Low Volatile Compounds Research Articles

Improving coating and prepressing performance of soy protein-based adhesive by constructing a dual-bionic topological structure

Developing efficient and sustainable green adhesives to replace aldehyde-based adhesives has become an important strategy to address fossil resources depletion, environmental pollution, and clean production. Soy protein is a raw material-rich, renewable biomass material that can be used to prepare environmental-friendly adhesives. However, the weak interfacial adhesion of soy protein-based (SP) adhesives leads to poor coating and prepressing properties, thus limiting the large-scale application of the SP adhesives. In this study, a bionic "bond-stitch" molecular topology was designed and constructed in SP matrix to prepare a strong multifunctional adhesive. Inspiring by the strong adhesion of mussel, urushiol (U) with natural catechol structure and acrylamide were polymerized in situ into poly(urushiol-co-acrylamide) (PUAM) as stitching polymer, which was entangled with the SP network to form a bond-stitch molecular topology. The hydroxyapatite was used to construct an organic-inorganic hybridization in the SP matrix mimicking the tough cohesion of oysters. The resultant dual-bionic SP adhesive exhibited excellent coating performance, prepressing intensity (0.45 MPa), flame retardancy (the limiting oxygen index was 39.4%), mildew resistance (10 d), low volatile organic compounds release, and good antibacterial activity (the antibacterial rates against Escherichia coli, Staphylococcus aureus, and Candida albicans were 89.55%, 78.59%, and 99.91%, respectively.). The wet shear strength of the prepared SP adhesive was increased from 0.35 MPa to 1.17 MPa. This study provides a new strategy for the design and preparation of high-performance, sustainable, low-carbon footprint bio-adhesives and composites.

Origins of volatile compounds and identification of odour-active compounds in air-classified fractions of faba bean (Vicia faba L. minor)

Faba bean (Vicia faba L. minor) has many interests but is characterised by off-notes (negative odours/aromas) due to volatile compounds that are promoted during seed processing. Little is known about the volatile compounds of faba bean and their contribution to its odour. The purpose of this study was to determine the volatile compound origins of air-classified fractions (flour (F), starch (S) and protein (P)) from 3 faba bean cultivars and identify the odour-active compounds. Firstly, the volatile content of the fractions was extracted by solvent-assisted flavour evaporation (SAFE) and analysed by gas chromatography-mass spectrometry (GC–MS). A total of 147 volatile compounds were detected and categorised into 12 chemical classes. The P fractions had many volatile compounds from free fatty acid (FFA) oxidation and a higher lipoxygenase (LOX) activity. The volatile content suggested that cultivar 1 (C1) was confronted with a biotic stress at field whereas cultivar 2 (C2), richer in molecules from amino acid (AA) degradation, was contaminated by microorganisms in the field. Secondly, 35 odour-active compounds (OACs) were identified by GC-olfactometry (GC-O) and 12 odour-classes were used to describe the faba bean odours. The P fractions had higher detection frequency (DF) than the S and F fractions. P2 had a more complex odour profile due to important FFA and AA degradation. This work provides a better understanding of the impact of cultivar and processing steps on the faba bean volatile content. Selection of pulse-based ingredients with low volatile compounds could improve their flavour and increase their consumption.

Preparation of Low Volatile Organic Compounds Silver Paste Containing Ternary Conductive Fillers and Optimization of Their Performances.

Conductive silver paste is a key material in the fields of printed circuits and printed electronic devices. However, the preparation of conductive silver paste with low-cost and volatile organic compounds (VOCs) is still a challenge. In this work, conductive silver pastes with excellent comprehensive performances were developed by using water-borne polyurethane (WPU) as the bonding phase and using the ternary mixture of Ag microflakes (Ag MFs), Ag nanowires (Ag NWs), and Ag nanoparticles (Ag NPs) as the conductive phase. WPU endowed conductive silver pastes with the adhesion along with releasing a few VOCs during the curing. Results showed that a small amount of Ag NPs or Ag NWs dramatically enhanced the electrical conductivity of silver paste paint film filled only with Ag MFs. The electrical resistivity for optimal ternary mixture conductive silver paste was 0.2 × 10-3 Ω∙cm, and the conductive phase was composed of 20.0 wt% Ag MFs, 7.5 wt% Ag NWs, and 2.5 wt% Ag NPs. Meanwhile, the adhesive strength and hardness of silver paste paint film were effectively improved by increasing the curing temperature. The optimal overall performance of the conductive silver pastes was achieved at the curing temperature of 160 °C. Therefore, this work can provide a new route for preparing conductive silver pastes with high performances.

Isoprene Epoxydiol-Derived Sulfated and Nonsulfated Oligomers Suppress Particulate Mass Loss during Oxidative Aging of Secondary Organic Aerosol.

Acid-driven multiphase chemistry of isoprene epoxydiols (IEPOX) with inorganic sulfate aerosols contributes substantially to secondary organic aerosol (SOA) formation, which constitutes a large mass fraction of atmospheric fine particulate matter (PM2.5). However, the atmospheric chemical sinks of freshly generated IEPOX-SOA particles remain unclear. We examined the role of heterogeneous oxidation of freshly generated IEPOX-SOA particles by gas-phase hydroxyl radical (•OH) under dark conditions as one potential atmospheric sink. After 4 h of gas-phase •OH exposure (∼3 × 108 molecules cm-3), chemical changes in smog chamber-generated IEPOX-SOA particles were assessed by hydrophilic interaction liquid chromatography coupled with electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (HILIC/ESI-HR-QTOFMS). A comparison of the molecular-level compositional changes in IEPOX-SOA particles during aging with or without •OH revealed that decomposition of oligomers by heterogeneous •OH oxidation acts as a sink for •OH and maintains a reservoir of low-volatility compounds, including monomeric sulfate esters and oligomer fragments. We propose tentative structures and formation mechanisms for previously uncharacterized SOA constituents in PM2.5. Our results suggest that this •OH-driven renewal of low-volatility products may extend the atmospheric lifetimes of particle-phase IEPOX-SOA by slowing the production of low-molecular weight, high-volatility organic fragments and likely contributes to the large quantities of 2-methyltetrols and methyltetrol sulfates reported in PM2.5.

Influences of different surface oxygen species on oxidation of toluene and/or benzene and their reaction pathways over Cu-Mn metal oxides

Catalytic oxidation is considered as the most effective and economical method to remove low concentration volatile organic compounds (VOCs). Activation of oxygen to form active oxygen species on metal oxides catalyst plays a key role in the process. Three copper-manganese oxide catalysts with cubic Cu1.5Mn1.5O4 phases were prepared by microwave heating (CM-MW), sol–gel (CM-SG) and co-precipitation (CM-CP) methods, and applied for the elimination of toluene and benzene as representative aromatic VOCs. These catalysts exhibit different catalytic oxidation performance due to their different physicochemical properties. Various characterizations were used to clarify the role of different oxygen species in the oxidation of VOCs, and the reaction pathway. In situ DRIFTS were carried out to explore the function of surface adsorbed oxygen, oxygen vacancy, and surface lattice oxygen in the catalytic oxidation of VOCs over three catalysts. Various types of intermediate species and detailed reaction pathways are also explored by combining in situ DRIFTS and mass spectrometry. Among these catalysts, CM-MW with nanosheet morphology shows the best catalytic oxidation performance of toluene and/or benzene with/without H2O due to the most abundant active oxygen species, and the highest oxygen vacancy concentration which is beneficial to activate oxygen. Meanwhile, toluene and benzene do not interfere with each other during the mixture oxidation. This study can provide new inspiration for rational design of metal oxide catalysts to remove VOCs.

Gas Chromatography—High-Temperature Proton-Transfer Reaction Mass Spectrometry as a Novel Tool for Forensic Drug Testing

Proton-transfer reaction mass spectrometry (PTR-MS) is a versatile tool for the mass spectrometric analysis of organic molecules in gaseous samples. Due to its operation principle, PTR-MS is a soft ionization technique generating spectral data typically rich in protonated molecule information. Most of the currently reported PTR-MS applications are designed to determine volatile compounds. Herein, we present a redesigned instrumental setup termed “high-temperature (HT)-PTR-MS” with improved capabilities for the analysis of low-volatile compounds. The developed HT-PTR-MS prototype was successfully hyphenated with gas chromatography (GC) to enable qualitative and quantitative analysis of licit and illicit drugs in human blood/plasma samples. Different kinds of spiked and authentic samples were used to evaluate the performance of the GC-HT-PTR-MS in forensic drug testing. Benchmarking against GC-MS with electron ionization demonstrated the improved detection capabilities of GC-HT-PTR-MS in screening applications. On average, one order of magnitude lower limits of detection/identification were reached. Clearly, GC-HT-PTR-MS has the vast potential to complement or even replace established mass spectrometric techniques in forensic drug analysis.

Mn-Co bimetallic spinel catalyst towards activation of peroxymonosulfate for deep mineralization of toluene: The key roles of SO4•- and O2•- in the ring-opening and mineralization of toluene

Developing novel method that can deeply mineralize low concentration volatile organic compounds (VOCs) under ambient temperature is still a challenge. This study fabricates a nonstoichiometric Mn-Co bimetallic spinel catalyst, MnCo2O4.5, which exhibits excellent activity towards peroxymonosulfate (PMS) activation and superior to other similar advanced oxidation processes (AOPs) in mineralization of toluene. The crystalline phase, microstructure and composition of the catalyst were revealed by a series of characterization methods. The MnCo2O4.5/PMS system can stably remove 97.3 % of toluene over 25 h with less PMS dosage, and the CO2 selectivity reaches 85.3 %, its CO2 yield is 2.8 and 6.4 times as many as those of Co3O4 and MnO. MnCo2O4.5 also exhibits a good pH adaptivity (pH = 3–7) and highly chemical stable in acidic conditions, with low metals leaching rate and excellent reusability. Electron paramagnetic resonance (EPR) and radical quenching tests reveal the radicals’ contributions to the conversion and mineralization of toluene, i.e. SO4•- > O2•- > HO• >1O2 and O2•- >1O2 > HO• > SO4•-, respectively. Combined the gas chromatography-mass spectrometry (GC–MS) analyses and quantum chemical calculation, the toluene degradation routes induced by HO• and SO4•- were detailedly summarized. This novel mild method provides a new thought on the development of low-temperature VOCs control technologies.

The influence of the addition of isoprene on the volatility of particles formed from the photo-oxidation of anthropogenic–biogenic mixtures

Abstract. In this study, we investigate the influence of isoprene on the volatility of secondary organic aerosol (SOA) formed during the photo-oxidation of mixtures of anthropogenic and biogenic precursors. The SOA particle volatility was quantified using two independent experimental techniques (using a thermal denuder and the Filter Inlet for Gas and Aerosols iodide high-resolution time-of-flight Chemical Ionisation Mass Spectrometer – FIGAERO-CIMS) in mixtures of α-pinene/isoprene, o-cresol/isoprene, and α-pinene/o-cresol/isoprene. Single-precursor experiments at various initial concentrations and results from previous α-pinene/o-cresol experiments were used as a reference. The oxidation of isoprene did not result in the formation of detectable SOA particle mass in single-precursor experiments. However, isoprene-derived products were identified in the mixed systems, likely due to the increase in the total absorptive mass. The addition of isoprene resulted in mixture-dependent influence on the SOA particle volatility. Isoprene made no major change to the volatility of α-pinene SOA particles, though changes in the SOA particle composition were observed and the volatility was reasonably predicted based on the additivity. Isoprene addition increased o-cresol SOA particle volatility by ∼5/15 % of the total mass/signal, respectively, indicating a potential to increase the overall volatility that cannot be predicted based on the additivity. The addition of isoprene to the α-pinene/o-cresol system (i.e. α-pinene/o-cresol/isoprene) resulted in slightly fewer volatile particles than those measured in the α-pinene/o-cresol systems. The measured volatility in the α-pinene/o-cresol/isoprene system had an ∼6 % higher low volatile organic compound (LVOC) mass/signal compared to that predicted assuming additivity with a correspondingly lower semi-volatile organic compound (SVOC) fraction. This suggests that any effects that could increase the SOA volatility from the addition of isoprene are likely outweighed by the formation of lower-volatility compounds in more complex anthropogenic–biogenic precursor mixtures. Detailed chemical composition measurements support the measured volatility distribution changes and showed an abundance of unique-to-the-mixture products appearing in all the mixed systems accounting for around 30 %–40 % of the total particle-phase signal. Our results demonstrate that the SOA particle volatility and its prediction can be affected by the interactions of the oxidized products in mixed-precursor systems, and further mechanistic understanding is required to improve their representation in chemical transport models.

Heat Pulse Desorption of Low-Volatility Compounds by a Heated N2 Gas Pulse with Mass Spectrometry.

For the thermal desorption of low-volatility compounds, rapid heating followed by instant cooling is desirable to suppress thermal decomposition. In this work, a new thermal desorption method, heat pulse desorption (HPD), was developed. A heated N2 gas pulse (350 °C, 50 ms) was directed to the solid sample surface, and desorbed analytes were ionized by DC corona discharge and mass analyzed by an Orbitrap mass spectrometer. Because heat transfer from the heated N2 gas to the solid surface is not very efficient, desorption of the solid sample occurs at a certain temperature before reaching 350 °C. In short, there is a self-controlling desorption depending on the volatility of each analyte. Because the exit of the copper tube for gas blowing is separated from the sample surface, no carryover occurs, enabling the repetitive analysis of samples. HPD was applied to various compounds such as narcotics, pharmaceutical tablets, and explosives. Because analysis is completed within a few seconds per sample, this method is highly useful for quick and consecutive analysis of real samples, having potential utility in food quality control, counterfeit drugs analysis, and the detection of explosives for safety and security.

Light absorption potential of water-soluble organic aerosols in the two polluted urban locations in the central Indo-Gangetic Plain

PM2.5 (particulate matter having aerodynamic diameter ≤2.5 μm) samples were collected during wintertime from two polluted urban sites (Allahabad and Kanpur) in the central Indo-Gangetic Plain (IGP) to comprehend the sources and atmospheric transformations of light-absorbing water-soluble organic aerosol (WSOA). The aqueous extract of each filter was atomized and analyzed in a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). Water-soluble organic carbon (WSOC) and WSOA concentrations at Kanpur were ∼1.2 and ∼1.5 times higher than that at Allahabad. The fractions of WSOC and secondary organic carbon (SOC) to total organic carbon (OC) were also significantly higher ∼53% and 38%, respectively at Kanpur compared to Allahabad. This indicates a higher abundance of oxidized WSOA at Kanpur. The absorption coefficient (babs-365) of light-absorbing WSOA measured at 365 nm was 46.5 ± 15.5 Mm−1 and 73.2 ± 21.6 Mm−1 in Allahabad and Kanpur, respectively, indicating the dominance of more light-absorbing fractions in WSOC at Kanpur. The absorption properties such as mass absorption efficiency (MAE365) and imaginary component of refractive index (kabs-365) at 365 nm at Kanpur were also comparatively higher than Allahabad. The absorption forcing efficiency (Abs SFE; indicates warming effect) of WSOA at Kanpur was ∼1.4 times higher than Allahabad. Enhancement in light absorption capacity was observed with the increase in f44/f43 (fraction of m/z 44 (f44) to 43 (f43) in organic mass spectra) and O/C (oxygen to carbon) ratio of WSOA at Kanpur while no such trend was observed for the Allahabad site. Moreover, the correlation between carbon fractions and light absorption properties suggested the influence of low-volatile organic compounds (OC3 + OC4 fraction obtained from thermal/optical carbon analyzer) in increasing the light absorption capacity of WSOA in Kanpur.

Environmentally-friendly short-chain perfluoropolyether polyacrylates emulsion films for high water barrier coating applications

Water-based protective coatings have gained wide popularity because of their low toxicity and volatile organic compounds (VOCs) emissions. However, improving water barrier performance is a significant challenge. An environmentally friendly short-chain perfluoropolyether carboxylic acid (PFPE-MMA) material has been synthesized in this study, and a series of PFPE-based polyacrylates were prepared using RAFT miniemulsion copolymerization. The impact of PFPE chains and crystalline stearyl methacrylate (SMA) on the wettability of copolymer latex films and their use in protective coatings were studied. Based on the surface and bulk morphology of latex films, the addition of SMA to PFPE-based polyacrylates promoted PFPE chains to migrate toward the air/film interface, leading to exceptional wettability and water resistance through the matrix, resulting in remarkable water barrier properties. After 192 h, the water absorption ratio of 25% PFPE-7% SMA latex film was 3.98%, while that of 25% PFPE latex film was 6.03%. Not only are PFPE-based polyacrylates excellent protective materials with potential applications, but they are also an effective preparation strategy for improving the high barrier property in waterborne protective coatings.

Quantitative Analysis of Exhaled Breath Collected on Filter Substrates via Low-Temperature Plasma Desorption/Ionization Mass Spectrometry.

Breath analysis has attracted increasing attention in recent years due to its great potential for disease diagnostics at early stages and for clinical drug monitoring. There are several recent examples of successful development of real-time, in vivo quantitative analysis of exhaled breath metabolites via mass spectrometry. On the other hand, current mass spectrometer accessibility limitations restrict point-of-care applications. Here now, an offline method is developed for quantitative analysis of exhaled breath collected on inexpensive filter substrates for direct desorption and ionization by using low-temperature plasma-mass spectrometry (LTP-MS). In particular, different operating conditions of the ionization source were systematically studied to optimize desorption/ionization by using glycerol, a low volatility compound. Applications with respect to propofol, γ-valprolactone, and nicotine analysis in exhaled breath are demonstrated in this study. The effects of several filter substrate properties, including filter material and pore size, on the analyte signal were characterized. Cellulose filter papers performed best with the present analytes. In addition, filters with smaller pores enabled a more efficient sample collection. Furthermore, sample-collection flow rate was determined to have a very significant effect, with slower flow rates yielding the best results. It was also found that filters loaded with sample can be successfully stored in glass vials with no observable sample loss even after 3 days. Limits of detection under optimized conditions are shown to be competitive or significantly better compared with relevant techniques and with additional benefits of cost-efficiency and sample storage capabilities.

Influence of emission size distribution and nucleation on number concentrations over Greater Paris

Abstract. With the growing evidence that high particle number concentrations may impact health, modelling their emissions and understanding formation processes is necessary, especially in cities where many people are exposed. As emission inventories of particle numbers and size distribution over cities are usually not available, a methodology is defined to estimate them from PM2.5 emissions and ratios of PM1 / PM2.5 and PM0.1 / PM2.5 by activity sector. In this methodology, a fitting parameter αem is used to redistribute the number concentrations in the lowest emission diameter range. This parameter is chosen by comparing measured and simulated number concentrations during non-nucleation days. The emission size distribution is then finely discretised by conserving both mass and number in each of the size ranges where emissions are specified. The methodology is applied over Greater Paris during the MEGAPOLI campaign (July 2009). Three-dimensional simulations are performed using the chemistry transport model Polair3D/Polyphemus coupled to the aerosol module SSH-aerosol to represent the evolution of particles by condensation, evaporation, coagulation, and nucleation, with a sectional approach for the size distribution. The model is first compared to measurements during non-nucleation days, and the influence over the month of July 2009 of three different nucleation parameterisations is assessed, i.e. binary (sulfuric acid, water), ternary (sulfuric acid, ammonia, water), and heteromolecular (extremely low-volatility organic compounds (ELVOCs) from monoterpenes and sulfuric acid). The modelled number concentrations compare very well to measurements, with an average normalised mean error of 42 % for the daily number concentrations of particles larger than 10 nm and 37 % for the number concentrations of particles larger than 100 nm. The influence of the binary nucleation is low, and the ternary nucleation scheme leads to better simulated number concentrations (in terms of bias and error) at only one site out of three, but it systematically reduces the model to measurement correlation, suggesting that ternary nucleation may not be the dominant process in new particle formation. However, the relative bias and error, as well as the correlation at suburban sites, are systematically improved using the heteromolecular nucleation scheme involving sulfuric acid and ELVOCs from monoterpenes. This suggests that heteromolecular nucleation may be important in cities, especially at suburban sites in summer, and that a better characterisation of the emissions of ELVOC precursors from traffic is needed.

Formation of extremely low-volatility organic compounds from styrene ozonolysis: Implication for nucleation

Styrene is a highly reactive compound with the dual nature of aromatics and olefins. This work presents evidence for formation of extremely low-volatility organic compounds (ELVOCs) from styrene ozonolysis. The molecules of ELVOCs were analyzed using a high-resolution orbitrap mass spectrometer. The results show that ELVOCs were oligomers characterized by stabilized Criegee radicals (SCIs) as chain units. The addition of C6H5CHOO (SCI1) or CH2OO (SCI2) can dramatically decrease the oligomers' volatility. At low relative humidity (RH), ELVOCs are mainly formed from the reaction of RO2 radical, C6H5OO·, with SCI1 and SCI2; however, ELVOCs are primarily produced by the reaction between benzoic acid and SCI1 at high RH. Ambient particles were also collected to propose the probable oligomers from styrene-SCI. Our results suggest that styrene-SCI derived ELVOCs may act as nucleating agents, potentially providing an experimental basis for nucleation events that frequently occur in urban areas.

Effect of NO2 on nocturnal chemistry of isoprene: Gaseous oxygenated products and secondary organic aerosol formation

As one of the most abundant non-methane hydrocarbon in the atmosphere, isoprene has attracted lots of attention on its oxidation processes and environmental effects. However, less is known about the nocturnal chemistry of isoprene with multiple oxidants coexisting in the atmosphere. Besides, though highly oxygenated molecules (HOMs) have recently been recognized to contribute to secondary organic aerosol (SOA) formation, the specific contribution of measured HOMs on SOA formation in isoprene oxidation has not been well established. In this study, the oxidation of isoprene was simulated under dark and various NO2/O3 conditions. Plenty of oxidation products were identified by combining two state-of-the-art time-of-flight mass spectrometers, and more species with high C and N numbers and low volatilities were detected under high NO2 conditions. The nocturnal oxidation of isoprene was found to be governed by synergic effects of multiple oxidants, including O3, NO3•, and •OH at the same time, and the oxidation proportions changed with NO2. NO2 promoted the formation of most N-containing products especially N2 products, because of the decisive role of NO3• on their formation. Nevertheless, some products such as C5H10O3–5, C5H11NO6, and C10H16N2O10,11 showed a better correlation with HO2NO2 rather than NO2/O3, indicating the importance of HO2• chemistry on the oxidation products formation. Though the concentration of measured oxygenated products was dominated by volatile and semi-volatile organic compounds, the low- and extremely low-volatile organic compounds contributed over 97 % to the SOA formation potential. However, challenges still exist in accurately simulating SOA formation from the measured oxygenated molecules to match the measurement, and further comprehensive characterization of oxidation products in both gas and aerosol phases at the molecular level is needed.

Influence of Zinc Coatings Mechanical Pre-Treatments for the Formation of Environmentally Friendly Passivation Duplex Anti-Corrosion Systems

Abstract The paper content is focused on the various evaluation methods of mechanical pre-treatment of hot-dip galvanized surface performed in order to increase the organic paint adhesion (both synthetic and waterborne). Emphasis was placed on low volatile organic compounds (VOC) values in coating systems. Corrosion degradation of the tested coatings was also monitored. The mechanical surface pre-treatment was performed using a standard technology, so-called sweeping, with synthetic corundum with F40 grain size (these samples served as a standard). Alternative methods that can be used in operations without blasting equipment were also investigated. These included regrinding with two different grain sandpapers (P40 and P100) and regrinding with a corrosion resistant steel brush (wire diameter 0.3 mm). The surface texture was evaluated in accordance with the ČSN EN ISO 4287 standard. Corrosion-mechanical resistance was evaluated by a pull-off adhesion test (according to the ČSN EN ISO 4624 standard) and in a salt spray environment (according to the ČSN EN ISO 9227 standard). Based on the obtained results, mechanical pre-treatment with a corrosion resistant steel brush and possibly P100 grit sandpaper can be recommended, as pre-treatment with these tools showed statistically the best corrosion-mechanical properties.

Simulation of the effects of low-volatility organic compounds on aerosol number concentrations in Europe, Atmos. Chem. Phys., 22, 1689–1706, 2022.

Simulation of the effects of low-volatility organic compounds on aerosol number concentrations in Europe, Atmos. Chem. Phys., 22, 1689–1706, 2022.

Brassinosteroids are involved in volatile compounds biosynthesis related to MdBZR1 in ‘Ruixue’ (Malus × domestica Borkh.) fruit

Aroma is a crucial quality attribute of apple fruit, mainly determined by volatile compounds. However, to our knowledge, the physiological and molecular roles of brassinosteroids (BRs) in volatile compound biosynthesis had not been elucidated. In this study, 24-epibrassinolide (EBR) inhibited fruit firmness and ethylene production and delayed fruit ripening. Total soluble solids, fructose content, glucose, and sucrose content were inhibited by EBR treatment. Most importantly, enzyme activity, volatile compound production, and genes involved in volatiles biosynthesis were suppressed compared with those in the control after EBR treatment. Furthermore, volatile compounds production and biosynthesis gene expressions was decreased by the overexpression of MdBZR1, whereas opposite results were observed when MdBZR1 was silenced. Notably, OE-MdBZR1 calli showed lower volatile compound content than that of the control calli by EBR treatment. Collectively, these results indicate that BR activate MdBZR1 expression, which in turn inhibited volatile compound production.

The gas phase retention volume behavior of organophosphate esters on polyurethane foam

In this study, the gas-phase retention volume behavior of four highly volatile organophosphate esters (OPEs) on polyurethane foam (PUF) was studied using a frontal chromatogram. The breakthrough volumes (VB) of trimethyl phosphate (TMP), triethyl phosphate (TEP), tripropyl phosphate (TPrP), and tri-n-butyl phosphate (TnBP) were 0.33, 0.59, 10.5, and 32.4 m3, respectively. A significant negative correlation was found between the logarithm value of VB and the subcooled liquid vapor pressure (PL) with an r2 of 0.905, indicating that the vapor penetration depends on both the volatility and total air volume. The enthalpy of desorption and vaporization (ΔHS−ΔHV) showed a significant difference between the tested OPEs and polycyclic aromatic hydrocarbons (PAHs), revealing that the strength of the sorption interaction of the tested OPEs vapor on PUF should be different from that of PAHs. The PUF-air partition coefficients (KPUF-air) of the tested OPEs ranged from 4.3 to 8.1, which were lower than those of three-to four-ring PAHs (7.02–10.2) and organochlorines (8.01–9.72), revealing that the partition of highly volatile OPEs on PUF is lower than that of low-volatile compounds. The PUF/XAD cartridge improved the absorption efficiency of the tested OPEs; however, its sorptive capacity was still limited.

3D printing: Economical and supply chain independent single-use plasticware for cell culture

3D printing represents a democratization of manufacturing processes, and inexpensive 3D printed parts for cell culture have been tested as replacements for single-use plastics currently unavailable due to worldwide supply chain issues. In addition, such distributed manufacturing of cell culture laboratory materials helps remote areas and developing countries with limited resources. HEK293 cells were used to test printed shake flasks for cell culture applications and their ease of manufacture. Recorded growth curves showed that renewable biodegradable poly(lactic acid) (PLA) thermoplastic is an excellent and economical replacement for single-use plastic shake flasks, which have shipment lead times during pandemic situations or other supply chain disruptions of over 6 months. With a price of 0.60 € in materials, and printing machines with prices lower than one box of single-use pre-sterilized plastic shake flasks (<350€), the use of PLA is very affordable. Low-cost photopolymerization resins were also tested, but the inherent cytotoxicity of these materials prevented cell growth. This was also true for plant-based resins marketed as having low volatile organic compounds (VOC). Treatment of parts to reduce VOC content was partially successful, but not sufficient to sustain prolonged cell growth. A high-cost medical device IIa-class material showed no improved cell growth. Nevertheless, with PLA a low-cost printing material was identified and the use as cell culture compatible material was demonstrated, providing low-cost supply chain independence. In the future, the printing of pilot-scale bioreactors with PLA as a green sustainable material at the point of its use will be possible.