Headspace Air Research Articles

Effect of Pump Operation on Headspace Air Pressure Variation in Sanitary Sewer Systems

AbstractModeling air flow movement in the headspace of sanitary sewers is important for municipalities for sewer corrosion control and odor mitigation. This paper presents the results of field-meas...

Effect of headspace air conditions on total organic acids dissolved in transformer oil

The aim of this work was studying the effect of dissolved oxygen concentration, temperature and humidity level of headspace air on the acidification of insulation oil. The novelty is assessment and classification of those parameters based on the acidity level, induction time and the rate of oil acidifying. Two gas-washers containing insulation oil and deionised water were in contact with the bubbling streams of O2/N2 containing different humidity levels. The acidity of two phases was determined based on TAN number and pH values, respectively. The results revealed that O2/N2 weight ratio, insulator temperature and the level of air humidity control the acidity strength, the induction time of acid production and the rate of oil acidifying, respectively. Reduction of O2/N2 weight ratio in the headspace air decreased the level of the produced organic acids, while reduction of temperature extended the onset time of acid formation. [Received: July 31, 2020; Accepted: January 12, 2021]

Modification of Major Contributors Responsible for Latrine Malodor on Exposure to Hypochlorous Acid: The Potential for Simultaneously Impacting Odor and Infection Hazards to Encourage Latrine Use.

.Open defecation remains a common practice in developing countries and leads to high incidence and prevalence of acute gastroenteritis, which is most often caused by human noroviruses (human NoV). Encouraging the use of toilets and pit latrines is one method of improving sanitation; however, it is often hindered by not only cultural traditions but also from a reluctance to use latrines and toilets due to their odor and impression of uncleanliness. In an effort to establish new means to encourage toilet and latrine use, laboratory experiments tested the ability of hypochlorous acid (HOCl) to modify the malodorous compounds identified in the air in latrines in developing countries (indole, p-cresol, dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS), and butyric acid) and inactivate MS2 bacteriophage, a surrogate for human NoV. After 5 minutes, > 94% of indole, p-cresol, DMDS, and DMTS was modified as determined by high-pressure liquid chromatography in the presence of 100 ppm HOCl. A log10 reduction value (LRV) greater than 6 was seen for MS2 bacteriophage after 5 minutes of exposure to 100 ppm HOCl in solution. Sensory studies indicated that there was a significant difference (P ≤ 0.05) between the untreated and HOCl-treated samples for all five malodorous compounds tested. The findings suggest that introduction of HOCl into the headspace air could encourage latrine and toilet use. Optimization of HOCl dosing in air to accomplish both odor control and reduction of infectious hazards is worthy of further study.

A novel lung alveolar cell model for exploring volatile biomarkers of particle-induced lung injury

Quartz can increase oxidative stress, lipid peroxidation, and inflammation. The objective of this study was to explore the volatile biomarkers of quartz-induced lung injury using a lung alveolar cell model. We exposed the human alveolar A549 cell line to 0, 200, and 500 μg/mL quartz particles for 24 h and used gas chromatography–mass spectrometry to measure the volatile metabolites in the headspace air of cells. We identified ten volatile metabolites that had concentration–response relationships with particles exposure, including 1,2,4-oxadiazole, 5-(4-nitrophenyl)-3-phenyl- (CAS: 28825-12-9), 2,6-dimethyl-6-trifluoroacetoxyoctane (CAS: 61986-67-2), 3-buten-1-amine, N,N-dimethyl- (CAS: 55831-89-5), 2-propanol, 2-methyl- (CAS: 75-65-0), glycolaldehyde dimethyl acetal (CAS: 30934-97-5), propanoic acid, 2-oxo-, ethyl ester (CAS: 617-35-6), octane (CAS: 111-65-9), octane, 3,3-dimethyl- (CAS: 4110-44-5), heptane, 2,3-dimethyl- (CAS: 3074-71-3) and ethanedioic acid, bis(trimethylsilyl) ester (CAS: 18294-04-7). The volatile biomarkers are generated through the pathways of propanoate and nitrogen metabolism. The volatile biomarkers of the alkanes and methylated alkanes are related to oxidative and lipid peroxidation of the cell membrane. The lung alveolar cell model has the potential to explore the volatile biomarkers of particulate-induced lung injury.

Use of biochar for the sorption of volatile organic compounds (VOCs) emitted from cattle manure.

The ability of biochar to be used as filter or as additive for the adsorption of volatile organic compounds (VOCs) emitted from cattle manure is investigated. The employed biochar was produced from cattle manure after slow pyrolysis at 550 °C (under nitrogen). Towards this, in-house-made glass emission reactors were filled with fresh cattle manure samples and a thin layer of biochar (10% w/w) was placed on the top of the manure layer. The mixture was left for 24 h to equilibrate and air samples were collected from the headspace air. The samples were then analyzed using the headspace solid-phase micro-extraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) method. Cattle manure emissions are considered unpleasant and odoriferous. The respective changes in the emitted cattle manure VOCs were reported; these included mainly reduction in sulfur- (thiols and sulfides) and oxygen-containing VOCs (alcohols, ketones, phenolics), showing a promising application of biochar for the removal of such compounds from manure wastes. Also, five VOCs were selected as sorbents for further laboratory studies: hexane, dimethyl trisulfide, phenol, p-cresol, and 2-methyl-3-pentanone. The results of cattle manure-derived biochar, revealed a reduction in their emitted concentrations (low ppbv). The present application highlights a straightforward example of cyclic economy, where a waste product is reused after being processed; its re-usage as odor adsorbent serves again the agriculture sector.

Volatile organic compounds in head and neck squamous cell carcinoma-An in vitro pilot study.

Owing to the lack of specific symptoms, diagnosis of head and neck squamous cell carcinoma (HNSCC) may be delayed. We evaluated volatile organic compounds in tumor samples from patients suffering from HNSCC and tested the hypothesis that there is a characteristic altered composition in the headspace of HNSCC compared with control samples from the same patient with normal squamous epithelium. These results provide the basis for future noninvasive breath analysis in HNSCC. Headspace air of suspected tumor and contralateral control samples in 20 patients were analyzed using ion-mobility spectrometry. Squamous cell carcinoma was diagnosed in 16 patients. In total, we observed 93 different signals in headspace measurements. Squamous cell carcinomas revealed significantly higher levels of volatile cyclohexanol (0.54 ppbv , 25th to 75th percentiles 0.35-0.86) compared with healthy squamous epithelium (0.24 ppbv , 25th to 75th percentiles 0.12-0.3; p < 0.001). In conclusion, head and neck squamous cell carcinoma emitted significantly higher levels of volatile cyclohexanol in headspace compared with normal squamous epithelium. These findings form the basis for future breath analysis for diagnosis, therapy control and the follow-up of HNSSC to improve therapy and aftercare.

Sensors’ array of aspiration ion mobility spectrometer as a tool for bacteria discrimination

The possibility of achieving bacterial discrimination using a miniaturized aspiration ion mobility spectrometer model ChemPro-100i (Environics Oy) has been tested by interrogating the headspace air samples above in vitro bacterial cultures of three species – Escherichia coli, Bacillus subtilis and Staphylococcus aureus, respectively. The ChemPro-100i highly integrated seven sensor array, composed of one a-IMS cell, three MOS (metal oxide sensors), one FET (field effect transistor) sensor and two SC (semiconductor) sensors, provided enough analytical information to discriminate between the three bacterial species. Statistical data processing using either principal component analysis (PCA) or partial least squares discriminant analysis (PLS-DA) was accomplished. We concluded that although the data from the aspiration-type ion mobility sensor, with its 16 ion detectors, is absolutely sufficient to discriminate between various bacteria using their volatile compounds’ chemical profile, the other six sensors deliver additional, valuable information.

Three-ways changed in headspace air on anaerobic fermentation

Different headspace condition has a great influence on fermentation process. In this study, whey protein was used as substrate, and the headspace air was changed in three different ways (H2 mixed N2, H2 mixed CO2, N2 with different sparging rates) to explore the effects of these three methods on products. The result showed that H2 mixed with CO2 is more conducive to acid production. Homoacetogenesis played a central role in fermentation process. There is a turning point in the role of hydrogen and Homoacetogenesis, which is when the partial pressure of hydrogen is 0.268 atm. In the first two conditions, the acid concentration increased with the increase of hydrogen percentage. Nitrogen sparging way is adverse to acid production, but conducive to gas production.

Methane production and nitrogen mineralization in paddy soil treated with sludge from anaerobic digestion enhanced by hyperthermophilic pretreatment

Hyperthermophilic pretreatment (80 °C, 24 h) is a technology that promotes methane yield in the anaerobic digestion of sewage sludge. However, little information is available on the characteristics of sludge anaerobically digested with hyperthermophilic pretreatment as a fertilizer and on the environmental impact of using the sludge as a fertilizer. In this study, we conducted incubation experiments to examine the characteristics of methane production and nitrogen mineralization in paddy soil treated with sludge from anaerobic digestion that was enhanced by hyperthermophilic pretreatment. Sludge samples digested under 15, 25, 30 and 35 °C with and without hyperthermophilic pretreatment were used. Sixty-mL vials were used in the experiment. Each vial was filled with 5 g of air-dried paddy soil, 10 mL of degassed water and digested sludge. It was then covered with a butyl rubber stopper, its headspace air was replaced by N2, and it was incubated at 30 °C. Methane concentrations in the headspace of the vials were measured after 7, 14, 28, 46, 57, 70 and 84 days. NH4-N concentrations in the soil were also measured after 0, 14, 28 and 84 days. The results indicated that relatively more methane tended to be produced in soil treated with sludge from anaerobic digestion that was enhanced by hyperthermophilic pretreatment than in non-pretreated sludge. On the other hand, a small amount of NH4-N was released from sludge digested with hyperthermophilic pretreatment at all digestion temperatures because organic nitrogen had been decomposed under hyperthermophilic pretreatment. Therefore, the appropriate application rate of sludge digested with hyperthermophilic pretreatment can be determined based on NH4-N in digested sludge without consideration of nitrogen mineralized after application when the sludge is used as a fertilizer.

GC-MS application in determination of volatile profiles emitted by infected and uninfected human tissue

Volatile organic compounds (VOCs) released into the headspace air over human tissues infected with different bacteria were investigated in this work. The above-mentioned VOCs result both from bacterial metabolic processes (pathogen-specific signals) and from the matrix (tissue samples themselves). The objective of this study was to investigate whether one could reliably identify various microorganism strains that exist inside infected tissue samples by direct monitoring of the headspace atmosphere above their cultures. Headspace samples were directly interrogated using a GC-MS system, which produced distinct profiles for samples contaminated with single bacterial strains or with multiple strains (mixed infections). Principal component analysis (PCA) and predictive analysis based on receiver operating characteristics curves (ROC) were the statistical procedures utilized for differentiating between infected and uninfected samples, while network analysis and heat-mapping were used to highlight the connections between emitted volatiles and infectious pathogens. By using ROC curves, obtained results demonstrated that the area under the ROC (95% probability interval) was 0.86 in case of infected samples and 0.48 for uninfected samples. On the other hand, PCA highlighted separation between components coming from infected and uninfected patients, where 67% of variance was described from the first 2 principal components. The biomarker chemicals documented from this work, as well as the developed methodology may ultimately be applied to identify bacterial infections by analyzing exhaled breath.

Improved in vivo measurement of alternative oxidase respiration in field-collected pine roots.

Cellular respiration via the alternative oxidase pathway (AOP) leads to a considerable loss in efficiency. Compared to the cytochrome pathway (COP), AOP produces 0-50% as much ATP per carbon (C) respired. Relative partitioning between the pathways can be measured in vivo based on their differing isotopic discriminations against 18 O in O2 . Starting from published methods, we have refined and tested a new protocol to improve measurement precision and efficiency. The refinements detect an effect of tissue water content (P < 0.0001), which we have removed, and yield precise discrimination endpoints in the presence of pathway-specific respiratory inhibitors [CN- and salicylhydroxamic acid (SHAM)], which improves estimates of AOP/COP partitioning. Fresh roots of Pinus sylvestris were sealed in vials with a CO2 trap. The air was replaced to ensure identical starting conditions. Headspace air was repeatedly sampled and isotopically analyzed using isotope-ratio mass spectrometry. The method allows high-precision measurement of the discrimination against 18 O in O2 because of repeated measurements of the same incubation vial. COP and AOP respiration discriminated against 18 O by 15.1 ± 0.3‰ and 23.8 ± 0.4‰, respectively. AOP contributed to root respiration by 23 ± 0.2% of the total in an unfertilized stand. In a second, nitrogen-fertilized, stand AOP contribution was only 14 ± 0.2% of the total. These results suggest the improved method can be used to assess the relative importance of COP and AOP activities in ecosystems, potentially yielding information on the role of each pathway for the carbon use efficiency of organisms.

Sedative effects of the essential oil and headspace air of Ocimum basilicum by inhalation in mice.

The sedative effects of the essential oil released by living Ocimum basilicum (basil) plants were investigated using a mouse activity monitoring system. Ocimum basilicum plants were grown in a hydroponic chamber, and either the headspace air from the hydroponic chamber or the essential oil extracted from mature plants was administered by the inhalation route to mice in an open field test. The most effective dose of O. basilicum essential oil for reducing the locomotor activity of the mice was found to be 4.0 × 10-3mg per cage. The headspace air was administered to mice held in a glass cage via a Teflon tube connected to a hydroponic chamber containing O. basilicum plants. A significant decrease in locomotor activity was observed when the hydroponic chamber contained nine plants. The results of this study demonstrate that the headspace air of living basil plants could effectively reduce the locomotor activity of mice.

Technical note: A simple and cost-efficient automated floating chamber for continuous measurements of carbon dioxide gas flux on lakes

Abstract. Freshwaters emit significant amounts of CO2 on a global scale. However, emissions remain poorly constrained from the diverse range of aquatic systems. The drivers and regulators of CO2 gas flux from standing waters require further investigation to improve knowledge on both global-scale estimates and system-scale carbon balances. Often, lake–atmosphere gas fluxes are estimated from empirical models of gas transfer velocity and air–water concentration gradient. Direct quantification of the gas flux circumvents the uncertainty associated with the use of empirical models from contrasting systems. Existing methods to measure CO2 gas flux are often expensive (e.g. eddy covariance) or require a high workload in order to overcome the limitations of single point measurements using floating chambers. We added a small air pump, a timer and an exterior tube to ventilate the floating chamber headspace and passively regulate excess air pressure. By automating evacuation of the chamber headspace, continuous measurements of lake CO2 gas flux can be obtained with minimal effort. We present the chamber modifications and an example of operation from a small forest lake. The modified floating chamber performed well in the field and enabled continuous measurements of CO2 gas flux with 40 min intervals. Combining the direct measurements of gas flux with measurements of air and waterside CO2 partial pressure also enabled calculation of gas exchange velocity. Building and using the floating chamber is straightforward. However, because an air pump is used to restart measurements by thinning the chamber headspace with atmospheric air, the duration of the air pump pause–pulse cycle is critical and should be adjusted depending on system characteristics. This may result in shorter deployment duration, but this restriction can be circumvented by providing a stronger power source. The simple design makes modifications of the chamber dimensions and technical additions for particular applications and systems easy. This should make this approach to measuring gas flux flexible and appropriate in a wide range of different systems.

A high throughput method for measuring cloth-air equilibrium distribution ratios for SVOCs present in indoor environments

Accumulation of chemicals from the environment to clothing and other textiles can influence human uptake by several exposure routes. In this research, we demonstrate that the cloth-air equilibrium distribution ratio for species i, KCA_i, can be measured relatively easily and quickly using headspace analysis of cloth dosed with two common indoor air SVOCs, diethyl phthalate (DEP) and di-n-butyl phthalate (DnBP). A known mass of a phthalate was applied to the cloth in a volatile solvent carrier. After evaporation of the solvent, the cloth was placed in a vial and allowed to equilibrate with the air in the vial. Since the volume of headspace air is small, the total mass required to transfer from cloth to air is small and also the time required for air equilibration with the fabric surface is very short (minutes). Distribution ratios for the two phthalate esters sorbed to cotton jean material, reported as the concentration in the bulk cloth divided by the air concentration, were measured at 20, 25, 32, and 40 °C. The volume-normalized distribution ratio, Kvol [(μg/m3)/(μg/m3)], ranged from (0.75 ± 0.01)× 105 to (5.6 ± 0.2) × 105 for DEP and (5 ± 0.3)× 105 to (57 ± 1) × 105 for DnBP. Mass-normalized distribution ratio, Kmass [m3/g], ranged from (0.25 ± 0.01) to (1.8 ± 0.1) for DEP and (1.6 ± 0.1) to (18.5 ± 0.5) for DnBP. The cloth-air distribution ratios obtained from this study compare favorably with previously published results using other methods. Although equilibration with air in the headspace can be rapid, diffusion into the textile fibers is a slower equilibration process. Overall, this simple method has the potential to rapidly generate distribution ratios for a large number of chemical-textile pairs.

Simulation of Hydrogen Sulfide Emission from Deep-Pit Manure Storage During Agitation

Abstract. Human and animal exposure to hydrogen sulfide (H2S) in animal barns has long been a serious issue due to the acute and chronic toxicity of H2S. The H2S concentration in the room air of deep-pit swine barns is usually within hundreds of parts per billion by volume; however, it can sharply increase to hundreds and even thousands of parts per million (ppm) during manure agitation and pump-out. To explore the sudden release and concentration distribution of H2S, this study collected and analyzed samples from varying depths of a normal non-foaming barn and a foaming barn and then mathematically simulated the H2S concentrations and emissions in the pit headspace and room air for both barns during pit agitation. Simulations were conducted for six ventilation scenarios, or six different combinations of pit fan and wall fan ventilation rates. The simulation results suggested that pit ventilation was more effective than wall ventilation in decreasing H2S concentration in room air where pigs may be housed during agitation. A minimal pit ventilation rate of 40 cfm per pig was necessary to lower the peak concentration in room air to less than the permissible exposure limit of 20 ppm. The simulation results also indicated that gas bubble release during agitation accounted for the main part (81%) of H2S emission in the foaming barn, and expedited molecular diffusion contributed the main part (70.2%) of H2S emission in the non-foaming barn. The disturbed air-manure interface during agitation induced a pH decrease and therefore increased the apparent overall mass transfer coefficient of H2S, resulting in a substantially increased mass transfer rate and concentration. The immediately dangerous to life or health (IDLH) concentration of 100 ppm may be reached during pit agitation if pit fan ventilation is not fully provided, and the duration of the exceedance could be more than 30 min. The results provide empirical data for future simulation of spatial and temporal H2S distribution and are beneficial for developing methods to control H2S below hazardous levels so that the health and safety of workers can be better secured. Keywords: Agricultural safety, Deep-pit storage, Hydrogen sulfide concentration, Sulfide distribution, Swine manure.

Manipulating Aggregation Behavior of the Uncharged Peptide Carbetocin

Peptides are usually administered through subcutaneous injection. For low potency drugs, this may require high concentration formulations increasing the risk of peptide aggregation, especially for compounds without any intrinsic chargeable groups. Carbetocin was used as a model to study the behavior of uncharged peptides at high concentrations. Manipulation of the aggregation behavior of 70 mg/mL carbetocin was attempted by selecting excipients which interact with hydrophobic groups in carbetocin, and cover hydrophobic surfaces and interfaces. Peptide aggregation was induced by shaking stress and followed over time. Carbetocin solutions showed significant visible particle formation already after 4 h of shaking stress. This particle formation was not due to supersaturation or phase separation but suggested a nucleated aggregation process. None of the excipients prevented carbetocin aggregation, though altered aggregation behavior was observed, such as induction of fibril formation for most, but not all, charged excipients. Sodium dodecyl sulfate was found to accelerate peptide aggregation both below and above the critical micelle concentration in half-filled vials. However, in the absence of an air headspace, sodium dodecyl sulfate above the critical micelle concentration was capable of preventing shaking-induced carbetocin aggregation. Our study highlights the complexity in rational excipient selection to stabilize uncharged peptides at high concentration.

Immunogenicity of protein aggregates of a monoclonal antibody generated by forced shaking stress with siliconized and nonsiliconized syringes in BALB/c mice.

In this study, we aimed to investigate the immunogenicity of protein aggregates of monoclonal antibodies (mAbs), generated by forced shaking stress with siliconized and nonsiliconized syringes in a mouse model. Samples were filled in siliconized and nonsiliconized syringes with shaking and headspace air. Characterization studies were performed using high-performance size-exclusion chromatography, nanoparticle tracking analysis, flow cytometry, micro-flow imaging and resonant mass measurement. The samples (10 or 100μg) were subcutaneously injected into BALB/c mice for 21days, and the anti-drug antibody (ADA) concentrations were monitored. In samples shaken with siliconized syringes [SO (+)], large amounts of submicron and subvisible protein aggregates were formed by interactions with silicone oil droplets. The characteristics of protein aggregates differed between the mAb solution and shaken samples, which strongly indicates that silicone oil accelerates protein aggregation. When administered at low doses, the ADA concentration in all samples increased with repeated injections, and SO (+) induced the highest immunogenicity. However, when administered at high doses, ADA concentration decreased following prolonged repeated administration for tolerance. These results indicated that mAb protein aggregation induced immunogenicity in mice, and SO (+) induced higher immunogenicity than samples shaken with nonsiliconized syringe.

Fermentation for Disinfesting Fruit Waste From Drosophila Species (Diptera: Drosophilidae).

Economic losses in a range of fruit crops due to the Drosophila suzukii (Matsumura) have become severe. Removal and treatment of fruit waste, which may harbor D. suzukii, is a key step in preventing reinfestation of fruit production. Natural fermentation for disinfesting fruit wastes from D. suzukii was examined at ambient air temperatures of 12-20 °C. Soft and stone fruit wastes infested with eggs, larvae, and pupae of Drosophila melanogaster (Meigen) or D. suzukii were placed in sealed vessels containing fruit wastes, and samples were retrieved at intervals and tested for the emergence of adults. Mean temperatures of the fruit waste in the sealed vessels during fermentation were 15-23 °C. Fermentation for 3 d was effective in disinfesting waste from different life stages of D. suzukii. Treatment for 4 d also ensured that the waste was free of viable life stages of D. melanogaster, which could be used as an indicator species for disinfestation of waste from D. suzukii owing to its greater tolerance of fermentation. The O2 concentration of the headspace air in the vessels became undetectable after 13-16 h, with a corresponding increase in CO2 concentration, which exceeded 80% vol/vol. The resulting hypoxia and hypercapnia may explain the efficacy of the fermentation treatment in disinfesting the waste. Fermented fruit remained attractive to D. suzukii and retained its capacity to rear a life cycle. Covering or mixing fermented fruit with a sufficient depth (0.1 m) or volume (×9) of soil or coir prevented the reinfestation of treated waste.

Temporal Nitrous Oxide Emissions from Beef Cattle Feedlot Manure after a Simulated Rainfall Event.

Nitrous oxide (NO) is a greenhouse gas (GHG) emitted from agricultural operations. The objective of this research was to quantify NO-N emissions from simulated open-lot beef cattle feedlot pens after rainfall. A recirculating-flow-through, non-steady state chamber system consisting of five 1-m steel pans was designed for quantifying emissions. A lid was placed sequentially on each pan, and headspace air was recirculated between the pan and a real-time NO analyzer, measuring concentrations every 1 s. Air-dried manure (89.2% dry matter) from a commercial feedlot in the Texas Panhandle was placed in the pans and then 0, 6.3, 12.7, 25.4, or 50.8 mm of water was applied to simulate a one-time rainfall event. Emissions of NO-N were monitored for 45 d, where two distinct episodes of NO-N production were observed over time. The first NO-N episode had a duration of 10 h and peaked 2 h after rainfall at a flux of 1.0 to 200 mg m h. The second episode had a duration of 40 d and peaked 15 d after rainfall at a flux of 0.06 to 35 mg m h. The second episode accounted for 69 to 91% of the cumulative NO-N emitted over the 45-d period. Each millimeter of rainfall increased cumulative NO-N emitted by 167.9 mg m ( = 0.99, < 0.001). This rainfall vs. cumulative emissions relationship will be useful for modeling annual NO-N emissions from open-lot beef cattle feedlots, and for assessing the effectiveness of best management practices for reducing feedlot GHG emissions.

Abstract 204: In vitro metabolomics of mesothelioma: Challenges and outcomes

Abstract Introduction Early detection of malignant pleural mesothelioma (MPM) is likely to improve outcome in affected patients. From our previous studies (MesoBreath 1 &amp; 2) we developed a screening tool in which volatile organic compounds (VOCs) in breath allowed discrimination of MPM patients from at risk controls. However it is not yet clear which VOCs arise from the neoplastic cells themselves or from the host response. Identifying the cancer cell-specific compounds should increase the specificity of our breathomic signature model. Therefore, we set up an in vitro experimental setup model for VOC analysis from the headspace of mesothelioma cell lines. Methods Standard polystyrene culture flasks (NunclonTM Delta Surface, Thermo Scientific) were mounted with an adapted cap accommodating teflon inlet and outlet tubes. The inlet tube provides environmental air while an external pump (Gilian GilAir Plus, Sensidyne) draws headspace air from the outlet tube over an adsorption column (Tenax GR, Markes International, UK). The adsorption columns were further processed on a GC-MS platform (GC: Focus GC, Thermo Finnigan, Milan, Italy; DSQII Single Quadrupole MS, Thermo Finnigan, Austin, TX, USA). VOC profiles were processed using supervised clustering algorithms and principal component analysis. Results Using this setup, we have investigated the impact of flow and total sampled volume on the concentration and range of VOCs detected. For a constant flow, VOCs were detected in higher concentrations with increasing sample volume. For a constant volume, a lower sampling flow yielded a higher concentration of detected VOCs. Most of the VOCs obtained were alkanes and ketones. We will show data illustrating the differential VOC profiles of container plastic, cell culture medium and growing mesothelioma cancer cells, as well as the differential VOC output of epithelioid vs sarcomatoid mesothelioma cell lines. Conclusions We have succesfully developed an in vitro experimental setup allowing collection and analysis of VOCs emanating from mesothelioma cancer cell line cultures. This platform will allow us to investigate how VOC profiles are impacted in different experimental conditions (e.g. hypoxia, nutrient deprivation, cytostatics, co-culture with leukocytes). The data collected will help us to pinpoint the cancer cell-derived VOCs from patient exhaled breath, and increase the robustness of our mesothelioma breathomic signature. Note: This abstract was not presented at the meeting. Citation Format: Sabrina Lagniau, Kevin Lamote, Lore Vandermeersch, Herman Van Langenhove, Jan P. van Meerbeeck, Karim Y. Vermaelen. In vitro metabolomics of mesothelioma: Challenges and outcomes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 204. doi:10.1158/1538-7445.AM2017-204