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There are many factors that may affect the longevity of or guide the use of canine training aids. Literature to date has mainly focused on identifying the headspace volatiles associated with training aids or odors and only minimal research exists into how different variables may alter those volatiles. The current study examines several factors affecting canine training aids: humidity, air flow, transportation, and operational deployment, using the triacetone triperoxide polymer odor capture-and-release canine training aid (TATP POCR) as the target. The TATP POCR is an absorption-based canine training aid developed to be used to safely train canines to detect the odor of the explosive TATP in operational settings. Comparisons of the TATP POCR to neat TATP are made throughout the manuscript. First, humidity increased the background components of the POCR matrix, as well as the amount of TATP recovered was above the POCR. Humidity thus affected the amount of TATP detected but did not prevent detection. Second, air flow lessened the lifetime of the TATP POCR. Third, the practice of using primary and secondary containment successfully prevented contamination, cross-contamination, and significant target loss, thereby maintaining kit integrity. Finally, the absorption of background odors from training environments was not observed. TATP headspace concentrations between a Deployed and Control POCR kit were not significantly different at time 0 (i.e., upon opening), which suggests that the operational use does not affect the function of the TATP POCR system. This information provides pivotal evidence for explosives detection canine handlers or trainers who utilize the TATP POCR., (© 2024 American Academy of Forensic Sciences.)

Contamination of canine training aids is a pervasive issue that may lead to incorrect canine discrimination of target odors. It is therefore important to properly store training materials to maintain their integrity and efficiency. First, this study demonstrated the potential for contamination using GloGerm™ as a proxy for odor/particulate transfer. Then, eight types of containers were evaluated to determine (1) the ability to prevent odor permeation and (2) the likelihood of maintaining the ab/adsorbed odor. Lastly, a longitudinal study evaluated how the permeation of the target odor changed over time. Analysis occurred using a direct analysis in real-time mass spectrometer (DART-MS) to detect triacetone triperoxide (TATP) from the non-hazardous canine training aid known as the polymer odor capture-and-release (POCR) system. Results showed that Mylar and Opsak bags were most effective for short-term storage, maintaining low levels of ab/adsorption. Over time, the amount of TATP permeating through the primary containers and collecting in a secondary container (i.e., outer packaging) increased at 1 week and decreased thereafter (up to 4 months). The amount of TATP collecting in the primary containers, however, increased up to 1 month and decreased thereafter., (© 2023 American Academy of Forensic Sciences.)

It is generally accepted in the canine detection industry that a barrier (such as a glove) should be used between a human and evidence or canine training aids in order to prevent contamination and cross-contamination as well as protect the handler from hazardous materials. However, no studies exist evaluating this assumption. Further, there is no published literature examining the different types of gloves for their utility in handling evidence or training materials used in canine detection work. This study was the first of its kind to address these gaps in the literature. First, GloGerm™ was used as a proxy for human scent and odor(s)/particulate(s) to visualize potential contamination. Then, three types of gloves (nitrile, two layers of nitrile, latex, and polyethylene) were tested for the permeation of human scent using furfural as a proof of concept, followed by pooled human sweat. Finally, the inherent odor of each glove type was identified. Two analytical techniques were used simultaneously as static and standoff dynamic detection systems, respectively: solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) and direct analysis in real time-mass spectrometry (DART-MS). Using a double layer of nitrile gloves was the most effective in preventing furfural permeation from the analytical standard, while a single layer of nitrile prevented furfural from permeating from human sweat up to 2 h. Polyethylene gloves allowed the highest amount of furfural permeation but had no inherent odor detected. Headspace analysis detected two compounds for nitrile gloves and four compounds for latex gloves, but the nitrile compounds had a higher relative abundance., (© 2022 American Academy of Forensic Sciences.)

Fentanyl HCl is of particular interest in forensic cases but there is a notable gap in literature regarding its analysis. This study utilized a multi-method approach to characterize fentanyl HCl powder, both fresh and following a forced degradation process. Using sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) and direct injection gas chromatography-mass spectrometry (GC-MS), five compounds were identified in fresh fentanyl HCl powder. The identified compounds were: N-phenylpropanamide, 1-phenethyl-4-propionyloxypiperidine (1-P-4-POP), 4-anilino-N-phenethylpiperidine (4-ANPP), acetylfentanyl, and fentanyl; all identified compounds but acetylfentanyl and fentanyl decreased in quantity as the sample was degraded. Fresh headspace samples analyzed with solid phase microextraction (SPME)-GC-MS identified four compounds in common with the powder analyses: N-phenylpropanamide,1-P-4-POP, 4-ANPP, and fentanyl. Acetylfentanyl was not present in the headspace samples, although two additional compounds were: N-phenylacetamide and N-phenethyl-4-piperidinone (NPP). Where direct analysis of degraded fentanyl HCl showed decreased quantities of the identified compounds, headspace samples of the degraded fentanyl HCl resulted in higher quantities, implying that the degradation process drove those compounds to volatilize. Notably, fentanyl was identified in the headspace, implying that this could be an appropriate target for standoff detection. Finally, thermogravimetric analysis (TGA) and differential scanning calorimetry (DCS) confirmed that the forced degradation process had little permanent effect on the powder., (© 2022 American Academy of Forensic Sciences.)

The Controlled Odor Mimic Permeation System (COMPS) was developed to provide a convenient field testing method of odor delivery at controlled and reproducible rates. COMPS are composed of an odorant of interest on an absorbent material sealed inside of a permeable polymer bag. The permeable layer allows for a constant release of the odorant over a given amount of time. The permeable bag is further stored in a secondary, impermeable bag. The double-containment procedure allows for equilibration of the odorant from the permeable bag but within the impermeable outer layer, resulting in an instant and reproducible source of odorant vapor upon removal from the outer packaging. COMPS are used in both olfactory testing for experimental scenarios and for olfactory detection training, such as with detection canines. COMPS can be used to contain a wide range of odorants (e.g., narcotics powders) and provide a controlled release of the associated odorants. Odor availability from COMPS is expressed in terms of permeation rate (i.e., the rate of the odorant vapor released from a COMPS per unit time) and is typically measured by gravimetric means. The permeation rate for a given mass or volume of odorant can be adjusted as needed by varying the bag thickness, surface area, and/or polymer type. The available odor concentration from a COMPS can also be measured by headspace analysis techniques such as solid phase microextraction with gas chromatography/mass spectrometry (SPME-GC/MS).

Operationally-deployed canine detectors are often trained on one or a limited number of materials representing a single target odor, and training frequently occurs using materials of a high purity grade in controlled scenarios with minimal other background odors. Conversely, in the field, canine detectors are expected to generalize and identify variations of the target odor, while discriminating from similar extraneous or background odors. This exemplifies the balance between generalization and discrimination required for effective canine detectors. This research explored the tendency for detection canines to generalize or discriminate between similar odorants. Two groups of related odorants were used in two separate studies; (1) odorants of similar functional groups with differing carbon chains, and (2) odorants of similar carbon chain length but differing functional groups. Within each odorant set, the effect of training was addressed by incrementally increasing the number of odorants each canine was trained to detect. Initially, discrimination increased with increasing molecular dissimilarity in both odorant groups. After further training on additional related odorants, generalization increased across the set of odorants of the same carbon chain length, but there were no significant changes in either generalization or discrimination across the set of odorants of the same functional group. The results suggest that the canines in this study were more likely to generalize across compounds of the same chain length with differing functional group than across compounds of the same functional group, but differing chain lengths. Furthermore, some variation in performance between individual canines indicated that the tendency to generalize differed with experience, breed, and other factors affecting olfaction., (Published by Elsevier B.V.)

A widely recognized limitation in mammalian olfactory research is the lack of current methods for measuring odor availability (i.e., the quantifiable amount of odor presented and thus available for olfaction) of training or testing materials during behavioral or operational testing. This research utilized an existing technology known as Controlled Odor Mimic Permeation Systems (COMPS) to produce a reproducible, field-appropriate odor delivery method that can be analytically validated and quantified, akin to laboratory-based research methods, such as permeation devices that deliver a stable concentration of a specific chemical vapor for instrumental testing purposes. COMPS were created for 12 compounds across a range of carbon chain lengths and functional groups in such a way to produce similar permeation rates for all compounds. Using detection canines as a model, field-testing was performed to assess the efficacy of the method. Additionally headspace concentrations over time were measured as confirmation of odor availability using either externally sampled internal standard-solid phase microextraction-gas chromatography-mass spectrometry (ESIS-SPME-GC-MS) or collection onto a programmable temperature vaporizing (PTV) GC inlet with MS detection. Finally, lifetime usage was considered. An efficient method for producing and measuring reliable odor availabilities across various chemical functional groups was developed, addressing a noted gap in existing literature that will advance canine and other nonhuman mammal research testing., (Published by Oxford University Press on behalf of US Government 2019.)

A novel method for the detection of vaporous products was developed utilizing a derivatizing agent collected onto a cryo-cooled gas chromatograph (GC) inlet, with analysis by gas chromatography-mass spectrometry (GC-MS). The technique was applied to the detection of ammonia, which has been difficult to detect at trace levels, particularly in the presence of other chemical interferents, due to its small mass and high volatility. To address this, the ammonia is derivatized in the inlet with butyl chloroformate to produce butyl carbamate, a compound that is retained by GC columns and compatible with standard GC-MS analysis. This method was then used to quantify the ammonia headspace vapor concentration produced from the dissociation of bulk ammonium nitrate as well as from mixtures with aluminum and petroleum jelly, which are fuels commonly used in homemade explosives (HMEs)., (Published by Elsevier B.V.)

Raffaelea lauricola, a fungus causing a vascular wilt (laurel wilt) in Lauraceae trees, was introduced into the United States in the early 2000s. It has devastated forests in the Southeast and has now moved into the commercial avocado groves in southern Florida. Trained detection canines are currently one of the few successful methods for early detection of pre-symptomatic diseased trees. In order to achieve the universal and frequent training required to have successful detection canines, it is desirable to create accessible, safe, and long-lasting training aids. However, identification of odorants and compounds is limited by several factors, including both the availability of chemicals and the need to present chemicals individually and in combination to detection canines. A method for the separation and identification of volatile organic compounds (VOCs) from environmental substances for the creation of such a canine training aid is presented here. Headspace solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to identify the odors present in avocado trees infected with the R. lauricola phytopathogen. Twenty-eight compounds were detected using this method, with nine present in greater than 80% of samples. The majority of these compounds were not commercially available as standard reference materials, and a canine trial was designed to identify the active odors without the need of pure chemical compounds. To facilitate the creation of a canine training aid, the VOCs above R. lauricola were separated by venting a 0.53mm ID solgel-wax gas chromatography column to the atmosphere. Ten minute fractions of the odor profile were collected on cotton gauze in glass vials and presented to the detection canines in a series of field trials. The canines alerted to the VOCs from the vials that correspond to a portion of the chromatogram containing the most volatile species from R. lauricola. This innovative fractionation and collection method can be used to develop reliable and cost effective canine training aids., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Volatile organic compounds (VOCs) in the headspace of the fungus Raffaelea lauricola have been monitored and identified over a twenty-eight day growth period. R. lauricola is an invasive and phytopathogenic fungus that was first identified in the United States in the mid-2000s. It is believed to be spread by a host beetle, Xyleborus glabratus, and is detrimental both to wild members of the Lauraceae family and to commercial avocado groves particularly in the Southeastern region of the country. The fungus causes the fatal laurel wilt disease, a result of the host tree shutting down its vascular system in order to halt the spread of the fungus. The current study identified the VOCs present in the headspace of R. lauricola over the initial growth stage using headspace solid phase microextracion-gas chromatography-mass spectrometry (HS-SPME-GC-MS). Results revealed the VOC dynamics of the fungus in culture, indicating that the initial growth period of the fungus may coincide with potential responses from the host trees that may recognize and respond to the pathogen when the fungal VOCs are produced as a result of primary metabolic processes. As fungal growth progresses past initial growth phases, the predominant compounds seen in the odor profile are hydrocarbons and terpenes, produced from secondary metabolic processes. The odor profile pattern for the twenty-eight day growth period did change with the stages of growth. Based on the information learned from this pilot study, a discussion is presented of possible host tree reactions to R. lauricola and implications for future experiments., (Copyright © 2017. Published by Elsevier B.V.)