Search Results (25)

Toxic and harmful gases, particularly volatile organic compounds like triethylamine, pose significant risks to human health and the environment. As a result, metal oxide semiconductor (MOS) sensors have been widely utilized in various fields, including medical diagnostics, environmental monitoring, food processing, and chemical production. Extensive research has been conducted worldwide to enhance the gas-sensing performance of MOS materials. However, traditional MOS materials suffer from limitations such as a small specific surface area and a low density of active sites, leading to poor gas sensing properties—characterized by low sensitivity and selectivity, high detection limits and operating temperatures, as well as long response and recovery times. To address these challenges in triethylamine detection, this paper reviews the synthesis of nano-microspheres, porous micro-octahedra, and hollow prism-like nanoflowers via chemical solution methods. The triethylamine sensing performance of MOS materials, such as ZnO and In₂O₃, can be significantly enhanced through nano-morphology control, electronic band engineering, and noble metal loading. Additionally, strategies, including elemental doping, oxygen vacancy modulation, and structural morphology optimization, have been employed to achieve ultra-high sensitivity in triethylamine detection. This review further explores the underlying mechanisms responsible for the improved gas sensitivity. Finally, perspectives on future research directions in triethylamine gas sensing are provided. Full article

Triethylamine is a common volatile organic compound (VOC) that plays an important role in areas such as organic solvents, chemical industries, dyestuffs, and leather treatments. However, exposure to triethylamine atmosphere can pose a serious threat to human health. In this study, gas-sensing semiconductor materials of LaFeO₃ nano materials with different Mo-doping ratios were synthesized by the sol–gel method. The crystal structures, micro morphologies, and surface states of the prepared samples were characterized by XRD, SEM, and XPS, respectively. The gas-sensing tests showed that the Mo doping enhanced the gas-sensing performance of LaFeO₃. Especially, the 4% Mo-doped LaFeO₃ exhibited the highest response towards triethylamine (TEA) gas, a value approximately 11 times greater than that of pure LaFeO₃. Meantime, the 4% Mo-doped LaFeO₃ sensor showed a remarkably robust linear correlation between the response and the concentration (R² = 0.99736). In addition, the selectivity, stability, response/recovery time, and moisture-proof properties were evaluated. Finally, the gas-sensing mechanism is discussed. This study provides an idea for exploring a new type of efficient and low-cost metal-doped LaFeO₃ sensor to monitor the concentration of triethylamine gas for the purpose of safeguarding human health and safety. Full article

High temperature represents a critical constraint in the development of gas sensors. Therefore, investigating gas sensors operating at room temperature holds significant practical importance. In this study, coal-based porous carbon (C-700) and coal-based C/MoO₂ nanohybrid materials were synthesized using a simple one-step vapor deposition and sintering method, and their gas-sensing performance was investigated. The gas-sensing performance for several VOC gases (phenol, ethyl acetate, ethanol, acetone, triethylamine, and toluene) and a 95% RH high-humidity environment were tested. The results indicated that the C/MoO₂-450 sample sintered at 450 °C exhibited excellent specific selectivity towards acetone at room temperature, with a response value of 4153.09% and response/recovery times of 10.8 s and 2.9 s, respectively. Furthermore, the C/MoO₂-450 sample also demonstrated good repeatability and long-term stability. The sensing mechanism of the synthesized materials was also explored. The superior gas-sensing performance can be attributed to the synergistic effect between the porous carbon and MoO₂ nanoparticles. Given the importance of enhancing the high-tech and high-value-added utilization of coal, this study provides a viable approach for utilizing coal-based carbon materials in detecting volatile organic compounds at room temperature. Full article

The objective of the present report was to develop and validate a simple, sensitive, and selective analytical method for the determination of methamphetamine in an odor-adsorbent material (gauze) which was used to improve and standardize the training method used for drug-detection animals. High-performance liquid chromatography (HPLC) was performed using a Spherisorb ODS2 C18 column (200 mm × 4.6 mm, 5 μm), with a mobile phase consisting of a 0.25% methanol/triethylamine aqueous solution (V:V = 20:80), the pH of which was adjusted to 3.1 using glacial acetic acid, at a flow rate of 1.0 mL/min. The column temperature was 25 °C, and the detection of the analytes was performed at a wavelength of 260 nm. Methamphetamine showed good linearity (R² = 0.9999) in the range of 4.2~83.2 mg/mL. The stability of the test material was good over 24 h. The precision of the method was good, with an average spiked recovery of 86.2% and an RSD of 2.9%. The methamphetamine content in the gauze sample was determined to be 7.8 ± 2.2 μg/sample. A high-performance liquid chromatography (HPLC) method was optimized and validated for the determination of methamphetamine in adsorbent materials (gauze). Validation data in terms of specificity, linearity, the limit of detection and the limit of quantification, reproducibility, precision, stability, and recovery indicated that the method is suitable for the routine analysis of methamphetamine in adsorbent materials (gauze) and provided a basis for training drug-detection animals. Full article

A method utilizing high-performance liquid chromatography-fluorescence detection (HPLC–FLD) has been developed and refined for the simultaneous detection of florfenicol (FF) and its metabolite florfenicol amine (FFA) along with three fluoroquinolone (ciprofloxacin (CIP), enrofloxacin (ENR), and sarafloxacin (SAR)) residues in different parts of eggs (whole egg, egg yolk, and egg albumen). The QuEChERS (“Quick, easy, cheap, effective, rugged, and safe”) procedure utilized 0.1 M disodium EDTA solution, water, and acetonitrile as extractants; sodium sulfate, sodium chloride, and trisodium citrate as dehydrating salts; and N-propylethylenediamine and C18 as adsorbents. A dual-channel FLD method was utilized to analyze the target compounds using an XBridge BEH C18 chromatographic column (4.6 mm × 150 mm, 5 μm). The mobile phase was employed isocratically using a solution of 0.01 M sodium dihydrogen phosphate, 0.005 M sodium dodecyl sulfate, and 0.1% triethylamine (pH 4.8) in combination with acetonitrile at a ratio of 65:35 (V/V). The limits of detection (LOD) and quantification (LOQ) of the analytes ranged from 0.03 to 1.5 µg/kg and from 0.1 to 5.0 µg/kg, respectively. The recoveries of the analytes in the blank egg samples ranged from 71.9% to 94.8% when reference standard concentrations of the LOQ, half of the maximum residual limit (MRL), MRL, and twice the MRL were added. The parameters of the presented protocol were validated and subsequently applied to the analysis of real samples, demonstrating the applicability and reliability of the method. Full article

The chromatographic conditions were optimized using headspace gas chromatography, and a simple and rapid method was established for the simultaneous determination of five residual solvents in ursodeoxycholic acid raw materials. The corresponding quality standards were revised. The research results demonstrate that by utilizing a capillary column with a stationary phase consisting of 5% phenyl-95% dimethylpolysiloxane (HP-5, 30 m × 0.32 mm, film thickness 1.0 µm) and a flame ionization detector in conjunction with a headspace injection system and a programmed temperature ramping method, satisfactory analytical results can be achieved. The specific operating conditions are as follows: an initial column temperature of 45 °C, followed by a column temperature increase at a rate of 5 °C per minute up to 60 °C, then a further increase at a rate of 10 °C per minute up to 100 °C, and finally a rapid increase at a rate of 40 °C per minute up to 200 °C, where it is held for 10 min. Nitrogen is employed as the carrier gas at a flow rate of 1 mL/min with a split ratio of 14:1. The headspace vial temperature is maintained at 100 °C, with a sample equilibration time of 45 min. The concentration of methanol ranged from 0.06 mg/mL to 0.3 mg/mL, and the concentrations of acetone, tert-butanol, ethyl acetate, and triethylamine showed a good linear relationship with the peak area within the range of 0.1 mg/mL to 0.5 mg/mL (r = 0.999); The quantitation limits for methanol, acetone, tert-butanol, ethyl acetate, and triethylamine were 4.2, 0.9, 1.5, 1, and 0.1 μg/mL, respectively, with detection limits of 1.2, 0.25, 0.025, 0.3, and 0.025 μg/mL, respectively. The recovery rates of each solvent ranged from 92.9% to 106.0%, with RSD% (n = 9) less than 3.8%; the method exhibited good repeatability, with RSD% (n = 6) less than 2.5%. Furthermore, the robustness is good. The established method is simple, accurate, specific, and highly sensitive, and can be used for the simultaneous and rapid determination of five residual solvents in ursodeoxycholic acid raw materials. Full article

Bioactivity-guided isolation was conducted using centrifugal partition chromatography (CPC) from an extract of Sinomenium acutum rhizome, which has shown promising preventive effects in a dexamethasone-induced C2C12 myotube atrophy model. CPC was operated with a solvent system of n-butanol–acetonitrile–water (10:2:8, v/v/v, containing 0.5% triethylamine) in dual mode (ascending to descending), which provided a high recovery rate (>99%) with a high resolution. Then, the preventive effects of the obtained CPC fractions were examined against dexamethasone-induced atrophy in C2C12 myotubes according to the weight ratios of the obtained fractions. The active fractions were further purified by semi-preparative HPLC that led to obtaining five alkaloids, one lignan glycoside, and one phenylpropanoid glycoside. Among these, at a concentration of 1 nM, sinomenine, magnoflorine, and acutumine could ameliorate dexamethasone-induced myotube atrophy in C2C12 myotubes by 9.3%, 13.8%, and 11.3%, respectively. Full article

Rapid detection of harmful estrogens in cosmetics is essential in protecting public health. To reduce time-consuming pretreatment and analytical procedures, a novel reactive paper spray ionization mass spectrometry (RPSI-MS) methodology was developed. RPSI-MS is suitable for quantitatively analyzing estrogens in cosmetics by utilizing an online derivatization reaction between estrogens and 2-fluoro-1-methyl-pyridinium-p-toluene-sulfonate (FluMP). Using estradiol valerate as the internal standard (I.S.), three estrogens, estradiol, estriol, and ethinyloestradiol, in cosmetics were quantitatively characterized within minutes. Multiple parameters were optimized including FluMP concentration and volume, triethylamine amount as well as the drying time. The three estrogens displayed good linearity ranging from 0.002 to 1 μg/mL, with R² above 0.99. The recovery results of all the estrogens were within 80~111%. The limit of detection (LOD) was 0.001 μg/mL for the three estrogens. Compared to conventional paper spray ionization mass spectrometry (PSI-MS), extraction is not required and the detection sensitivity of RPSI-MS was improved by 34,000, 80,000, and 1400 times for estradiol, estriol, and ethinyloestradiol, respectively. The protocol established in this paper is sensitive, eco-friendly, and suitable for rapid testing of estrogens in cosmetics. Full article

Noble Metal nanoclusters (NCs) are promising electrochemiluminescence (ECL) emitters due to their amazing optical properties and excellent biocompatibility. They have been widely used in the detection of ions, pollutant molecules, biomolecules, etc. Herein, we found that glutathione-capped AuPt bimetallic NCs (GSH-AuPt NCs) emitted strong anodic ECL signals with triethylamine as co-reactants which had no fluorescence (FL) response. Due to the synergistic effect of bimetallic structures, the ECL signals of AuPt NCs were 6.8 and 94 times higher than those of monometallic Au and Pt NCs, respectively. The electric and optical properties of GSH-AuPt NCs differed from those of Au and Pt NCs completely. An electron-transfer mediated ECL mechanism was proposed. The excited electrons may be neutralized by Pt(II) in GSH-Pt and GSH-AuPt NCs, resulting in the vanished FL. Furthermore, abundant TEA radicals formed on the anode contributed electrons to the highest unoccupied molecular orbital of GSH-Au_2.5Pt NCs and Pt(II), booming intense ECL signals. Because of the ligand effect and ensemble effect, bimetallic AuPt NCs exhibited much stronger ECL than GSH-Au NCs. A sandwich-type immunoassay for alpha fetoprotein (AFP) cancer biomarkers was fabricated with GSH-AuPt NCs as signal tags, which displayed a wide linear range from 0.01 to 1000 ng·mL⁻¹ and a limit of detection (LOD) down to 1.0 pg·mL⁻¹ at 3S/N. Compared to previous ECL AFP immunoassays, this method not only had a wider linear range but also a lower LOD. The recoveries of AFP in human serum were around 108%, providing a wonderful strategy for fast, sensitive, and accurate cancer diagnosis. Full article

Biopolymers obtained from natural macromolecules are noteworthy among materials presenting high biocompatibility and adequate biodegradability, as is the case of chitosan (CS), making this biopolymeric compound a suitable drug delivery system. Herein, chemically-modified CS were synthetized using 2,3-dichloro-1,4-naphthoquinone (1,4-NQ) and the sodium salt of 1,2-naphthoquinone-4-sulfonic acid (1,2-NQ), producing 1,4-NQ-CS and 1,2-NQ-CS by three different methods, employing an ethanol and water mixture (EtOH:H₂O), EtOH:H₂O plus triethylamine and dimethylformamide. The highest substitution degree (SD) of 0.12 was achieved using water/ethanol and triethylamine as the base for 1,4-NQ-CS and 0.54 for 1,2-NQ-CS. All synthesized products were characterized by FTIR, elemental analysis, SEM, TGA, DSC, Raman, and solid-state NMR, confirming the CS modification with 1,4-NQ and 1,2-NQ. Chitosan grafting to 1,4-NQ displayed superior antimicrobial activities against Staphylococcus aureus and Staphylococcus epidermidis associated with improved cytotoxicity and efficacy, indicated by high therapeutic indices, ensuring safe application to human tissue. Although 1,4-NQ-CS inhibited the growth of human mammary adenocarcinoma cells (MDA-MB-231), it is accompanied by cytotoxicity and should be considered with caution. The findings reported herein emphasize that 1,4-NQ-grafted CS may be useful in protecting injured tissue against bacteria, commonly found in skin infections, until complete tissue recovery. Full article

In this work, a sorbent was prepared from wastepaper samples enriched with iron oxide particles and graphene oxide and used in the solid phase extraction of antibiotics. The precursor underwent a carbothermal reduction to promote the formation of paramagnetic phases useful for the recovery of the sorbent during the analysis, and to disperse and fix graphene and the iron oxide in a durable way throughout the cellulose structure. Characterizations were carried out to evaluate the composition (Raman, XRD and EDX) and the morphological structure (SEM) of the material. A UHPLC-PDA method was developed for the simultaneous determination of antibiotics from different drug families (carbapenems, fluoroquinolones, β-lactams) using a 120 SB-C 18 poroshell column (50 × 2.1 mm I.D., 2.7 um particle size) and a mobile phase consisting of 10 mM acetate buffer at pH 5 (Line A) and acetonitrile (Line B) both containing 0.1% of triethylamine. A gradient elution was used for the separation of the analytes, while for the quantitative analysis each analyte was determined at its maximum wavelength. Several experiments were carried out to evaluate the influence of different parameters involving the dispersive magnetic solid phase extraction of these analytes. Samples were extracted using 25 mg of sorbent at pH 5 and desorbed in 5 min using methanol. We report herein on some of the outstanding advantages of using carbon-based sorbent, such as lower toxicity, scalability, improved absorption capacity, target selectivity and stability in acidic medium. Moreover, from the results obtained it is evident that, despite the use of some recycled materials, the performances obtained were comparable or even superior to the methods reported in the literature. Full article

The success of adeno-associated virus (AAV)-based therapeutics in gene therapy poses the need for rapid and efficient processes that can support the growing clinical demand. Nonwoven membranes represent an ideal tool for the future of virus purification: owing to their small fiber diameters and high porosity, they can operate at high flowrates while allowing full access to target viral particles without diffusional limitations. This study describes the development of nonwoven ion-exchange membrane adsorbents for the purification of AAV2 from an Sf9 cell lysate. A strong anion-exchange (AEX) membrane was developed by UV grafting glycidyl methacrylate on a polybutylene terephthalate nonwoven followed by functionalization with triethylamine (TEA), resulting in a quaternary amine ligand (AEX-TEA membrane). When operated in bind-and-elute mode at a pH higher than the pI of the capsids, this membrane exhibited a high AAV2 binding capacity (9.6 × 10¹³ vp·mL⁻¹) at the residence time of 1 min, and outperformed commercial cast membranes by isolating AAV2 from an Sf9 lysate with high productivity (2.4 × 10¹³ capsids·mL⁻¹·min⁻¹) and logarithmic reduction value of host cell proteins (HCP LRV ~ 1.8). An iminodiacetic acid cation-exchange nonwoven (CEX-IDA membrane) was also prepared and utilized at a pH lower than the pI of capsids to purify AAV2 in a bind-and-elute mode, affording high capsid recovery and impurity removal by eluting with a salt gradient. To further increase purity, the CEX-IDA and AEX-TEA membranes were utilized in series to purify the AAV2 from the Sf9 cell lysate. This membrane-based chromatography process also achieved excellent DNA clearance and a recovery of infectivity higher that that reported using ion-exchange resin chromatography. Full article

A simple, precise, and cost-effective reverse phase ion pair chromatographic (RP-IP-HPLC) method was developed and validated for the determination of Ephedrine Hydrochloride in a nasal ointment. A simple and fast extraction protocol was developed for the effective recovery of the analyte, and for this purpose, Bromhexine Hydrochloride was used as the internal standard. The mobile phase consisted of MeOH, Sodium Lauryl Sulfate (SLS) 49.8 mM, triethylamine (ET₃N) in the ratio of 65:34.6:0.4%, respectively, with pH = 2.20. The detection of the compounds was carried out at 206 nm, and we used a PDA detector. A short run time was achieved with retention times of 6.3 min and 9.8 min for ephedrine hydrochloride and the internal standard, respectively. The proposed method was validated according to ICH guidelines. Linearity was confirmed in the range of 50–150 μg/mL. Recoveries results were within the range of 98–102% and precision < 2% for the analyte in spiked blank matrix. Robustness testing was conducted via a fractional factorial experimental design. The method was found to fulfill the required specifications for specificity and stability for both standard solutions and samples, as well and applied to the determination of ephedrine hydrochloride in nasal ointments produced by the Greek Military Pharmaceutical Laboratories. Full article

The method of using high-performance liquid chromatography with a charged aerosol detector method (HPLC-CAD) was developed for the separation and determination of phospholipids isolated from cell membranes. The established cell lines—normal and neoplastic prostate cells and normal skin fibroblasts and melanoma cells—were selected for the study. Chromatographic separation was performed in the diol stationary phase using a gradient elution based on a mixture of n-hexane, isopropanol and water with the addition of triethylamine and acetic acid as buffer additives. Taking the elements of the Folch and Bligh–Dyer methods, an improved procedure for lipid isolation from biological material was devised. Ultrasound-assisted extraction included three extraction steps and changed the composition of the extraction solvent, which led to higher recovery of the tested phospholipids. This method was validated by assessing the analytical range, precision, intermediate precision and accuracy. The analytical range was adjusted to the expected concentrations in cell extracts of various origins (from 40 µg/mL for PS up to 10 mg/mL for PC). Both precision and intermediate precision were at a similar level and ranged from 3.5% to 9.0%. The recovery for all determined phospholipids was found to be between 95% and 110%. The robustness of the method in terms of the use of equivalent columns was also confirmed. Due to the curvilinear response of CAD, the quantification was based on an internal standard method combined with a power function transformation of the normalized peak areas, allowing the linearization of the signal with an R² greater than 0.996. The developed method was applied for the isolation and determination of glycerophospholipids from cell membranes, showing that the profile of the tested substances was characteristic of various types of cells. This method can be used to assess changes in metabolism between normal cells and neoplastic cells or cells with certain pathologies or genetic changes. Full article

Shale inhibitor is an additive for drilling fluids that can be used to inhibit shale hydration expansion and dispersion, and prevent wellbore collapse. Small molecular quaternary ammonium salt can enter the interlayer of clay crystal, and enables an excellent shale inhibition performance. In this paper, a novel ionic shale inhibitor, triethylammonium acetate (TEYA), was obtained by solvent-free synthesis by using acetic acid and triethylamine as raw materials. The final product was identified as the target product by Fourier transform infrared spectroscopy (FT-IR). The inhibition performance of TEYA was studied by the mud ball immersion test, linear expansion test, rolling recovery test and particle size distribution test. The results demonstrated that the shale inhibitor shows a good shale hydration inhibition performance. The inhibition mechanism was studied by FT-IR and X-ray diffraction (XRD), respectively; the results showed that triethylammonium acetate TEYA could enter the crystal layer of clay and inhibit it through physical adsorption. Full article