BACKGROUND: Tert-butylphenol (TBP) derivatives, antioxidants in adhesives and diabetes devices, may provoke allergic contact dermatitis (ACD).
OBJECTIVE: The objective of this study is to report sensitization to TBP derivatives in medical devices and to highlight that tert-butylhydroquinone (BHQ) and tert-butylcatechol (TBC) are potential screeners in this regard.
METHODS: Fifteen patients with ACD from adhesives and diabetes devices were patch tested to different TBPs: BHQ 1% pet., TBC 0.25% pet., BHA 2% pet., BHT 2% pet., 4-tert-butylphenol (TBP) 1% pet. and 2,4-di-tert-butylphenol (di TBP) 1% pet. The culprit devices (medical adhesives, sanitary pads, diabetes devices) and TBP patch preparations were analysed using gas chromatography-mass spectrometry (GC-MS).
RESULTS: BHQ (9/13), TBC (7/13), and to a lesser extent BHT (3/15), BHA (2/15) and TBP (2/13) gave positive reactions. Seven patients had developed ACD from adhesives and diabetes devices, respectively, and one patient from sanitary pads. GC-MS analyses of the medical devices and patch test materials confirmed the presence of the patch-test positive TBPs, or chemically related derivatives, or, interestingly, tert-butylbenzoquinones (BBQ) were found, that is, spontaneously formed, highly reactive TBP metabolites, likely (pseudo-) cross reacting with the patch tested TBPs.
CONCLUSIONS: TBPs might be overlooked sensitizers in medical devices, and BHQ and TBC are potential screeners in this regard.

A quantitative gas chromatography mass spectrometry (GC/MS) method was developed for delta-9-tetrahydrocannabinol (delta-9-THC), delta-8-tetrahydrocannabinol (delta-8-THC), tetrahydrocannabinolic acid (THCA), and cannabidiol (CBD) in matrices including plant material, liquids and oils, waxes, edibles, and bath and body products. Samples were prepared by homogenization, extraction of the cannabinoids into solvent, liquid/liquid extraction, and derivatization. The GC/MS method was validated from 0.15% to 5.00% (weight basis) to encompass the 0.3% legal distinction between hemp and marijuana. Validation was performed assessing imprecision/bias, calibration model, recovery, interferences, limit of detection, matrix matching, carryover, accuracy, and an assessment of CBD conversion to delta-9-THC. The calibration curves were quadratic weighted 1/x with r2 > 0.990. The method had a detection limit of 0.075% in plant material for each analyte. Analyte recovery was greater than 70% in plant material. Carryover was not observed up to concentrations equivalent to 100% analyte, and no forensically significant conversion of CBD to delta-9-THC was observed. One cannabinoid isomer, 9(R)-delta-7-tetrahydrocannabinol (9(R)-delta-7-THC), was determined to interfere with the quantitation of delta-9-THC, but could be differentiated based on mass spectrum. The method was determined to be suitable for quantitation of delta-9-THC, delta-8-THC, delta-9-THCA, and CBD and was able to differentiate hemp samples from marijuana samples.

UNASSIGNED: SN-38 (7-ethyl-10-hydroxycamptothecin), the active metabolite of irinotecan, has been extensively studied in drug delivery systems. However, its impact on neural metabolism remains unclear. This study aims to investigate the toxic effects of SN-38 on mouse brain metabolism.
UNASSIGNED: Male mice were divided into an SN-38 group and a control group. The SN-38 group received SN-38 (20 mg/kg/day) via intraperitoneal injection, while the control group was given an equal volume of a blank solvent mixture (DMSO and saline, ratio 1:9). Gas chromatography-mass spectrometry (GC-MS) was employed to analyze differential metabolites in the cortical and hippocampal regions of the SN-38-treated mice.
UNASSIGNED: SN-38 induced metabolic disturbances in the central nervous system. Eighteen differential metabolites were identified in the hippocampus and twenty-four in the cortex, with six common to both regions. KEGG pathway enrichment analysis revealed statistically significant alterations in six metabolic pathways in the hippocampus and ten in the cortex (P<0.05).
UNASSIGNED: This study is the first to demonstrate the neurotoxicity of SN-38 in male mice through metabolomics. Differential metabolites in the hippocampal and cortical regions were closely linked to purine metabolism, pyrimidine metabolism, amino acid metabolism, and glyceride metabolism, indicating disruptions in the blood-brain barrier, energy metabolism, and central signaling pathways.

The introduction of invasive fish species to aquatic ecosystems has been demonstrated to cause disastrous ecological effects. Current conservation strategies regard rotenone-containing piscicide formulations, such as commercial product CFT Legumine, as a potentially viable alternative to the cumbersome traditional approaches to fish eradication. This consideration relies on the fast degradation of rotenone and its relatively rapid dissipation from the environment. Piscicide treatments in fragile aquatic ecosystems should thus monitor not only rotenone concentrations following application, but also other byproducts and degradation products. We present a methodology for the analysis of rotenoids in fresh and brackish waters that addresses two main challenges: the accurate determination of applied concentrations in different salinity concentrations by performing a simplified on-site solid-phase extraction, overcoming the fast degradation of rotenone in sample storage conditions, and the selective analysis of rotenoid byproducts and degradation products by gas chromatography coupled to mass spectrometry. Limits of quantification were below the ecological no-effect concentration of rotenone (2 µg/L) and average recoveries exceeded 80%. Accuracy (compared to expected values) and precision (deviation of replicates) ranged from 78 to 103% and 3 to 14%, respectively, across various rotenoid concentrations. These metrics are more than satisfactory for the intended application of this simplified procedure. The method was applied to piscicide-treated samples, revealing significant and fast degradation of parent rotenoids in storage conditions, as well as a non-negligible accumulation of rotenone in the particulate fraction of water that could impact the effectivity of eradication efforts.

Data processing and data extraction are the first, and most often crucial, steps in metabolomics and multivariate data analysis in general. There are several software solutions for these purposes in GC-MS metabolomics. It becomes unclear which platform offers what kind of data and how that information influences the analysis\'s conclusions. In this study, selected analytical platforms for GC-MS metabolomics profiling, SpectConnect and XCMS as well as MestReNova software, were used to process the results of the HS-SPME/GC-MS aroma analyses of several blackberry varieties. In addition, a detailed analysis of the identification of the individual components of the blackberry aroma club varieties was performed. In total, 72 components were detected in the XCMS platform, 119 in SpectConnect, and 87 and 167 in MestReNova, with automatic integral and manual correction, respectively, as well as 219 aroma components after manual analysis of GC-MS chromatograms. The obtained datasets were fed, for multivariate data analysis, to SIMCA software, and underwent the creation of PCA, OPLS, and OPLS-DA models. The results of the validation tests and VIP-pred. scores were analyzed in detail.

Five rootstock cultivars of differing vigor: vigorous (\'Atlas™\' and \'Bright\'s Hybrid® 5\'), standard (\'Krymsk® 86\' and \'Lovell\') and dwarfing (\'Krymsk® 1\') grafted with \'Redhaven\' as the scion were studied for their impact on productivity, mid-canopy photosynthetic active radiation transmission (i.e., light availability) and internal fruit quality. Αverage yield (kg per tree) and fruit count increased significantly with increasing vigor (trunk cross sectional area, TCSA). Α detailed peach fruit quality analysis on fruit of equal maturity (based on the index of absorbance difference, IAD) coming from trees with equal crop load (no. of fruit cm-2 of TCSA) characterized the direct impact of rootstock vigor on peach internal quality [dry matter content (DMC) and soluble solids concentration (SSC)]. DMC and SSC increased significantly with decreasing vigor and increasing light availability, potentially due to reduced intra-tree shading and better light distribution within the canopy. Physiologically characterized peach fruit mesocarp was further analyzed by non-targeted metabolite profiling using gas chromatography mass spectrometry (GC-MS). Metabolite distribution was associated with rootstock vigor class, mid-canopy light availability and fruit quality characteristics. Fructose, glucose, sorbose, neochlorogenic and quinic acids, catechin and sorbitol were associated with high light environments and enhanced quality traits, while sucrose, butanoic and malic acids related to low light conditions and inferior fruit quality. These outcomes show that while rootstock genotype and vigor are influencing peach tree productivity and yield, their effect on manipulating the light environment within the canopy also plays a significant role in fruit quality development.

The detection of explosives and explosive devices based on the volatile compounds they emit is a long-standing tool for law enforcement and physical security. Toward that end, solid-phase microextraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS) has become a crucial analytical tool for the identification of volatiles emitted by explosives. Previous SPME studies have identified many volatile compounds emitted by common explosive formulations that serve as the main charge in explosive devices. However, limited research has been conducted on initiators like fuses, detonating cords, and boosters. In this study, a variety of SPME fiber coatings (i.e., polydimethylsiloxane (PDMS), polydimethylsiloxane/divinylbenzene (PDMS/DVB), divinylbenzene/carboxin/polydimethylsiloxane (DVB/CAR/PDMS), and carboxin/polydimethylsiloxane (CAR/PDMS)) were employed for the extraction and analysis of volatiles from Composition C-4 (cyclohexanone, 2-ethyl-1-hexanol, and 2,3-dimethyl-2,3-dinitrobutane (DMNB)) and Red Dot double-base smokeless powder (nitroglycerine, phenylamine). The results revealed that a PDMS/DVB fiber was optimal. Then, an assortment of explosive items (i.e., detonation cord, safety fuse, slip-on booster, and shape charge) were analyzed with a PDMS/DVB fiber. A variety of volatile compounds were identified, including plasticizers (tributyl acetyl citrate, N-butylbenzenesulfonamide), taggants (DMNB), and degradation products (2-ethyl-1-hexanol).

Dust is a sink for flame retardants, which are added to a myriad of consumer products in residential spaces. Organophosphate esters (OPEs) and brominated flame retardants (BFRs) are two classes of flame retardants that are frequently used in consumer products and consequently found in dust. In this present work, a novel solvent-limited microextraction technique, which we detailed in a companion study, was applied for the determination of four OPEs and two BFRs with limits of quantitation at the ng/g level by gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry from n = 47 air filter dust samples collected from forced air HVAC systems. Levels of the BFRs, including tetrabromobisphenol-A and its derivative tribromobisphenol-A, were found at levels <4 μg/g and not frequently detected. Conversely, all four OPEs were detected in all air filter dust samples. Total OPE load was dominated by tris(2,4-di-tert-butylphenyl) phosphate, T24DtBPP, a novel OPE not widely examined in the literature. Comparison of individual and total OPE concentrations to residential characteristics revealed statistically significant relationships to location of the home and dominant flooring type. Overall, this study motivates future work in examining the whole house exposome using air filter dust as a passive sampling regime with more examination of T24DtBPP loads within other indoor spaces.

Biogenic volatile organic compounds (bVOCs), synthesised by plants, are important mediators of ecological interactions that can also undergo a series of reactions in the atmosphere. Ground-level ozone is a secondary pollutant generated through sunlight-driven reactions between nitrogen oxides (NOx) and VOCs. Its levels have increased since the industrial revolution and reactions involving ozone drive many chemical processes in the troposphere. While ozone precursors often originate in urban areas, winds may carry these hundreds of kilometres, causing ozone formation to also occur in less populated rural regions. Under elevated ozone conditions, ozonolysis of bVOCs can result in quantitative and qualitative changes in the gas phase, reducing the concentrations of certain bVOCs and resulting in the formation of other compounds. Such changes can result in disruption of bVOC-mediated behavioural or ecological interactions. Through a series of gas-phase experiments using Gas Chromatography Mass Spectrometry (GC-MS) and Proton Transfer Reaction Mass Spectrometry (PTR-MS), we investigated the products and their yields from the ozonolysis of a range of ubiquitous bVOCs, which were selected because of their importance in mediating ecological interactions such as pollinator and natural enemy attraction and plant-to-plant communication, namely: (E)-β-ocimene, isomers of α and β-farnesene, α-terpinene and 6-methyl-5-hepten-2-one. New products from the ozonolysis of these compounds were identified, and the formation of these compounds is consistent with terpene-ozone oxidation mechanisms. We present the degradation mechanism of our model bVOCs and identify their reaction products. We discuss the potential ecological implications of the degradation of each bVOC and of the formation of reaction products.

Due to the overall low abundance of volatile compounds in exhaled breath, it is necessary to preconcentrate the sample prior to traditional thermal desorption (TD) gas chromatography mass spectrometry analysis. While certain aspects of TD tubes, such as volatile storage, have been evaluated, many aspects remain uncharacterized. Two common TD tubes, Tenax TA and Biomonitoring 5TD tubes, were evaluated for background content and flow rate variability. The data illustrate that the Biomonitoring 5TD tubes have the highest number (23) and abundance of background contamination greater than 3x the mean noise when compared to Tenax TA (13) and empty tubes (9). Tentative identifications of the compounds in the background contamination experiment show that greater than 59% (16/27) of the compounds identified have been reported in the breath literature. The data illustrate the TD tube background abundance could account for more than 70% of the chromatographic signal from exhaled breath for these select compounds. Flow rate measurements of 200 Tenax TA and 200 Biomonitoring 5TD tubes show a large range in measured flow rates among the TD tubes (Tenax: 252.9-284.0 ml min-1, 5TD: 220.6-255.1 ml min-1). Finally, TD tubes of each type, Tenax TA and Biomonitoring 5TD, previously established to have high, medium, and low flow rates, show insignificant differences (p> 0.05) among the tubes of different flow rates, using both gas standards and an exhaled breath from a peppermint experiment. Collectively, these results establish overall background compounds attributed to each TD tube type tested. Additionally, while measured flow rate variability is present and plausibly impacts exhaled breath results, the data demonstrate no statistically significant difference was observed between tubes showing high, medium, and low flow rates from two separate sample types.