Amine Vapors Research Articles

Rapid response to amine vapor based on fluorescent light-up sensor for real-time and visual detection of crawfish and fish freshness

Biogenic amines are generally produced from the degradation of amino acids in biometabolism, which can be used as an important biomarker for food spoilage. Rapid, simple and accurate detection of biogenic amines is an important task for the food safety. Here we synthesize a series of coumarin hydrozone derivatives with high solid-state emission. BDCH2 exhibits a fluorescent switch between the yellow emission (λem,max = 555 nm) and the NIR region (λem,max = 720 nm) upon HCl/NH3 vapor stimuli. The response time for NH3 vapor is only 2 s. Utilizing this property, BDCH2 as a biogenic amine vapors sensor can be readily applied in the detection of food spoilage for real-time and visual monitoring the freshness of crawfish and fish with quick response, easy visualization and simple operation.

Luminescent monomeric and dimeric Ru(ii) acyclic carbene complexes as selective sensors for NH3/amine vapor and humidity.

A new class of luminescent bis(bipyridyl) Ru(ii) pyridyl acyclic carbene complexes with environmentally-sensitive dimerization equilibrium have been developed. Owing to the involvement of the orbitals of the diaminocarbene ligand in the emissive excited state, the phosphorescence properties of these complexes are strongly affected by H-bonding interactions with various H-bonding donor/acceptor molecules. With the remarkable differences in the emission properties of the monomer, dimer, and H-bonded amine adducts together with the change of the dimerization equilibrium, these complexes can be used as luminescent gas sensors for humidity, ammonia, and amine vapors. With the responses to amines and humidity and the corresponding change in the luminescence properties, a proof-of-principle for binary optical data storage with a reversible concealment process has been described.

A new ESIPT-based fluorescent probe for the highly sensitive detection of amine vapors

A new ESIPT-based fluorescent probe has been developed as a rapid, highly sensitive, and selective sensor for amine vapors.

Aerosol Emissions from Water-lean Solvents for Post-combustion CO2 Capture

Advanced water-lean solvents (WLS) for post-combustion CO2 capture have been gaining interest due to their ability to reduce the parasitic penalty from energy needed for solvent regeneration. Commercial implementation of these novel CO2 capture technologies hinges on successful control of amine emissions. RTI conducted a parametric study of fundamental and operational variables influence on overall amine aerosol and vapor emissions from our water-lean solvent eCO2Sol™ using our 6-kW equivalent bench-scale gas absorption system. The parametric testing used a simulated flue gas with 15 % CO2, 2.3–4.2 % H2O, and 0–6 ppm sulfite (SO3) to examine the impact of the presence of aerosols to the capture performance and amine emissions from the system. The SO3 reacts with water in the flue gas to create H2SO4, which forms liquid aerosol droplets and provide nucleation sites for growth of aerosols. Scanning Mobility Particle Sizer and Aerodynamic Particle Sizer instruments monitored the aerosol particle size distribution. Parametric testing results suggested that the presence of the aerosols in the flue gas could increase the overall amine emissions by 10X compared to the baseline emissions from WLS’s vapor pressure. Principal component analysis (PCA) and projection to latent squares (PLS) developed models to predict the aerosol-based amine emissions from process data. The predictive PLS model had a correlation coefficient (Q2) of 0.92 and could predict the aerosol-based emissions from the NAS process with ±15 % accuracy (average absolute deviation, AAD). The PLS regression model also identified key variables affecting aerosol-based emissions from WLS.

Mechanism for Rapid Conversion of Amines to Ammonium Salts at the Air-Particle Interface.

The effect of sulfuric acid (SA) concentrations on heterogeneous reactions of amines such as methylamine (MA), dimethylamine (DMA), and trimethylamine (TMA) at the air-particle interface is investigated using combined classical molecular dynamics, Born-Oppenheimer molecular dynamics, and quantum chemical calculations. The results show that the mixtures of these amine vapors can accumulate at the air-particle interface and then participate in two types of heterogeneous reactions depending on the SA concentrations in the aqueous particles. At high SA concentrations, amines are neutralized by H3O+ and form ammonium salts within only a few picoseconds. At low SA concentrations, amines mainly proceed by hydrolysis reactions and produce ionic pairs of ammonium and OH-. However, the formed ionic pair is extremely unstable, and the reverse reaction takes place. Considering that the salt conversion time scales of amines at high SA concentrations are 2.5-15 times faster than those at low SA concentration, amine accumulation at high acidity particles is more favored.

A “Turn-on” fluorescence perovskite sensor based on MAPbBr3/mesoporous TiO2 for NH3 and amine vapor detections

Recently, lead halide perovskites have attracted great interest in toxic gas detection, but as gas sensor, it is still a challenge to achieve their high-performance. Here, we propose a novel “turn-on” fluorescence NH3/amine vapor sensor by depositing the CH3NH3PbBr3 (MAPbBr3) on the mesoporous TiO2 (mp-TiO2) layer. The fluorescence intensity of the sensor increases rapidly within seconds upon exposure to NH3 gas (72 % at 5 ppm and 988 % at 100 ppm, respectively) with excellent reversibility, high gas selectivity, humidity insensitivity, and regeneration. Moreover, the sensor can be further used for detecting various amine vapors, including methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, and decylamine. We presumed the “turn-on” fluorescence sensing mechanism is that the trace NH3 or amine molecules could decrease the surface trap defects and facilitate the formation of passivation layer. It will impede the electron-injection into mp-TiO2, which induces the radiative electron-hole recombination and fluorescence enhancement. This research demonstrates that it is feasible to design a “turn-on” fluorescence gas sensor based on the mp-TiO2-based perovskite.

An edible genipin‐based sensor for biogenic amine detection

AbstractBACKGROUNDFood is often wasted due to real or perceived concerns about preservation and shelf life. Thus, precise, accurate, and consumer‐friendly methods of indicating whether food is safe for consumers are drawing great interest. The colorimetric sensing of biogenic amines released as food degrades is a potential way of determining the quality of the food. Herein, we report the use of the fruit extract genipin, a naturally occurring iridoid that reacts selectively with primary amines, as a colorimetric sensor for biogenic amines under conditions that mimic food degradation.RESULTSGenipin was shown to react with four biogenic amines: putrescine, cadaverine, tyramine, and histamine, resulting in a dark blue dye under atmospheric conditions (λmax ~ 600 nm). In the absence of oxygen gas, this reaction provided a different response, instead yielding a red dye. Genipin was immobilized in edible calcium alginate beads and the gel beads were exposed to putrescine vapors and chicken samples. In both cases, the formation of blue dye demonstrated proof‐of‐concept that immobilized genipin can sense gaseous biogenic amines in timeframes and conditions relevant to food spoilage.CONCLUSIONGenipin can act as a highly selective, qualitative sensor for both biogenic amines and oxygen gas. Since food spoilage is triggered by O2, the dual colorimetric response that genipin has uniquely positions it as a promising sensor for food spoilage. By immobilizing the sensor in an edible calcium alginate matrix, biogenic amine vapors were detected at low concentrations. © 2020 Society of Chemical Industry (SCI)

Selection of crosslinkers and control of microstructure of vapor-phase crosslinked composite membranes for organic solvent nanofiltration

A fast and green chemical modification method has been developed by using amine vapor to fabricate hybrid composite membranes consisting of crosslinked polyimides and nano-size UiO-66-NH2 metal-organic frameworks (MOFs) with higher selectivity for organic solvent nanofiltration (OSN). Three amine vapor-phase crosslinking (VPC) reagents; namely, N,N′-Bis(3-aminopropyl)-1,3-propanediamine (APPD), 1,4-Bis(3-aminopropyl) piperazine (BAPP) and polyethylenimine (PEI) were employed. It was found that APPD and PEI vapor are more effective to generate smaller pores in the dense-selective layer than the BAPP vapor. In addition, the PEI modified membranes are more suitable for polar and aprotic solvents nanofiltration applications, while the APPD and BAPP modified membranes are for applications involving wider solvents. The selected hybrid membranes cast on polyester (PET) non-woven fabrics have rejections of tetracycline (MW = 444 gmol-1) more than 90% in four organic solvents under continuous cross-flow filtration tests for over 120 h. All fluxes and selectivities remain stable without showing significant fluctuations, evidencing great potentials of designed membranes for industrial applications. Besides, the VPC modification process is environmental-friendly because it uses a tiny amount of amine vapors without extra chemical waste production. Therefore, this study offers a promising sustainable, greener and scalable strategy to produce high performance OSN membranes.

Tri(pyridinyl)pyridine Viologen-Based Kagome Dual Coordination Polymer with Selective Chromic Response to Soft X-ray and Volatile Organic Amines.

The development of new responsive smart materials has been highly desirable in the recent decade due to growing demand in our daily life, and extended viologen-based coordination polymers are regarded as proper and promising candidates for stimuli-responsive study. A tri(pyridinyl)pyridine viologen-based Kagome dual (kgd) topological coordination polymer, [Mn3Cl4(tpptb)2]·Cl2·(H2O)2, (tpptb = N,N',N″-tri(3-carboxybenzyl)-2,4,6-tri(pyridinium-4-yl)pyridine; 1) has been solvothermally synthesized, which can selectively respond to soft X-ray Al-Kα (λ = 8.357 Å) irradiation but not to UV light and hard X-rays of λ < 1.5418 Å at room temperature. Appealingly, 1 is very sensitive and convenient for the visual detection of various volatile amine vapors, especially ethylamine vapors at a low concentration of 100 ppm, and the vapochromic sample can be recovered after exposure in the air at room temperature. The sequence of amines in vapochromism could be rationalized by combined consideration of vapor pressure, the molecular size, and electron-donor ability of various amine molecules as well as the void spaces of 1. In addition, 1 exhibits an obvious hydrochromic transformation upon heating in the air and an anhydrous atmosphere. Combined XPS and EPR confirmed that these physical and chemical stimuli can cause electron transfer from electron-rich groups to quaternary nitrogen atoms of the ligand to generate charge-separated radicals, leading to soft X-ray-induced photochromic and selective vapochromic behavior of 1. Such behavior indicates that it will become a convenient, recyclable, and practical multifunctional material for chemical and environmental sensing. These results provide an effective avenue for the rational design and synthesis of multifunctional chromic materials for potential use in sensing devices.

A reversible vapor-responsive fluorochromic molecular platform based on coupled AIE–ESIPT mechanisms and its applications in anti-counterfeiting measures

In this work, a series of 2-(2-hydroxyphenyl)benzothiazole (HBT) derivatives with an aggregation-induced emission–excited state intramolecular proton transfer (AIE-ESIPT) dual mechanism was synthesized. We systematically investigated their optical properties in solution, aqueous suspension, and the solid state. The fluorescence properties of these five compounds were highly dependent on the solvent environment. Particularly, DMSO and DMF were found to significantly promote deprotonation of the phenolic hydroxyl and favor fluorescence emission from the phenolic anion. The Keto or Enol forms generally could be transformed to phenolic anions with the aid of base in solution. The results from aggregation-induced emission enhancement (AIEE) and red-shifted AIE clearly illustrated the evolution process of the fluorescence spectra, indicating that the three luminescent species in the solution were transformable. The systematic investigation demonstrated that the desired fluorescence could be generated for HBT derivatives by varying the solvents or adding additives, such as base or water, to the solution. Because of the synergistic effect of AIE and ESIPT, these fluorophores exhibited high solid-state quantum yields and large Stokes shifts. These dyes also featured high photostability and tunable emission spectra covering most of the visible light region. Single crystal studies and theoretical calculations elucidated the luminescent properties. When loaded on filter paper, the HBT-based dyes exhibited high-efficiency fluorescence visualization and reversible solid-state luminescence switching under alternating amine and acid vapor treatments. These dyes were used on banknotes for anti-counterfeiting measures, demonstrating the practical applications of these molecules as security inks.

Semi-quantitative evaluation of seafood spoilage using filter-paper strips loaded with an aggregation-induced emission luminogen

The method for seafood spoilage detection is far from satisfactory for ensuring food safety and security. Here, we develop a simple and cost-effective method using the filter papers loaded with a dihydroquinoxaline derivative (H + DQ2) to monitor salmon spoilage. The correlation between the content of solid biogenic amines and the photoluminescence intensity (PL) of H + DQ2 induced by amine vapours showed that the PL intensities of H + DQ2 increased with the increase of spoilage, which indicates that it is feasible to evaluate the spoilage degree of salmon based on the PL intensity of H + DQ2-loaded filter papers by semi-quantitation. The optimum detection condition is 75, 50 and 50 g of salmon, 75, 25 and 10 µM H + DQ2 at 0, 4 and 25 °C, respectively. This study provides a quick and simple way for testing amine vapour from fish and provides baseline information for developing an easy-to-use on-site method to evaluate seafood quality for customers.

A Solid-State Luminescent Cd(II) Supramolecular Coordination Framework Based on Mixed Luminophores as a Sensor for Discriminatively Selective Detection of Amine Vapors.

A novel Cd(II) supramolecular coordination framework containing mixed functionalized luminophore ligands, namely, [Cd(AS)2(phen)2]EtOH or 1 (where AS = 4-aminosalicylate, phen = 1,10-phenanthroline, EtOH = ethanol), was successfully synthesized as a solid-state luminescent sensor for the detection of amine vapors. The single-crystal X-ray diffraction analysis revealed that 1 possesses a three-dimensional (3D) supramolecular framework enclosing ethanol molecule in the lattice. The supramolecular structure is well-stabilized by various noncovalent intermolecular interactions through functional groups of ligands. Compound 1 shows an intense yellow solid-state emission and displays a reversibly discriminative luminescent response to NH3 and ethylenediamine (EDA) vapors through very large blue-shifted luminescent spectra with distinguishable emission colors under UV light. This work reports the first time for selective luminescent sensing of NH3 and EDA vapors with considerably different emission color change. A sensing mechanism has been confirmed by density functional theory and time-dependent density functional theory calculations that agrees well with the experimental results. Also, 1 exhibits a good recyclability over five cycles for sensing of NH3 and EDA vapors.

Dithienylethene-bridged difluoroboron β-diketonate dyes: Optical switching behaviors and triple sensing for volatile amine vapors

Developing new visible light-triggered NIR photochromic sensors for the accurate detection of volatile amine vapors in the solid state is highly desirable. Herein, three novel dithienylethene-bridged difluoroboron β-diketonate dyes Di-BF2bdk-DTE1-Di-BF2bdk-DTE3, in which BF2bdk group not only functions as electron acceptor but also responds to amine vapors, have been developed. Upon alternating irradiation with blue light (460–470 nm) and near-infrared light (760–770 nm), they displayed excellent NIR photochromism and fluorescent switching behaviors in toluene and in the PMMA film. Moreover, they showed an unprecedented triple sensing performance for volatile n-propylamine vapor in the PMMA film state (fluorescent-colorimetric-colorimetric). Therefore, they would be utilized as triple sensing membranes for selective detection towards volatile primary or secondary amine vapors in environmental and biological systems.

Novel difluoroboron complexes of curcumin analogues as “dual-dual” sensing materials for volatile acid and amine vapors

The development of near-infrared difluoroboron complexes of curcumin analogues to specifically detect one or both analytes in the solid state is highly desirable. Herein, three novel BF2-curcumin analogues with an extended π-conjugation (TBN, TBT and NBN) have been rationally designed and developed, in which the dimethylamino group acted as electron donator (D) and the proton-binding site, and the BF2bdk moiety not only functioned as electron acceptor (A) but also responded to amine vapors. And they exhibited excellent solvent-dependent photophysical properties in solutions and PMMA film state. Moreover, BF2-curcumin analogues TBN and NBN showed an unprecedented “dual-dual” sensing performance (the first dual: simultaneous response to both acid and amine vapors; the second dual: fluorescent turn-on sensing and colorimetric sensing) in solutions and PMMA film state. Therefore, they would be utilized as multifunctional sensing materials for specific detection towards volatile acid and amine vapors in environmental and biological systems.

A Calixarene Promotes Disaggregation and Sensing Performance of Carboxyphenyl Porphyrin Films.

The aggregation of a free base porphyrin, meso-tetrakis(4-carboxyphenyl)porphyrin and its Zn(II) derivative have been studied at the air/water interface in the presence of a p-tert-butylcalyx[8]arene matrix. The mixed Langmuir films were obtained either by premixing the compounds (cospreading) or by sequential addition. The negative deviation from the additivity rule of the cospread films is indicative of a comparatively good miscibility that was further confirmed by Brewster angle microscopy. The images of the cospread mixed films showed a more homogeneous morphology in comparison with those of pure porphyrin that is attributed to a deeper and earlier self-aggregation state at the interface of the latter. These results were similar for both porphyrins and revealed the disaggregating effect of the calixarene matrix. The orientation and association of the porphyrins were studied by UV–visible reflection spectroscopy at the interface. A different aggregation behavior can be inferred from the resulting spectra, and a higher orientational freedom was observed when the molecules were less aggregated in mixed cospreaded films. The disaggregating effect was retained when the films were transferred to solid supports as demonstrated by UV–visible spectroscopy. Finally, the potential use of these Langmuir–Blodgett films as optical gas sensors was tested against ammonia and amine vapors. The changes in the spectrum in the presence of the volatile compounds are higher for the Zn-porphyrin. The presence of calixarene enhances the sensor response due to the higher accessibility of volatiles to disaggregated porphyrins in the mixed films. The resulting changes were mapped into a numerical matrix that can be transformed into a color pattern to easily discriminate among these gases.

Discrimination of Various Amine Vapors by a Triemissive Metal-Organic Framework Composite via the Combination of a Three-Dimensional Ratiometric Approach and a Confinement-Induced Enhancement Effect.

Multiemissive sensors are being actively pursued, because of their ratiometric luminescent detection capabilities, which demonstrates better sensitivity and selectivity than conventional single-emission sensors. Herein, we present a trichromatic white-light-emitting metal-organic framework (MOF) composite (Z3) by simultaneously incorporating red/green-emitting Pt/Ru complex cations into porous blue-emitting bio-MOF-1 through post-synthetic modification. With the help of a three-dimensional (3-D) dual-ratiometric luminescence recognition method, and unique turn-on responses of the red emission toward amine compounds (ACs), including NH3 and aliphatic amines, via confinement-induced luminescence enhancement effect, Z3 can work as a dual-ratiometric luminescent sensor for discrimination of 7 out of 11 AC vapors. This work not only provides a new AC sensing mechanism (confinement effect) that can induce a "turn-on" response but also proves that the accuracy and selectivity of composite sensor can be greatly improved through the combination of 3-D recognition method and the confinement effect. Thus, it open up fresh opportunities to develop composite sensors with excellent sensing and differentiating ability.

Rapid Visual Detection of Amines by Pyrylium Salts for Food Spoilage Taggant.

Amines are ubiquitous in biological world, but are toxic and harmful in nature. Detection of biogenic amines that are released from spoiled seafood, meat, or dairy products is an important task to maintain the quality and safety of these packaged foods. To this endeavor, herein we report pyrylium salts that are capable of sensing various amines by rapid change of fluorescence color or intensity. In molecular level, this change of fluorescence is rooted to the formation of pyridine or analogous product that have distinct optical property. The pyrylium salts are capable of efficiently sensing amine vapors or amine solutions both in solid state and in solution state and thus demonstrating a multiphase sensing platform. Utilizing the excellent sensing property, we have employed our pyrylium compounds as spoilage indicator for food products such as fish, meat or cheese which relies on sensing biogenic amines released from these spoiled foods and provide optical response. Prominent change in visible and luminescence color was observed within 4-18 h of packaging at room temperature (∼33 °C). Considering the rapid response for biogenic amines, these molecular sensors have great potential to be utilized for food packaging industry, medical diagnostics, or other sensory devices.

Luminescent complexes of iridium(iii) with aliphatic amines and detection of biogenic amines

The straightforward reaction of [Ir2(ppy)4(µ-Cl)2] with an excess of aliphatic amines yields luminescent iridium complexes of general formula [IrCl(ppy)2(amine)] [amine = n-octylamine (1), t-butylamine (2), piperidine (3)]. The higher sterical hindrance of the amine in complex 2 was the responsible of its equilibrium with the starting materials. The luminescence of 1 and 3 has been studied showing emission at 508 and 509 nm respectively. As the aliphatic amines can be considered models of biogenic amines, this luminescence has been used to explore the viability of this reaction in the detection of biogenic amines. The exposition to vapors of biogenic amines of a solution of [Ir2(ppy)4(µ-Cl)2] in CH2Cl2 or in different solid supports, showed that it was possible to detect the amines in a quick and easy way, with limits of detection value (in solution of methylene chloride) of 4.8 µM for cadaverine.

Multi-stimuli responsive cyanostilbene derivatives: pH, amine vapor sensing and mechanoluminescence

Two carboxyl substituted cyanostilbene derivatives can serve as novel mechanoluminescence materials and fluorescent sensors towards pH change and also amine vapors.

A multifunctional photochromic metal–organic framework with Lewis acid sites for selective amine and anion sensing

A bipyridinium-based MOF was prepared, which exhibits reversible photochromic properties, good luminescence sensing ability for Cr2O72−, and can be considered an excellent colorimetric sensor for the selective detection of amine vapors.