Triethylamine Concentration Research Articles

The synergistic effect of La dopant/willow catkins template on SnO2 monotubes for efficient detection of triethylamine

The detection of volatile organic compounds (VOCs) such as triethylamine (TEA) is essential for maintaining air quality and human health. This study explores the synergistic effects of lanthanum (La) doping and the use of willow catkins as a template for the performance of SnO₂ gas sensors for TEA detection. The morphology and structure of the as-synthesized samples were investigated, and a series of experiments were conducted to explore the TEA sensing characterization of SnO2-based sensors. The results of gas sensing demonstrated that the response of La2-SnO₂ sensors is up to about 178 at 100 ppm TEA, showing a 45 % increase compared to pure SnO₂ with a detection limit as low as 5 ppb. The fabricated sensors demonstrated a rapid response time of 60 s and a recovery time of 98 s at 100 ppm TEA concentration. Moreover, the sensors showed stable and repeatable responses over multiple cycles, indicating excellent reproducibility and long-term stability. The enhanced TEA sensing performance can be attributed to the abundant oxygen vacancies and promising tubular structure, which not only offer more active sites to absorb oxygen species but also promote the adsorption-desorption process of gas molecules. This study highlights the potential of La-doped SnO₂ sensors fabricated using a sustainable willow catkins template as a promising candidate for practical TEA detection applications.

Dual-Functional Tungsten-Doped NiO for Highly Sensitive Triethylamine Sensor with ppb Level Detection Limit.

In this study, the W-doped Nickel oxide (NiO) nanoflowers were synthesized using a straightforward hydrothermal method, significantly enhancing the sensing performance toward triethylamine through dual-functional tungsten doping. The optimal doping concentration not only increased the specific surface area of NiO from 25.54 to 189.19 m2 g-1 but also reduced the formation energy of oxygen vacancies. The sensor containing 4 at % W-doped NiO demonstrated exceptional sensitivity to triethylamine, achieving a detection level as high as 229.0 for concentrations of 100 ppm at 237.5 °C. This triethylamine sensor represents a 135-fold enhancement over sensors fabricated from undoped NiO, and offers a rapid response/recovery time of 8 and 30 s, respectively. Furthermore, at a lower triethylamine concentration of 50 ppb, indicating a lower detection limit.

DPPM-Bridged Binuclear Pt(II) Pincer Complexes: Chemistry, Structure, and Photophysics in Solution Revisited.

A series of luminescent binuclear ([dppm{Pt(NNC)}2]2+) and mononuclear ([PPh3Pt(NNC)]+) complexes containing pincer ligands were synthesized and characterized. Photophysical characteristics of both types of complexes were studied in dichloromethane solution. In the solid phase, the binuclear compounds adopt a syn configuration where the {Pt(NNC)} fragments are held together due to intramolecular Pt-Pt bonding and π-stacking of the pincer ligand aromatic systems. Analysis of the complexes' molecular structure in solution by multinuclear NMR spectroscopy showed that the stacked intramolecular configuration is retained in fluid media, which is in complete agreement with a considerable red shift of the emission wavelength due to formation of the intramolecular Pt-Pt bond, leading to the transformation of an emissive excited state to 3MMLCT. It was also found that triethylamine quenches the emission of both types of complexes; the mechanism of quenching is a combination of dynamic and static channels of excited-state deactivation. In the case of binuclear complexes, deprotonation of the dppm methylene bridge by triethylamine also contributes to the chromophore quenching. To explain the observed chemistry of binuclear complex interactions with Et3N, a chemical equilibrium scheme was suggested, which was confirmed by quantitative monitoring of the 31P signal variations as a function of triethylamine concentration.

A high-efficiency photocatalytic hydrogen evolution system based on nickel-quinoxaline dithiolate complexes and water-soluble CdSe quantum dots

Photocatalytic water splitting of water for hydrogen evolution is one of the effective methods to obtain clean hydrogen energy. In the present work, the following materials were synthesized: two nickel quinoxaline thiolate complexes [NBu4]2 [Ni(qdt)2] (1, Bu = n-butyl, qdt = quinoxaline-dithiol), [NBu4]2 [Ni(qdt)2(NO2)2] (2) and water-soluble MPA-CdSe quantum dots (MPA-CdSe QDs, MPA = 3-mercaptopropionic acid). Subsequently, an efficient three-component photocatalytic hybrid system for hydrogen evolution was developed and tested under visible light irradiation, in which one of the target complex 1 or 2 was used as the catalyst, triethylamine (TEA) was used as the sacrificial electron donor, and MPA-CdSe QDs were used as the light harvesting reagent. The turnover numbers (TON) for H2 evolution of 8974 (vs. complex 1) and 6532 (vs. complex 2) were obtained under the optimal conditions with TEA concentration of 5 %, pH = 12, and concentration of complex 1 or 2 of 1 × 10−5 mol L−1 after 13 h of irradiation (λ > 420 nm) in pure water. The mechanism investigation indicated that critical steps of hydrogen production was formation of hydride intermediates Ni(II)-H and Ni(I)-H spices, followed by the reaction of two Ni(II)-H or Ni(I)-H species with protons generating H2 molecules and regenerating the catalyst Ni(II).

C3N4 modified PdO-Ru-functionalized ZnO long-grained nanoparticles for fast detection of ppb-level triethylamine

Triethylamine is a vital chemical raw material, but its leakage will pollute the environment and harm human health. It is particularly important to achieve detection of triethylamine. Here, PdRu nanoparticles, ZnO long-grained nanoparticles and C3N4 were prepared for the identification of low concentrations of triethylamine. The response value of the sensor based on PdO-Ru/ZnO-C3N41 to 20 ppm triethylamine was 96 at 220 °C. Furthermore, the lowest detection amount of it was as low as 50 ppb. And the time for rapid detection of 20 ppm triethylamine was shown to be 1 s. Besides, a circuit was designed to detect triethylamine in real time and raise the alarm when the concentration of triethylamine exceeded a threshold. The catalytic ability of PdRu nanoparticles and the formation of n-n heterojunction between ZnO and C3N4 were conducive to enhancing the sensing performance. This work provides a way for monitoring of triethylamine and timely warning in chemical plants.

MXene/In2S3 micro-nano composites for heighten the select specificity and rapid response to triethylamine

Molecular responsive materials with fast, stable, and specific selectivity are a key focus of chemical sensor technology research. In the field of triethylamine (TEA) sensor technology, developing TEA-selective responsive materials with superior performance is of great significance for promoting technological progress and industrialization of TEA sensor technology. In this study, MXene/In2S3 micro-nano powder was prepared by combining Ti3C2Tx-type MXene with nano-sized In2S3. The morphology, structure, and structure-performance relationship of the material were characterized and analyzed using SEM, TEM, XRD, HAADF, and XPS. Through experiments, it was confirmed that MXene/In2S3 exhibited outstanding specific selectivity to TEA. At a TEA concentration of 20 ppm and a temperature of 210 °C, the response value of the material to TEA was 8.74, while other typical gas molecules such as aldehydes, ketones, and aromatics showed almost no response, demonstrating excellent selectivity for TEA molecules. The response/recovery time was 19 s/42 s, and the response value was stable over 20 consecutive cycles, indicating excellent reliability of the material. In addition, in the concentration range of 1–500 ppm, the response value of the MXene/In2S3 material to TEA concentration followed an exponential fitting of the asymptotic model, with the formula y = a-b*cx and R2 of 0.99472. Furthermore, the selection and response process of MXene/In2S3 micro-nano materials and TEA molecules were analyzed from the molecular internal structure, and it was found that the selective response characteristics of the material to TEA were related to its microstructure, including shape adsorption.

Analytical method development supported by DoE-DS approach for enantioseparation of (S,S)- and (R,R)-moxifloxacin

In this paper, method for enantiomeric purity testing of fourth-generation fluoroquinolone, moxifloxacin hydrochloride, was developed and validated. Exceptional enantioselectivity for this assay was achieved using cyclodextrin type Chiral Stationary Phase (CSP), phenylcarbamate-β-cyclodextrin CSP, and mobile phase consisted of acetonitrile and triethylammonium acetate (TEAA) buffer. Analytical Quality by Design (AQbD) methodology, comprising Design of Experiments (DoE) - Design Space (DS) approach, was used for method development. In order to select appropriate Critical Method Parameters (CMPs), risk assessment was done using combined three step strategy that involved Ishikawa diagram - CNX (Control, Noise and eXperimental) - FMEA (Failure Mode and Effect Analysis). Three CMPs were further selected and investigated in this study: acetonitrile content in the mobile phase (30–50%, v/v), triethylamine content in the TEAA buffer (0.1–1.5%, v/v) and aqueous phase pH (3.5–4.5). Monte Carlo simulations were performed and 3D-DS was computed. One point situated in the center of 3D-DS was selected as working point for method validation, with the following values of CMPs: acetonitrile content in the mobile phase set to 37% (v/v), triethylamine content in TEAA 0.8% and pH value of the aqueous phase set at 4.0. Also, 2D-DS was created (with fixed one factor – pH value of aqueous phase at 4.0) which also gave us confirmation that the selection of working conditions was suitable. The proposed enantioselective method was further on tested for its quantitative robustness, as well as for its suitability for the intended purpose through validation studies.

Ppb-Level Detection Triethylamine Gas Sensor Based on Ag-Doped Nanosheets-Assembled Octahedron Zn2SnO4

The current semiconductor sensors cannot detect the ultra-low concentration of triethylamine (TEA). Therefore, this paper uses the catalytic activation effect of precious metal silver and combined with the unique physical and chemical properties of ternary metal oxides to design the Ag-doped Zn <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> SnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> gas sensor to detect the ultra-low concentration of TEA. In this work, spinel-type metal oxides Zn <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> SnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> was prepared by one-step hydrothermal method and its functional modification by means of precious metal doping. The countenance and elemental content of the synthesized products were dissected through diverse means. Combined with the characterization data, it is shown that Zn <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> SnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> samples all present a fixed octahedral shape and the surface is assembled by a large number of nanoplates. The gas sensing test results show that the gas sensor based on 3at% (atom percent) Ag doped Zn <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> SnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> has the best gas sensing performance for TEA. Its response to 100 ppm TEA at 250°C is 273.33. At the same time, the minimum detectable concentration level is 100 ppb. In addition, the material also demonstrates fast response time, good stability and high selectivity. The excellent gas sensing performance is mainly attributed to the synergistic effect of chemical sensitization and electron sensitization of precious metal silver.

Mixed-mode chromatography of mixed functionalized analytes as the homologues of benzalkonium chloride. Application to pharmaceutical formulations

In this work, a retention behavior based on mixed-mode reversed-phase (RP)/hydrophilic interaction liquid chromatography (HILIC) was observed for benzalkonium chloride (BAK) using a core-shell column functionalized with biphenyl groups. Although in the literature, the U-shaped retention was reported for polar compounds in mixed functionalized phases, in the present work, the behavior was dependent upon the chemical structure of the analyte with mixed functionality (ammonium group, a benzyl group and an alkyl chain) and on the high selectivity of the chromatographic column. The bimodal retention was observed for the four BAK homologues using a content of acetonitrile from 65 to 95% in the mobile phase. The data were adjusted to polynomial equations which allow for modeling and predicting the U-shaped retention. The salt concentration (50 and 100 mM), anion (formate and acetate) and cation (ammonium and triethylammonium) of the salt, pH (4 and 5) in the mobile phase were studied in order to understand their influence on the two retention modes. Significant electrostatic interactions were involved in the two retention modes, especially with a content of acetonitrile higher that 90%. Linear relationships between the retention factors of the four homologues were found in a wide range of %acetonitrile when the salt and triethylamine concentration, pH and nature of salt were changed. The differences found on the retention of the homologues, when increasing the alkyl chain length, were more significant in the RP mode due to predominant hydrophobic interactions. A pH decrease and a salt concentration increase caused a retention decrease for both modes. A decrease on of the retention was observed when acetate anion was replaced by formate anion. The different order of the polynomial equations according to the used mobile phase confirmed its relevant role in the interactions with the analytes and stationary phase. A mobile phase was selected (85% acetonitrile, pH 4 and 100 mM ammonium formate) for the BAK determination in cutaneous, otic and ophthalmic formulations with different active pharmaceutical ingredients and excipients. Low sample volume (500 μL) and short analysis time (<5 min) were some of the advantages of the proposed method. In addition, good analytical performance (R2 > 0.999, % RSD <4.5% for intra-day precision and <5.8% for inter-day precision, and recoveries in the 92–105% range) was obtained.

A Chemically Fuelled Molecular Automaton Displaying Programmed Migration of Zn2+ Between Alternative Binding Sites.

A molecular system comprising a cationic zinc complex and an amino acid-derived ambident ligand having phosphate and carboxylate binding sites undergoes a series of rearrangements in which the metal cation migrates autonomously from one site to another. The location of the metal is identified by the circular dichroism spectrum of a ligated bis(2-quinolylmethyl)-(2-pyridylmethyl)amine (BQPA) chromophore, which takes a characteristic shape at each binding site. Migration is fuelled by the decomposition of trichloroacetic acid to CO2 and CHCl3 , which progressively neutralises the acidity of the system as a function of time, revealing in sequence binding sites of increasing basicity. The migration rate responds to control by variation of the temperature, water content and triethylamine concentration, while an excess of fuel controls the duration of an induction period before the migration event.

Mixed potential type sensor based on Gd2Zr2O7 solid electrolyte and BiVO4 sensing electrode for effective detection of triethylamine

Triethylamine (TEA), as a common and widely used industrial raw material, is extremely hazardous to the environment and human health. Therefore, the development of a portable gas-sensing technology for high-efficiency detection of TEA is of great worth for human health and environmental monitoring. In this work, a mixed potential type TEA sensor was initially developed based on pyrochlore Gd2Zr2O7 solid state electrolyte and BiVO4 sensing electrode. The sensor generates high response values of − 62.2 mV and − 134.4 mV to 5 ppm and 100 ppm TEA at 500 °C, respectively. The response value of the sensor displays a logarithmic linear relationship with the concentration of TEA in the range of 1–100 ppm with the sensitivity of − 50.8 mV/decade. Besides, the sensor shows good response and recovery characteristics, and the response and recovery time to 10 ppm TEA is 10 s and 89 s, respectively. Moreover, the sensor possesses good humidity resistance, reproducibility and stability. The sensing behavior of the sensor is explained by the mixed potential sensing mechanism, which is confirmed by the measurement of the polarization curves. This work provides a good supplement for TEA gas sensor, which holds important application value for the sensitive detection of TEA in the environment.

Porous 2D CuO nanosheets for efficient triethylamine detection at low temperature

The freshness of seafood can be judged by detecting the concentration of triethylamine (TEA). In this work, 2D CuO porous nanosheets (CuO PNs) were prepared by a graphene oxide template method and their particle sizes were regulated by changing the calcination temperature. Their structure, morphology and gas sensing performances were investigated by various characterization methods. The response (Rg/Ra) of the gas sensor based on CuO PNs calcined at 700 oC was as high as 440-100 ppm TEA at the operating temperature of 40 °C. The detection limit was as low as 0.25 ppm. In addition, the gas sensor has good selectivity and stability. The excellent TEA sensitivity is mainly resulted from the appropriate particle size and loose porous framework. This work not only paves the way to explore the novel low temperature TEA gas sensors, but also provides deep insight on improving the structure and properties of gas sensitive materials by controlling the calcination temperature.

N-n Heterogeneous MoS2/SnO2 Nanotubes and The Excellent Triethylamine (TEA) Sensing Performances

Considering the different electron structure-related physical properties and their own sensing advantages of MoS2 and SnO2, we report a novel n-n heterogeneous MoS2/SnO2 nanotubes and the excellent triethylamine (TEA) sensing performances. MoS2/SnO2 hollow nanotubes were prepared using electrospinning combined with hydrothermal treatment. The crystal structure, morphology features and microstructure were characterized by XRD, SEM and TEM, etc. Gas sensing investigations show that MoS2/SnO2 sensor exerts preeminent selectivity and high response to TEA at 200 °C. The heterogeneous composite sensor could effectively detect TEA concentration as low as 1 ppm. The response and recovery time to 100 ppm TEA are about 62 s and 153 s, respectively. The sensing mechanism caused by the synergistic effect of n-n type heterojunctions and unique tubular nanostructure are discussed.

Ultrasensitive ppb-level trimethylamine gas sensor based on p–n heterojunction of Co3O4/WO3

Trace poisonous and harmful gases in the air have been harming and affecting people’s health for a long time. At present, effective and accurate detection of ppb-level harmful gas is still a bottleneck to be overcome. Herein, we report a ppb-level triethylamine (TEA) gas sensor based on p–n heterojunction of Co3O4/WO3, which is prepared with ZIF-67 as the precursor and provides Co3O4 deposited tungsten oxide flower-like structure. Due to the introduction of Co3O4 and the 3D flower-like structure of WO3, the Co3O4/WO3-2 gas sensor shows excellent gas sensing performance (1101 for 10 ppm at 240 °C), superb selectivity, good long-term stability and linear response for TEA concentration. Moreover, the experimental results indicate that the Co3O4/WO3-2 gas sensor also possesses a good response to 50 ppb TEA, in fact, the theoretical limit of detection is 0.6 ppb. Co3O4 not only improves the efficiency of electron separation/transport, but also accelerates the oxidation rate of TEA. This method of synthesizing p–n heterojunction with ZIF as the precursor provides a new idea and method for the preparation of low detection limit gas sensors.

Study Of The Stability Of Water-In-Oil Emulsion Intended for the Extraction of Heavy Metals Application: Copper Ions

This work aims to optimize the parameters that affect the stability of a W/O emulsion to exploit it in the extraction of heavy metals contained in the liquid effluents. The study of the emulsion stability shows that; an emulsification time of 10 minutes, a surfactant concentration of Span80 equal to 3% (w/w), an extractant concentration of Triethylamine N(CH2CH3)3 equal to 5% (w/w), an internal phase concentration of phosphoric acid (H3PO4) of 0.75M, a volume ratio of membrane phase to internal phase of 1, a volume ratio of external phase to the emulsion of 20 and a stirring speed of 180 rpm; lead to the formation of a very stable emulsion with a very low rupture rate of around 1.92% after one hour of contact time. The results of extraction of copper ions revealed that under the best operational conditions, the extraction yield was closed to 93.33% for 20% extractant content, a contact time of 12 minutes, and an initial concentration of copper ions of 400 ppm. The application of this new membrane matrix based on phosphoric acid used as inner phase, sorbitan monooleate as a surfactant, and Triethylamine as extractant has been proven effective for extracting copper ions in water.

Enhanced triethylamine-sensing properties of hierarchical molybdenum trioxide nanostructures derived by oxidizing molybdenum disulfide nanosheets

A 3D α-MoO3 nanostructure for high-performance triethylamine (TEA) detection was synthesized via the facial oxidation of MoS2 nanoflowers (NFs) obtained by a hydrothermal process. The influence of the time of hydrothermal process in growing MoS2 on the morphologies of the final MoO3 obtained after calcination was investigated. As-obtained MoO3 and their precursors were systematically characterized by various techniques, such as X-ray diffraction, Raman, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and N2 adsorption–desorption isotherms. Results showed that MoO3 with a hierarchical layered nanostructure was successfully obtained. After hydrothermal treatment of the MoS2 precursor for 20 h, the typical MoO3-based sensor (called M20) exhibited a high response of 2.42 at a very low TEA concentration of only 0.1 ppm at 240 °C. The M20 sensor response to 50 ppm TEA was as high as 125 with a fast response/recovery time of 14/22 s. Moreover, the sensor had a high stability and reproducibility as well as a high selectivity against other interfering VOCs or gases. Due to the tendency of TEA to adsorb to active oxygen sites of MoO3, the enhanced sensing properties of MoO3 can be ascribed to the remarkable hierarchical structure and large surface area. MoO3 obtained after calcination of hydrothermally grown MoS2 is thus a promising sensing material for enhanced TEA gas detection.

Ce0.8Gd0.2O1.95-based mixed potential type triethylamine sensor utilizing La2NiFeO6 sensing electrode

Mixed potential Ce0.8Gd0.2O1.95-based gas sensors utilizing double perovskite type composite oxide La2NiFeO6 – prepared by sol-gel method and sintered at different temperatures – as sensing electrode were fabricated to detect triethylamine (TEA). The influence of the sensing electrode materials with different sintering temperatures on sensing properties of the sensors was mainly studied. Results showed that the sensor utilizing La2NiFeO6 sintered at 1100 °C had the highest response value (−123.2 mV) towards 50 ppm TEA at 490 °C. The greater sensitivity of the sensor was explained by the fact that La2NiFeO6 sintered at 1100 °C had bigger electrochemical active area compared with the other two materials (La2NiFeO6 sintered at 1100 °C/1200 °C), which was confirmed by testing the electric double-layer capacitance (EDLC) of the materials. Besides, the response value of the sensor displayed a linear relationship with the logarithm of TEA concentration, and the slope was −62.2 mV/decade at the range of 0.5–200 ppm TEA. It also displayed good repeatability and selectivity. The fabricated TEA sensor would have good application prospects in the fields spanning from biomedical, chemical detection to seafood safety control.

Triethylamine Sensing with a Mixed Potential Sensor Based on Ce0.8Gd0.2O1.95 Solid Electrolyte and La1-XSrxMnO3 (x = 0.1, 0.2, 0.3) Sensing Electrodes

Introduction The threshold limit of triethylamine concentration is 10 ppm in air by Occupational Safety and Health Administration (OSHA). In addition, it is reported that the concentration of triethylamine at 7 days is less than 4 ppm from rotten crucian (about 200 g) at room temperature, which indicates a great challenge in meeting the requirements of the food freshness test. Recently, gas sensor with low cost and the ability of in-situ measurement has been used to triethylamine detection. The mixed potential sensor based on Ce0.8Gd0.2O1.95 (GDC) has the advantages of high sensing performance, reliable stability and good moisture resistance, which is expected to realize the real-time detection of triethylamine in the atmospheric environment and microenvironment, and to determine the freshness of fish [1, 2]. Method Fabrication and measurement of the gas sensor The sensor was fabricated utilizing Ce0.8Gd0.2O1.95 (GDC) plates (made by Ningbo Sofman Energy Technology Co., Ltd.). A point-shaped and a narrow stripe-shaped Pt electrode were formed on two ends of the GDC plate using a commercial Pt paste (Sino-platinum Metals Co. Ltd.), and sintered at 900°C. The paste which was mixed by a minimum quantity of deionized water and the sensing materials La1-xSrxMnO3 (x = 0.1, 0.2, 0.3). Next, the resultant paste was applied on the point-shade Pt to form stripe-shaped La1-xSrxMnO3 (x = 0.1, 0.2, 0.3) electrode . Afterward, the device was annealed at 800°C to make a good contact between the sensing electrode and electrolyte. A Pt heater and a linear DC Power Supply (Gwinstek GPD-3303S) were used to provide required heat to regulate the operating temperature of the sensor. Results and Conclusions In this paper, CeO2-based mixed potential sensor with La1-xSrxMnO3 (x = 0.1, 0.2, 0.3) and Pt electrodes was developed for the triethylamine detection. It can be seen from Fig. 1(a) that the response value of S2 is the highest, which is -113 mV, so the optimum substitution amount of Sr element in La1-xSrxMnO3 is 20%. Therefore, the sensing performances of the sensor S2, such as the continuous response, sensitivity, selectivity, repeatability and long-term stability were focused in the following content of this study. The dynamic response/recovery transients of the sensor S2 exposed to triethylamine in a concentration gradient 1-200 ppm is shown in Fig. 1(b). It can be seen from the figure that the response value is gradually increasing in the range of 1-100 ppm. When the concentration is higher than 100 ppm, the response value is basically saturated. The response value of sensor S2 to 100 ppm triethylamine is -113 mV, and the sensor S2 is able to detect 1 ppm triethylamine with a response of -8 mV. As shown in Fig.1(c), the typical 90% response time to 100 ppm triethylamine of the sensor S2 is less than 1 s, and the typical 90% recovery time is 9 s. They are quite short time among time cost of the sensors reported. According to the recovery and response curve for sensor S2 to 1-100 ppm triethylamine, the dependence of ΔV on the logarithm of triethylamine concentration for the sensor is shown in Fig. 1(d). A linear relationship between ΔV and the logarithm of concentration towards 1-100 ppm triethylamine at 580°C is shown in the figure, and the sensor S2 displays a sensitivity of -59.2 mV/decade. Next, the cross-sensitivity response of the sensor S2 to 10 ppm various gases (such as ethanol, methanol, methanol, n-butanol and acetone) is shown in Fig. 1(e). It is obvious that the response value of the sensor S2 to triethylamine is much higher than that to other gases, indicating that the sensor S2 has a good selectivity. The continuous response and recovery transient curve of the sensor S2 to 10 ppm triethylamine in five cycles was studied. As shown in Fig. 1(f), the response values remain basically unchanged in the examined five-time cycles, which indicates that sensor S2 displays good repeatability to 10 ppm triethylamine. As shown in Fig. 1(g), the response value of the sensor S2 to 100 ppm triethylamine is basically unchanged under continuous heating to 580°C during 30 days measurement and the sensor S2 exhibited good stability. Taken together, the presented sensor S2 could be considered as a potential sensor for monitoring triethylamine in atmosphere environment and microenvironment, and determining the freshness of fish.

Amino acid derivative reactivity assay-organic solvent reaction system: A novel alternative test for skin sensitization capable of assessing highly hydrophobic substances.

The amino acid derivative reactivity assay (ADRA) is an in chemico alternative to animal testing that focuses on protein binding. The ADRA is a skin sensitization test that solves problems associated with the direct peptide reactivity assay. However, when utilizing the ADRA to evaluate highly hydrophobic substances with octanol/water partition coefficients (logKow) of >6, the test substances may not dissolve in the reaction solution, which can prevent the accurate assessment of skin sensitization. Therefore, we developed the ADRA-organic solvent (ADRA-OS) reaction system, which is a novel skin sensitization test that enables the assessment of highly hydrophobic substances with a logKow of >6. We discovered that the organic solvent ratio, the triethylamine concentration, and the ethylenediaminetetraacetic acid disodium salt dihydrate concentration participate in reactions with the nucleophile N-(2-(1-naphthyl)acetyl)-l-cysteine (NAC) and sensitizers that are used in ADRA and in stabilizing NAC. Thus, we determined the optimal reaction composition of the ADRA-OS according to L9 (33 ) orthogonal array experiments. Using this test, we assessed 14 types of highly hydrophobic substances. When we compared the results with ADRA, we found that ADRA-OS reaction system has high solubility for highly hydrophobic substances and that it has a high predictive capacity (sensitivity: 63%, specificity: 100%, accuracy: 79%). The implication of the results is that the novel ADRA-OS reaction system should provide a useful method for assessing the skin sensitization of highly hydrophobic substances with a logKow of >6.

ВПЛИВ ХІМІЧНИХ ДОМІШОК І МЕХАНО-ХІМІЧНОЇ АКТИВАЦІЇ НА РЕОЛОГІЧНІ ВЛАСТИВОСТІ ВОДОВУГІЛЬНИХ СУСПЕНЗІЙ

It is shown that the use of water-coal fuel mixtures as an energy resource in the production of heat and electric energy can not only significantly expand the resource base of the heat and power industry, but also improve the environmental performance of coal combustion on heat power equipment. One of the main problems of using coalwater fuel is its high viscosity, which complicates the processes of pumping and spraying during combustion. Optimization of the viscosity and other rheological properties of these fuel mixtures is achieved by adding chemical reagents-plasticizers. The experimental studies of the effect on the rheological properties of coal-water fuel mixtures of the use in the process of their production of plasticizers of various origins and modes of mechanochemical activation (grinding of the dispersed phase) have been carried out. For the research, plasticizing reagents were selected, which are used in various technologies for the preparation of water-coal fuel mixtures, and new reagents have been proposed. It was concluded that triethylamine has an advantage in use due to its effectiveness and relatively low cost. In this regard, a study of changes in the rheological properties of coal-water fuel with the addition of this reagent-plasticizer in the range from 0,5 to 3% of the total mass of the fuel mixture was carried out. The graphical dependence of the viscosity of coal-water fuel on the concentration of triethylamine has been obtained. An intensive decrease in fuel viscosity (from 0,95 to 0,8 Pa · s) was revealed in the range of additive concentrations of 0,5-1,0%. The study of the influence of the duration of hydrocavitation mechanochemical activation on the rheological properties of coal-water fuel has been carried out. A graphical dependence of the change in the viscosity of coal-water fuel on the duration of mechanochemical activation, which is characterized by a significant minimum of viscosity at the level of processing duration equal to 60 s, has beenobtained. Keywords: coal-water fuel, mechanochemical activation, plasticizing reagents, dynamic viscosity. Corresponding author V.A. Goman, e-mail: 2409goman@gmail.com