoroalkyl substances (PFAS) in solid media, such as soils, sands, and sediments, without any sample preparation, through ambient ionization mass spectrometry (MS), is described. 3D-printed cone spray ionization (3D-PCSI) is an ambient ionization technique that employs a 3D-printed conductive plastic cone to perform both sampling and ionization. The 3D-PCSI sources are fabricated in the shape of a hollowed square pyramid to hold bulk matrices, and consist of rigid walls to aid in the uniformity and consistency of sampling and ionization. Solid samples are placed within the hollowed pyramid and a solvent is added to perform an in-situ extraction, followed by spray-based ionization when a voltage is applied. The low cost of 3D-printing, its reproducibility at scale, and lack of sample preparation, enables 3D-PCSI-MS to rapidly and efficiently screen for trace PFAS, in-situ, in bulk samples. Demonstrated here is the detection of trace PFAS that were doped into six different soil and sediment matrices, by 3D-PCSI-MS, to validate the universality of the method, irrespective of matrix composition. All PFAS were identified by their indicative MS3 spectra and ranged in detection limits from 100 ppt to 10 ppb depending on the compound and soil classification. Legacy aqueous film forming foams (AFFF) were analyzed in soil by 3D-PCSI-MS, as were soil samples collected around an AFFF testing facility. The sampling rate for 3D-PCSI-MS was less than 2 min per sample, demonstrating the applicability to high-throughput mapping of a contaminated area.

The current role of mass spectrometry in forensics and future prospects.

Mass spectrometry (MS) techniques are highly prevalent in crime laboratories, particularly those coupled to chromatographic separations like gas chromatography (GC) and liquid chromatography (LC). These methods are considered "gold standard" analytical techniques for forensic analysis and have been extensively validated for producing prosecutorial evidentiary data. However, factors such as growing evidence backlogs and problematic evidence types (e.g., novel psychoactive substance (NPS) classes) have exposed limitations of these stalwart techniques. This critical review serves to delineate the current role of MS methods across the broad sub-disciplines of forensic science, providing insight on how governmental steering committees guide their implementation. Novel, developing techniques that seek to broaden applicability and enhance performance will also be highlighted, from unique modifications to traditional hyphenated MS methods to the newer "ambient" MS techniques that show promise for forensic analysis, but need further validation before incorporation into routine forensic workflows. This review also expounds on how recent improvements to MS instrumental design, scan modes, and data processing could cause a paradigm shift in how the future forensic practitioner collects and processes target evidence.

Identification and Confirmation of Fentanyls on Paper using Portable Surface Enhanced Raman Spectroscopy and Paper Spray Ionization Mass Spectrometry.

Fentanyl and its analogues play a major role in the current opioid epidemic. In particular, these highly potent opioids have become a health hazard due to their use as additives in street drugs. Consequently, rapid on-site procedures for the analysis of this class of seized drugs are needed, especially considering the reported backlog of drug samples, which must undergo identification and confirmation tests to validate the presence of an illicit substance. Paper based devices are cheap sampling and analysis vehicles that have been shown capable of allowing rapid identification and confirmation of drugs of abuse. Modifying paper substrates by imprinting nanoparticles enables surface enhanced Raman spectroscopy (SERS) as well as a second analysis from the same substrate, namely paper spray ionization mass spectrometry. While such a procedure has been described for laboratory use, these illicit drug samples are typically collected in the field and this is where testing should be done. We combine paper SERS and paper spray MS on field-portable and commercial off-the-shelf (COTS) devices for the rapid and low-cost identification and confirmation of fentanyl and its analogues, enabling in situ analysis at the point of seizure of suspect samples. The commercial nature of both instruments moves this technology from the academic realm to a setting where the criminal justice system can realistically utilize it. The capabilities of this single-substrate dual-analyzer technique are further examined by sampling a variety of surfaces of forensic interest.

Screening of the Suzuki Cross-Coupling Reaction Using Desorption Electrospray Ionization in High-Throughput and in Leidenfrost Droplet Experiments.

Suzuki cross-coupling is a widely performed reaction, typically using metal catalysts under heated conditions. Acceleration of the Suzuki cross-coupling reaction has been previously explored in microdroplets using desorption electrospray ionization mass spectrometry (DESI-MS). Building upon previous work, presented here is the use of a high-throughput DESI-MS screening system to identify optimal reaction conditions. Multiple reagents, bases, and stoichiometries were screened using the automated system at rates that approach 10,000 reaction mixture systems per hour. The DESI-MS system utilizes reaction acceleration in microdroplets to allow rapid screening. The results of screening of an array of reaction mixtures using this technique are presented as product ion images via standard MS imaging software, facilitating quick readout. Instructive comparisons are provided with another method of generating droplets for reaction acceleration-the Leidenfrost technique. Acceleration factors greater than 200 were measured for brominated substrates, paralleling the DESI-MS results. Acceleration factors dropped to near unity with highly substituted pyridines, attributable to a steric effect. The reaction proceeded in the absence of a base in Leidenfrost droplets although no product formation was seen without base in the bulk or in the DESI-MS screening experiments. These differences between Leidenfrost chemistry and the bulk and in droplets formed in high-throughput DESI are tentatively attributed to extremes of pH associated with the surfaces of Leidenfrost droplets.

Quantitative Swab Touch Spray Mass Spectrometry for Oral Fluid Drug Testing.

Simultaneous determination of 30 common drugs of abuse, including opioids, benzodiazepines, fentanyl derivatives, methamphetamines, cocaine, substituted methylenedioxyphenethylamines, cathinones, antidepressants, and antipsychotics, in neat oral fluid was carried out using touch spray mass spectrometry from volumetric absorptive microsampling swabs. A simple and rapid (<2 min per sample) method using multiple reaction monitoring was developed and fully validated, yielding satisfactory analytical performance. Minimal sample volumes (10 µL) were used, and neither sample transfer nor preparation steps were required. Most detection limits were below 5 ng/mL from the complex drug mixture in the biological matrix. Simulations of in vivo sampling were carried out and acceptable quantitative results were obtained even under these conditions, indicating the potential of this technique for fast and noninvasive point-of-care drug testing in clinical or forensic settings.

Solubility of hydrocarbon oils in alcohols (≤C6) and synthesis of difusel carbonate for degreasing.

The empirical solubility of hydrocarbon fluids, polyalphaolefin (PAO) and mineral oil, in thirteen small molecular weight alcohols (C1-C6) was determined. Butanols, pentanols, and 1-hexanol could dissolve up to PAO-10 and mineral oil. tert-Pentanol and 1-hexanol could also dissolve high-viscosity PAO-150. The dialkyl carbonate of fusel oil (DFC) was synthesized from dimethyl carbonate in 69% yield. DFC had excellent non-polar solubility and could dissolve PAO-150 and several common industrial lubricants. The flash point of DFC was 93 °C, more than twice that of isoamyl alcohol. DFC had net heating value of 30.47 MJ kg-1, nearly double that of dimethyl carbonate. However, its derived cetane number of 22.8 indicates DFC could not be used directly as diesel fuel.

Ion Mobility-Mass Spectrometry Using a Dual-Gated 3D Printed Ion Mobility Spectrometer.

Described herein is the development of a 3D-printed drift-tube ion mobility spectrometer (IMS) which operates in the open air and is capable of being coupled to any mass spectrometer. The IMS possesses one electrospray focusing electrode, 31 drift electrodes with 7 mm inner diameters, and 2 ion gates at opposite ends of the IMS, totaling 109 mm in length. The second ion gate was timed with respect to the first ion gate to transmit portions of the separating ion packets to the MS at specified time intervals. By scanning the second ion gate and acquiring mass spectra during each time interval, we reconstructed ion mobility chronograms using mass spectra. Resolving powers of up to 45 were acquired using tetraalkylammonium cations. Separation is also demonstrated for solutions of amphetamines, opioids (fentanyls/fentanils), and bradykinin and angiotensin II. The highest mobility resolving powers were obtained when the injection times of the first and second ion gates were 0.3 and 1.0 ms, respectively. Experiments were performed on both an ion trap and triple quadruple mass analyzer to showcase the adaptability of the plastic IMS. Insights were gained into how ions separate in the open air compared to vacuum conditions with pure gas.

Forensic Sampling and Analysis from a Single Substrate: Surface-Enhanced Raman Spectroscopy Followed by Paper Spray Mass Spectrometry.

Sample preparation is the most common bottleneck in the analysis and processing of forensic evidence. Time-consuming steps in many forensic tests involve complex separations, such as liquid and gas chromatography or various types of extraction techniques, typically coupled with mass spectrometry (e.g., LC-MS). Ambient ionization ameliorates these slow steps by reducing or even eliminating sample preparation. While some ambient ionization techniques have been adopted by the forensic community, there is significant resistance to discarding chromatography as most forensic analyses require both an identification and a confirmation technique. Here, we describe the use of a paper substrate, the surface of which has been inkjet printed with silver nanoparticles, for surface enhanced Raman spectroscopy (SERS). The same substrate can also act as the paper substrate for paper spray mass spectrometry. The coupling of SERS and paper spray ionization creates a quick, forensically feasible combination.

Novel Selectivity-Based Forensic Toxicological Validation of a Paper Spray Mass Spectrometry Method for the Quantitative Determination of Eight Amphetamines in Whole Blood.

Paper spray tandem mass spectrometry is used to identify and quantify eight individual amphetamines in whole blood in 1.3 min. The method has been optimized and fully validated according to forensic toxicology guidelines, for the quantification of amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxy-N-methylamphetamine (MDMA), 3,4-methylenedioxy-N-ethylamphetamine (MDEA), para-methoxyamphetamine (PMA), para-methoxymethamphetamine (PMMA), and 4-fluoroamphetamine (4-FA). Additionally, a new concept of intrinsic and application-based selectivity is discussed, featuring increased confidence in the power to discriminate the amphetamines from other chemically similar compounds when applying an ambient mass spectrometric method without chromatographic separation. Accuracy was within ±15% and average precision was better than 15%, and better than 20% at the LLOQ. Detection limits between 15 and 50 ng/mL were obtained using only 12 µL of whole blood. Graphical abstract ᅟ.

Simultaneous Online Monitoring of Multiple Reactions Using a Miniature Mass Spectrometer.

Advances in chemical sampling using miniature mass spectrometer technology are used to monitor slow reactions at a frequency of ca. 180 h-1 (on the Mini 12) with no sample carryover and with inline derivatization in the case of poorly ionizing compounds. Moreover, we demonstrate high reproducibility with a relative error of less than 10% for major components. Monitoring is enabled using a continuous-flow nanoelectrospray (CF-nESI) probe contained in a custom-built 3D-printed rotary holder. The holder position is automatically set using a stepper motor controlled by a microcontroller. Reaction progress of up to six reactions, including hydrazone formation and Katritzky transamination, can be monitored simultaneously without carryover for several hours.

Multigenerational Collision-Induced Dissociation for Characterization of Organic Compounds.

There are many cases in which limited information is obtained from a single stage of tandem mass spectrometry (MS2 or MS/MS). For example, isomeric cathinones give similar product ion MS2 spectra, but they can be differentiated by their unique MS3 fragments. Other drugs such as oxycodone and noroxycodone lose water in a single-stage tandem mass spectrometry experiment but give rich structural information in subsequent stages, as do many peptides. Here we utilize multigenerational collision-induced dissociation (CID) on a miniature mass spectrometer and emphasize useful applications. Unique fragmentation patterns consisting of several generations of fragment ions are obtained in these multigenerational spectra, allowing discrimination of cathinone isomers and structural characterization of small molecules, including drugs and peptides, all using a single sequence of ion injection, isolation, and mass scanning.

Mass spectrometric detection of nanoparticle host-guest interactions in cells.

Synthetic host-guest chemistry is a versatile tool for biomedical applications. Characterization and detection of host-guest complexes in biological systems, however, is challenging due to the complexity of the biological milieu. Here, we describe and apply a mass spectrometric method to monitor the association and dissociation of nanoparticle (NP)-based host-guest interactions that integrates NP-assisted laser desorption/ionization (LDI) and matrix assisted laser desoption/ionization (MALDI) mass spectrometry. This LDI/MALDI approach reveals how NP surface functionality affects host-guest interactions in cells, information difficult to achieve using other techniques.