Volatile organic compounds from Bacillus velezensis SEC-482: A novel weapon against pepper southern blight caused by Agroathelia rolfsii.

Volatile organic compounds (VOCs) are natural markers useful in rapid assessment of adverse changes occurring in biological material. The use of an electronic nose seems to be a good, fast, and cheap method to determine particular VOCs. This paper presents a new method determination for VOCs and their concentration based on three sensorgram parameters: maximum of normalized sensor response, reaction time, and cleaning time measured from the end of the test to the half value of the maximum of normalized sensor response. The novelty of the method consists in the use for the first time of two parameters: reaction time and cleaning time measured from the end of the test to the half value of the maximum of normalized sensor response. The VOC sensorgrams at different VOC concentrations (26 to 3,842 ppm) were measured by an electronic nose Food Volatile Compound Analyzer (Agrinose) equipped with eight metal oxide semiconductor sensors dedicated to detect different gases. In the present studies, only six sensors that best respond to the VOCs were used. The highest responses to VOCs were obtained for two sensors-TGS2602 and AS-MLV-P2. The results showed that the dependence between the sensorgram parameters on VOC concentration was well described by a logarithmic curve in the whole range of concentrations. Detailed analysis revealed that the cleaning time increases with an increase in the number of carbon atoms in aliphatic molecules. The principal component analysis (PCA) was used to verify the utility of the new three parameters method in VOCs differentiation. The PCA analysis of these parameters showed that maximum of the normalized sensor response alone, which has been used for identification of particular VOCs so far, could not be regarded as a good parameter used for this purpose. Application of all the three parameters gave the best results in VOC identification. The research indicates that the use of three parameters of a volatile compound instead of only one parameter can allow precise determination of substances. Moreover, the results indicate that the analyzed parameters depend on the chemical structure of VOCs.

Piezoelectric cantilever resonator is one of the most promising platforms for real-time sensing of volatile organic compounds (VOCs). However, it has been a great challenge to eliminate the cross-sensitivity of various VOCs for these cantilever-based VOC sensors. Herein, a virtual sensor array (VSA) is proposed on the basis of a sensing layer of GO film deposited onto an AlN piezoelectric cantilever with five groups of top electrodes for identification of various VOCs. Different groups of top electrodes are applied to obtain high amplitudes of multiple resonance peaks for the cantilever, thus achieving low limits of detection (LODs) to VOCs. Frequency shifts of multiple resonant modes and changes of impedance values are taken as the responses of the proposed VSA to VOCs, and these multidimensional responses generate a unique fingerprint for each VOC. On the basis of machine learning algorithms, the proposed VSA can accurately identify different types of VOCs and mixtures with accuracies of 95.8 and 87.5%, respectively. Furthermore, the VSA has successfully been applied to identify the emissions from healthy plants and "plants with late blight" with an accuracy of 89%. The high levels of identifications show great potentials of the VSA for diagnosis of infectious plant diseases by detecting VOC biomarkers.

Identification of VOCs from natural rubber by different headspace techniques coupled using GC-MS

Hybrid plasmonic aerogel with tunable hierarchical pores for size-selective multiplexed detection of VOCs with ultrahigh sensitivity

Animal manure is considered a valuable organic fertilizer due to its important nutrient content enhancing soil fertility and plant growth in agriculture. Besides its beneficial role as fertilizer, animal manure represents a significant source of volatile organic compounds (VOCs), playing a significant role in atmospheric chemistry. Understanding the composition of VOCs Understanding VOCs from animal manure is crucial for assessing their environmental impact, as they can cause air pollution, odors, and harm to human health and ecosystems. Laboratory studies enhance field measurements by providing a precise inventory of manure emissions, addressing gaps in existing literature. Both approaches complement each other in advancing our understanding of manure emissions. In this context, we conducted an experimental study involving various animal manures (cow, horse, sheep, and goat) taken from a farm in Grignon (near Paris, France). We employed atmospheric simulation chambers within a controlled laboratory environment. The analysis of VOCs involved the combination of Proton Transfer Reaction-Quadrupole ion guide-Time-of-Flight Mass Spectrometry (PTR-QiTOF-MS) and Thermal Desorption-Gas Chromatography-Mass Spectrometry (TD-GC-MS). Using PTR-QiTOF-MS, 368 compounds were detected and quantified within the manure samples. The complementary analysis by TD-GC-MS enhanced our identification of VOCs. Our findings revealed various chemical groups of VOCs, including oxygenated compounds (e.g., ethanol, cresol, acetaldehyde, etc.), nitrogenated compounds (ammonia, trimethylamine, etc.), sulfur compounds (methanethiol, dimethyl sulfide, etc.), aromatic compounds (phenols and indoles), terpenes (isoprene, D-limonene, etc.) and halogenated compounds. Cow manure exhibited the highest VOC emission fluxes, followed by goat, sheep, and horse manures. Notably, oxygenated VOCs were dominant contributors to total VOC emission fluxes in all samples. Statistical analysis highlighted the distinct nature of cow manure emissions, characterized by oxygenated compounds and nitrogenated compounds. In addition, goat manure was isolated from the other samples with high emissions of compounds having both oxygen and nitrogen atoms in their molecular formulas (e.g., CH3NO2). The experimental dataset obtained in this study provides an inventory reference for both VOCs and their emission fluxes in animal manures. Furthermore, it highlights odorant compounds and VOCs that serve as atmospheric aerosol precursor. Future studies can explore the effectiveness of various manure treatment methods to promote sustainable agriculture practices.

IntroductionBreath Volatile organic compounds (VOCs) are promising biomarkers for clinical purposes due to their unique properties. Translation of VOC biomarkers into the clinic depends on identification and validation: a challenge requiring collaboration, well-established protocols, and cross-comparison of data. Previously, we developed a breath collection and analysis method, resulting in 148 breath-borne VOCs identified.ObjectivesTo develop a complementary analytical method for the detection and identification of additional VOCs from breath. To develop and implement upgrades to the methodology for identifying features determined to be “on-breath” by comparing breath samples against paired background samples applying three metrics: standard deviation, paired t-test, and receiver-operating-characteristic (ROC) curve.MethodsA thermal desorption (TD)-gas chromatography (GC)-mass spectrometry (MS)-based analytical method utilizing a PEG phase GC column was developed for the detection of biologically relevant VOCs. The multi-step VOC identification methodology was upgraded through several developments: candidate VOC grouping schema, ion abundance correlation based spectral library creation approach, hybrid alkane-FAMES retention indexing, relative retention time matching, along with additional quality checks. In combination, these updates enable highly accurate identification of breath-borne VOCs, both on spectral and retention axes.ResultsA total of 621 features were statistically determined as on-breath by at least one metric (standard deviation, paired t-test, or ROC). A total of 38 on-breath VOCs were able to be confidently identified from comparison to chemical standards.ConclusionThe total confirmed on-breath VOCs is now 186. We present an updated methodology for high-confidence VOC identification, and a new set of VOCs commonly found on-breath.

Raman system for sensitive and selective identification of volatile organic compounds

IntroductionVolatile organic compounds (VOCs) can arise from underlying metabolism and are detectable in exhaled breath, therefore offer a promising route to non-invasive diagnostics. Robust, precise, and repeatable breath measurement platforms able to identify VOCs in breath distinguishable from background contaminants are needed for the confident discovery of breath-based biomarkers.ObjectivesTo build a reliable breath collection and analysis method that can produce a comprehensive list of known VOCs in the breath of a heterogeneous human population.MethodsThe analysis cohort consisted of 90 pairs of breath and background samples collected from a heterogenous population. Owlstone Medical’s Breath Biopsy® OMNI® platform, consisting of sample collection, TD-GC-MS analysis and feature extraction was utilized. VOCs were determined to be “on-breath” if they met at least one of three pre-defined metrics compared to paired background samples. On-breath VOCs were identified via comparison against purified chemical standards, using retention indexing and high-resolution accurate mass spectral matching.Results1471 VOCs were present in > 80% of samples (breath and background), and 585 were on-breath by at least one metric. Of these, 148 have been identified covering a broad range of chemical classes.ConclusionsA robust breath collection and relative-quantitative analysis method has been developed, producing a list of 148 on-breath VOCs, identified using purified chemical standards in a heterogenous population. Providing confirmed VOC identities that are genuinely breath-borne will facilitate future biomarker discovery and subsequent biomarker validation in clinical studies. Additionally, this list of VOCs can be used to facilitate cross-study data comparisons for improved standardization.

Current advanced analytical methods allow for the detection of volatile organic compounds (VOC) levels in blood and enable exploration of VOCs and their potential effects. National Health and Nutrition Examination Survey (NHANES) released data in the public domain for 33 analytes of blood VOC levels for a sample representative of the U.S. population for years 2007–2008. The goal of this study was to use data from NHANES 2007–2008 to evaluate the variability in concentration levels of selected VOC analytes (known toxicants in cigarettes) between the general U.S. population and burn victims with smoke inhalation. After IRB approval, blood samples were obtained from burn victims with smoke inhalation injury at our institution from 2008 to present. NHANES data was used for control comparisons. Subjects in the NHANES dataset were matched to subjects in the burn victim dataset based on age, gender and race in a 1:1 ratio (n=23 per group). The analysis focus was placed on seven biomarkers: benzene (VBZ), toluene (VTO), ethylbenzene (VEB), m-/p-xylene (VXY), o-xylene (VOX), styrene (VST), and 2-5-dimethylfuran (2DF) - all of which are well-known toxicants in tobacco smoke. 1,2-dichloroethane (V2A) is not associated with tobacco smoke but was included as a burn victim positive control. . SAS version 9.4 proc ttest was used for univariate analysis of log transformed values of the seven analytes of interest. Cigarette smokers identified by questionnaire were found to have significantly higher blood VOC levels for the seven smoke biomarkers than non-smokers in NHANES data. However, no significant statistical difference was found in blood VOC levels between smokers and nonsmokers among burn victims. Nevertheless, among the matched data, burn victims with smoke inhalation were found to have statistically significantly higher blood VOC levels for: VBZ (p 0.0258), VOX (p 0.0006), VST (p 0.0010), and positive control V2A (<.0001) than NHANES smokers. Although not statically significant, burn victims with smoke inhalation were also found to have higher blood VOC levels than NHANES smokers for VTO, VEB and VXY. The data presented here add to the knowledge about exposure of VOCs among house-fire burn victims with smoke inhalation injury. The most significant finding of this study was that smoke inhalation from house-fire was associated with relatively higher levels of VOC toxicants when compared to cigarette smokers of the U.S. general population. Further investigation is warranted to determine if there is a correlation of elevated VOCs and clinical prognosis. Identification of VOCs that may exacerbate smoke inhalation injury may help develop more sensitive diagnostic tools to help determine severity and/or outcome of an individual’s smoke inhalation injury.

Aroma in food plays an important role in food perception and acceptance, which depends on various mixtures of volatile organic compounds (VOCs). Moreover, VOCs are of great significance for aroma identification. In this study, headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS) technology was used to determine the VOCs in 10 pear syrups. A total of 127 VOCs were quantitatively determined, including 9 common VOCs and 46 characteristic VOCs of 10 pear syrups. The pear syrups were divided into three categories by cluster analysis, and thirty-eight differential VOCs were obtained using orthogonal partial least squares discrimination analysis (OPLS-DA) and fourteen key VOCs were selected by odor activity value (OAV). It was revealed that the key and common aroma components of pear syrups were butanoic acid, methyl ester, 2-methyl-, methyl ester and Hexanoic acid, and ethyl ester. The characteristic and differential VOCs were 10-Undecen-1-ol, Hexadecanal, n-Propylacetate, Cyclohexanol, 5-methyl-2-(1-methylethyl)-, (1S,2R,5S)-, Methional, Disulfide, dimethyl, 8-Nonenoic acid, ethyl ester, Naphthalene, 1,2-dihydro-1,1,6-trimethyl-, 3H-Purin-6-amine, N,N,3-trimethyl-, 2-Octanol,2,6-dimethyl-, Furyl hydroxymethyl ketone, Heptane, 2,2,4,6,6-pentamethyl-, and Butanoic acid,2-methyl-,methyl ester. The above results showed that different pear syrups had rich diversity in aroma compounds, with some components being shared among them while others are exclusive to specific syrups.

Exploring eutrophic effects of marine sediments underneath fish cage farms: Insights from changes in eukaryotic and bacterial communities and volatile organic compounds.

Open microalgal ponds used in industrial biomass production are susceptible to a number of biotic and abiotic environmental stressors (e.g., grazers, pathogens, pH, temperature, etc.) resulting in pond crashes with high economic costs. Identification of signature chemicals to aid in rapid, non-invasive, and accurate identification of the stressors would facilitate targeted and effective treatment to save the algal crop from a catastrophic crash. Specifically, we were interested in identifying volatile organic compounds (VOCs) that can be used to as an early diagnostic for algal crop damage. Cultures of Microchloropsis gaditana were subjected to two forms of algal crop damage: (1) active grazing by the marine rotifer, Brachionus plicatilis, or (2) repeated freeze–thaw cycles. VOCs emitted above the headspace of these algal cultures were collected using fieldable solid phase microextraction (SPME) fibers. An untargeted analysis and identification of VOCs was conducted using gas chromatography-mass spectrometry (GC-MS). Diagnostic VOCs unique to each algal crop damage mechanism were identified. Active rotifer grazing of M. gaditana was characterized by the appearance of carotenoid degradation products, including β-cyclocitral and various alkenes. Freeze–thaw algae produced a different set of VOCs, including palmitoleic acid. Both rotifer grazing and freeze–thawed algae produced β-ionone as a VOC, possibly suggesting a common stress-induced cellular mechanism. Importantly, these identified VOCs were all absent from healthy algal cultures of M. gaditana. Early detection of biotic or abiotic environmental stressors will facilitate early diagnosis and application of targeted treatments to prevent algal pond crashes. Thus, our work further supports the use of VOCs for monitoring the health of algal ponds to ultimately enhance algal crop yields for production of biofuel.

Invasive whitefly species in coconut plantations have become a matter of concern in the last half a decade as they cause direct and indirect infestation on the palms. The Rugose spiralling whitefly (RSW), Aleurodicus rugioperculatus Martin infestation was high on Cocos nucifera L. (coconut) followed by Dypsis lutescens (H. Wendl.) (Butterfly palm) and Annona squamosa L. (custard apple). The coconut varieties Malayan Yellow Dwarf and Chowghat Orange Dwarf were observed with higher infestation index while that of West coast tall was the lowest. Higher RSW parasitization levels were observed on Musa paradisiaca L. (banana) and Canna indica L. (Indian shot), with 85.96 and 71.59% parasitization, respectively. Identification of volatile organic compounds (VOCs) between healthy and RSW-infested coconut plants revealed the emission of 56 VOCs from the healthy coconut plant and 47 VOCs from RSW infested plant. 22 VOCs were common in both samples, and 25 VOCs were unique to RSW-infested coconut plants. The presence of 42 VOCs was identified from the headspace extracts of RSW-infested bananas. Differences in the VOCs emitted from RSW-infested banana and coconut plants revealed higher emission of terpenoids like β-Caryophyllene, (E, Z)-2,6-dimethyl-2,4,6-Octatriene, Humulene, α-Pinene, Farnesane, α-Copaene and β-cis-Ocimene from RSW infested banana plants that proved to be more attractive to the parasitoid. Identifying specific blends of volatile compounds influencing Encarsia guadeloupae Viggiani could help to augment the parasitotic for RSW management in coconut plantations.

This work presents development of chemiresistor gas sensor based on polyaniline (PANi) blending with poly(methyl methacrylate) (PMMA) thin film for identification of volatile organic compounds (VOCs) relevant to environmental monitoring. The investigated VOCs are including acetone, methanol, ethanol and ammonia. The gas sensors are prepared by solution mixing between non-conducting form of PANi and PMMA in presence of NMP solution. The mixed solution is spun on aluminum interdigitated electrodes and converted into conducting form using HCl doping. Their sensitivity is measured at room temperature by applying constant voltage and measuring response current in the presence of target gases. The results show that PANi/PMMA blend film has higher surface roughness and porous structure leading to higher response to VOCs gases when compared to pure PANi thin film. The PANi/PMMA blend film exhibits the highest response to ammonia and the lowest to acetone vapor. It response shows little different between ethanol and acetone vapor. The different response characteristics to VOCs of PANi/PMMA blend film indicate that it can be used as active layer for room temperature VOCs sensor.

In recent years, interest has increased regarding the identification of volatile organic compounds (VOCs) for metabolic profiling, human scent identification of the living and deceased, and diagnostic potentials for certain diseases that are known for its association with distinct odor. In this study, a method has been developed that is capable of sampling, identifying, and differentiating the VOCs present in various biological specimens of forensic importance (blood, breath, buccal cells, and urine) taken from the same individuals. The developed method requires a pretreatment step to remove targeted VOCs from the sampling apparatus prior to sampling of the individual specimens. The VOCs collected from the biological specimens were characterized by solid-phase microextraction and gas chromatography/mass spectrometry with ratios of the most abundant and frequent VOCs compared using qualitative and semiquantitative methods. Blood, breath, and buccal cells required extraction procedures ranging from 18 to 21 h in order to optimize the limit of detection, which averaged 5-15 ng across these specimens. The optimal method for measuring urine VOCs was complete in less than an hour; however, the limit of detection was higher with a range of 10-40 ng quantifiable. The demonstrated sensitivity and reproducibility of the methods developed allow for population studies of human scent VOCs from various biological specimen collection kits used in the forensic and clinical fields.