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When a fire is suspected to be intentionally set, fire debris samples can be collected and analyzed for ignitable liquid residues (ILRs). In some cases, samples will contain highly organic substrates such as soil or rotting wood. These substrates will contain a high bacterial load, which can result in systematic and irreversible damage to the ILR due to microbial degradation. This paper explores ways to preserve ILR by sterilizing fire debris samples without interfering with their subsequent analysis. There are many methods reported in the literature for sterilizing soil, such as freezing, irradiation, autoclaving, and various chemical fumigation techniques. However, these methods either do not kill all bacterial species, cannot be easily applied in the field or would interfere with the analysis of the ILRs. For this work, various anti-microbial compounds including triclosan (2,4,4′-trichloro-2′-hydroxydiphenyl ether) were tested for their efficacy at killing bacteria present in the soil. Triclosan was highly effective in qualitative growth studies and was therefore used to measure bacterial growth (or lack thereof) by spectroscopic analysis as well as passive headspace analysis. These experiments showed that triclosan was able to sterilize soil samples in less than 60s, maintain their sterility for at least 77h and preserve gasoline residues on a soil matrix for at least 30 days.

F-500 Encapsulator Agent (EA) is a fire suppression agent that is an alternative to traditional firefighting foams. It is marketed as having the capability to act on all four parts of the fire tetrahedron as well as being environmentally friendly and non-toxic. An internal survey of the use of F-500 EA by fire departments encountered by the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) ignitable liquid detection canine (ILDC) handlers in 2022 showed that this product is not yet in widespread use across the country, but where it has been implemented, it is frequently utilized on a variety of types of fires. Additional agencies are researching the product to determine if it should be adopted. As this product appears to be growing in popularity, it is important to understand whether the use of the product would affect a canine’s ability to detect ignitable liquids or a forensic laboratory’s ability to identify the presence of an ignitable liquid. Burned wood and burned carpet, two commonly encountered substrates, were spiked with gasoline or a heavy petroleum distillate (HPD) and F-500 EA was applied. At various time intervals, ILDC teams surveyed the samples and laboratory analysis was conducted. Results showed that the presence of F-500 EA can negatively affect canine alerts and the laboratory’s ability to identify ignitable liquids. •F-500 Encapsulator Agent appears in data during routine ignitable liquid analysis with passive headspace concentration.•The effect of the product on canine detection and ignitable liquid analysis varied based on substrate and ignitable liquid.•Results show the product has the potential to interfere with canine detection of ignitable liquids and laboratory analysis.

•Hydrophobic pads collect ignitable liquids from the surface of water.•Analysis of petroleum distillates recovered using hydrophobic pads are easily identifiable.•Gasoline recovered from the surface of water using hydrophobic pads shows loss of lower molecular weight compounds. Significant amounts of water are used to extinguish fires, and finding evidence of ignitable liquid residue can be challenging for investigators. Hydrophobic pads have been designed to collect oil-based products from the surface of water and preferentially absorb non-polar compounds while repelling water. In this study hydrophobic pads are used to collect various classifications of ignitable liquids from the surface of water for analysis using passive headspace concentration and GC/MS analysis. Hydrophobic pads were found to be effective in collecting ignitable liquids containing hydrocarbons greater than C8, classifications medium and heavy petroleum distillates, from 10 microliters of ignitable liquids added to the surface of 100 milliliters of water. Gasoline and 50% evaporated gasoline were also recovered using the hydrophobic pads with 25 microliters of sample.

[Display omitted] •ACC is suitable for the extraction and concentration of ignitable liquid residues.•The sampling ability of ACS and ACC are comparable.•The distance between the skin and the sorbent strongly influences the collection.•The space between the hand and the glove or bag impacts the sampling of gasoline. Arsonists may use ignitable liquids to start, accelerate and amplify fires. The sampling of volatiles present on the hands of suspected arsonists is therefore sometimes carried out in the course of the investigation of (possible) deliberate fires. Several collection protocols have been proposed, relying on the concentration of volatiles by the transfer on PVC gloves and further passive headspace extraction with Activated Charcoal Strips (ACS). Previous research findings assessing the use of Activated Carbon Cloth (ACC) – initially developed for the adsorption of gas in military applications – opens the path to new perspectives regarding the extraction and the concentration of ignitable liquid residues in general, and for the sampling on hands in particular. Five alternative methods (four relying on the use of ACC and one on ACS) were considered for the collection of gasoline traces present on the hands and their subsequent analysis by gas chromatography – mass spectrometry. Gasoline was deposited onto the palms of volunteers to study the differences between the collection method using ACS and those using ACC. For the latter, either the volunteer hands were placed in nylon bags with an ACC on the palm or suspended, or, powder-free latex gloves were used, with an ACC on the palm or in a separate extraction, with the glove in a nylon bag and the ACC suspended. The results showed that the background contamination was not distinguishable between ACS and ACC and their sampling ability was comparable. The two methods relying on the deposition of ACC directly on the surface of the palm where gasoline was deposited showed significantly higher collection capacity than other methods, provided that the ACC was in direct contact with the contaminated zone. The results showed that three main factors affected the collection of gasoline on the hands: the distance between the skin and the sorbent (ACC or ACS) in case of direct concentration of volatiles on the sorbent, the exposure time, and the space between the hand and the glove or bag (i.e. the headspace volume). This research opens new perspectives for the sampling of ignitable liquid residues through the use of ACC. It corroborates the perceived potential of ACC for the extraction and concentration of volatile compounds, particularly for fire debris analysis purposes. While the experiments were focused on the collection of gasoline on hands, the results provide valuable information in a more general way for the sampling of fire debris.

Modified atmospheric packaging (MAP) has emerged as a leading postharvest technique to minimize losses and maintain quality of cut products. The present investigation was conducted to design passive MAP for gladiolus spikes to enhance their postharvest life. The harvested spikes (tight bud stage) were packed in low-density polyethylene (LDPE, 150 guage) and polypropylene (PP, 100 gauge) at 5 °C and 10 °C from 4 to 24 days. The MAP design was based on respiration rate and weight of gladiolus spikes, storage temperature, package gas exchange area and desirable in-pack O 2 and CO 2 concentrations (O 2 : 3–5%, CO 2 : 5–8%). The headspace O 2 and CO 2 concentrations (%) in PP package were, respectively, 5.05 and 7.35 at 5 °C, whereas 4.55 and 8.05 at 10 °C after storage for 8 days. Further, the vase life of spikes in these PP package was 13.86 days after 8 days of storage and declined to 8.86 days after 12 days of storage. The gladiolus spikes packed in PP sleeve (120 cm length, 18 cm width and 50 perforations) could be best stored vertically in cold room (5 ± 0.5 °C) for 10 days with acceptable flower quality and vase life up to 13 days as supported by higher membrane stability index, relative water content, total soluble sugars and proteins, and lower lipid peroxidation. Thus, designed MAP gives a window of 7 days (postharvest life of unpacked spikes 16 days and packed 23 days) for market regulation during glut period to earn remunerative prices without any adverse effect on quality.

This investigation was carried out to evaluate the effect of active and passive modified atmosphere packaging on quality and shelf life of yellow bell pepper fruits. Yellow bell pepper fruits were packaged in 150 gauge LDPE packages with oxygen absorbers for active modification and without oxygen absorber for passive modification of headspace and were stored at different temperatures i.e. 5, 10 and 15 °C and RH of 85 ± 5%. Headspace gas concentration within the packages was monitored regularly. The quality of packaged fruits was studied in terms of physiological loss in weight, firmness, total colour difference antioxidant capacity and total phenolic content. The actively modified packages attained steady state levels of 4.8% O2 and 7.1% CO2 on 4th day of storage as compared to passively modified packages in which steady state was not attained even at end of storage period of 12 days. The retention of quality attributes was observed to be higher in active packages than in passive packages. Moreover, the shelf life of actively packaged fruits was enhanced to 28 days as compared to 12 days for passively packaged fruits. The in-pack atmosphere attained in active packages hence proved beneficial in retarding the senescence thereby extending the shelf life.

A HS-SPME method coupled with GC-MS analysis has been developed for simultaneously measuring the concentration of 10 volatile organic compounds (VOCs) (benzene, toluene, ethylbenzene, o- , m- , and p- xylene, methyl tert -butyl ether, ethyl tert -butyl ether, 2-methyl-2-butyl methyl ether, and diisopropyl ether) in urine matrix as a biomonitoring tool for populations at low levels of exposure to such VOCs. These compounds, potentially toxic for human health, are common contaminants of both outdoor and indoor air, as they are released by autovehicular traffic; some of them are also present in environmental tobacco smoke (ETS). Thus, the exposure to these pollutants cannot be neglected and should be assessed. The low limits of detection and quantification (LODs and LOQs <6.5 and 7.5 ng L –1 , respectively) and the high reproducibility (CVs <4 %) make the developed method suited for biomonitoring populations exposed at low levels such as children. Further, the method is cost-effective and low in time-consumption; therefore, it is useful for investigating large populations. It has been applied to children exposed to traffic pollution and/or ETS; the relevant results are reported, and the relevant implications are discussed.

The recovery of low molecular weight oxygenates in fire debris samples is severely compromised by the use of heated passive headspace concentration with an activated charcoal strip, as outlined in ASTM E-1412. The term “oxygenate” is defined herein as a small, polar, organic molecule, such as acetone, methanol, ethanol, or isopropanol, which can be employed as an ignitable liquid and referred to in the ASTM classification scheme as the “oxygenated solvents” class. Although a well accepted technique, the higher affinity of activated carbon strips for heavy molecular weight products over low molecular weight products and hydrocarbons over oxygenated products, it does not allow for efficient recovery of oxygenates such as low molecular weight alcohols and acetone. The objective of this study was to develop and evaluate a novel method for the enhanced recovery of oxygenates from fire debris samples. By optimizing conditions of the heated passive headspace technique, the utilization of zeolites allowed for the successful collection and concentration of oxygenates. The results demonstrated that zeolites increased the recovery of oxygenates by at least 1.5-fold compared to the activated carbon strip and may complement the currently used extraction technique.