Aldehyde Vapors Research Articles

A UOF based on a cyclotriphosphazene skeleton: fluorescence sensing of different substituted aldehydes and NACs.

A novel uranyl organic framework (U-hdpcp) based on flexible cyclic triphosphazene polycarboxylate ligands was prepared, which possesses the ability to sense aromatic aldehyde solutions (benzaldehyde, salicylaldehyde and 2-bromobenzaldehyde) and nitro compounds (2,4,6-trinitrophenol, 2,4-dinitrophenol and o-nitrophenol). A fluorescent thin film based on U-hdpcp@PVA with the ability to sense aldehyde vapors was prepared via a spin coating method. The work expands the library of UOF materials based on large-sized carboxylic acid ligands and demonstrates promising applications in the field of fluorescent sensors.

Achieving Multifunctional Detection of Th4+ and UO22+ in the Post‐Synthetically Modified Metal–Organic Framework and Application of Functional MOF Membrane

AbstractThe field of post‐synthesis modification has aroused widespread concern from diverse perspectives, including chemistry, biology, and material science. Post‐synthesis modification can introduce rich functionality into metal–organic frameworks (MOFs) without destroying the main structure of MOFs. Based on this research status, a series of lanthanide metal–organic frameworks ([Ln2(NH2‐BDC)2.5(CH3COO)(DMA)(H2O)]•DMA, Ln = Pr, Nd, Sm, Eu, Gd and Tb, NH2‐BDC = 2‐aminoterephthalic acid, DMA = N,N‐Dimethylacetamide) with 3D network structures, are synthesized by hydrothermal synthesis. Due to the presence of uncoordinated amino groups in the ligands, a series of post‐synthesis modified compounds are successfully synthesized through aldimine condensation reaction. Based on the good fluorescence properties and stable structure of coordination polymers and post‐synthesis modified compounds in water or organic solvents, they are able to be used as potential fluorescence sensor for the detection of Th4+, UO22+, and Cr2O72−, and the calculation result shows that the post‐synthesis modified compounds are more sensitive to the detection of analytes (Th4+, UO22+ and Cr2O72−) than coordination polymers. In addition, the MOF membrane prepared by self‐assembly of [Eu2(NH2‐BDC)2.5(CH3COO)(DMA)(H2O)]•DMA and ternary soap‐free copolymer (VAc‐AA‐BA) emulsion can be used first for detecting aldehyde vapors.

Vapochromic Behaviors of A Solid‐State Supramolecular Polymer Based on Exo‐Wall Complexation of Perethylated Pillar[5]arene with 1,2,4,5‐Tetracyanobenzene

AbstractThe research for the solid‐state supramolecular polymers with specific functions accelerates the development of supramolecular and materials sciences. Herein, we discover the different complexation modes of perethylated pillar[5]arene (EtP5) with 1,2,4,5‐tetracyanobenzene (TCNB) in various solvents. Driven by charge‐transfer interaction, TCNB is enclosed in the cavity of EtP5 in CHCl3, while TCNB complexes with EtP5 at the exo‐wall of EtP5 in CH2Cl2. This is because the size of CH2Cl2 matches the cavity of EtP5, forcing TCNB to complex with the exo‐wall of EtP5. Furthermore, we fabricate a vapochromic solid‐state supramolecular polymer by exploiting the exo‐wall complexation, which turns from brown to reddish brown or black after adsorption of alkyl aldehyde vapors. The adsorptive nature for alkyl aldehyde vapors comes from the unoccupied cavity of EtP5 based on C−H⋅⋅⋅π interactions. The vapochromic property is attributed to the change of the charge‐transfer interaction caused by molecular rearrangement induced by vapor‐capture in the solid‐state supramolecular polymer.

Vapochromic Behaviors of A Solid-State Supramolecular Polymer Based on Exo-Wall Complexation of Perethylated Pillar[5]arene with 1,2,4,5-Tetracyanobenzene.

The research for the solid-state supramolecular polymers with specific functions accelerates the development of supramolecular and materials sciences. Herein, we discover the different complexation modes of perethylated pillar[5]arene (EtP5) with 1,2,4,5-tetracyanobenzene (TCNB) in various solvents. Driven by charge-transfer interaction, TCNB is enclosed in the cavity of EtP5 in CHCl3 , while TCNB complexes with EtP5 at the exo-wall of EtP5 in CH2 Cl2 . This is because the size of CH2 Cl2 matches the cavity of EtP5, forcing TCNB to complex with the exo-wall of EtP5. Furthermore, we fabricate a vapochromic solid-state supramolecular polymer by exploiting the exo-wall complexation, which turns from brown to reddish brown or black after adsorption of alkyl aldehyde vapors. The adsorptive nature for alkyl aldehyde vapors comes from the unoccupied cavity of EtP5 based on C-H⋅⋅⋅π interactions. The vapochromic property is attributed to the change of the charge-transfer interaction caused by molecular rearrangement induced by vapor-capture in the solid-state supramolecular polymer.

Fabrication of Liquid Crystal Droplet Patterns for Monitoring Aldehyde Vapors.

A sensing method based on the pattern of liquid crystal droplets was developed for detecting and monitoring low levels of organic aldehyde vapors. Exposure of the LC droplet pattern covered with glycine solution to aldehyde vapors induced an optical signal transition from a bright fan shape to a dark cross appearance, as observed by polarized light microscopy. Aldehyde and glycine react at the air/solution interface to form a Schiff-base compound, which controls the orientation of the LCs and induces a change in the optical signals of the LC droplet pattern. The results show that the glycine/LC droplet pattern system is particularly sensitive and selective to aldehydes. In the actual environment, the sensor is exposed to the aldehyde and the signal transition is completed within a few minutes (2-7 min). The LC-based method has the advantages of simple construction, easy operation, convenient data reading, and shows excellent prospects for real-time detection of aldehyde vapors.

Aliphatic Aldehyde Detection and Adsorption by Nonporous Adaptive Pillar[4]arene[1]quinone Crystals with Vapochromic Behavior.

The detection and adsorption of volatile low-molecular-weight aliphatic aldehydes is of significance, owing to their physical volatility, chemical toxicity, and widespread applications in chemical industrial processes. Here, nonporous adaptive pillar[4]arene[1]quinone (EtP4Q1) crystals with vapochromic behavior are used for the volatile aliphatic aldehyde uptake and sensing. When desolvated EtP4Q1 crystals (EtP4Q1α) are exposed to aliphatic aldehydes with different carbon chain lengths, they quantitatively adsorb vapors of these aldehydes, accompanied by different color changes. Crystal structure analyses show that the structure of EtP4Q1 transforms from EtP4Q1α into the corresponding new structures after the adsorption of these aldehydes, which leads to different color changes. The selectivity of EtP4Q1α crystals, which function as both sensors and adsorbents upon exposure to mixed aldehyde vapors, is also explored. Finally, it is demonstrated that EtP4Q1α crystals can be recycled many times without loss of performance.

Measures of odor and lateralization thresholds of acrolein, crotonaldehyde, and hexanal using a novel vapor delivery technique.

IntroductionHumans are exposed to aldehydes in a variety of environmental situations. Aldehydes generally have a strong odor and are highly irritating to the mucous membranes. Knowledge about odor perception and especially irritation potency in humans is thus essential in risk assessment and regulation, e.g. setting occupational exposure limits. However, data on odor and irritation are lacking or limited for several aldehydes. The aim of the study was to determine the odor and lateralization thresholds of some commonly occurring aldehydes. Acrolein and crotonaldehyde where chosen as they are formed when organic material is heated or burned, e.g. during cigarette smoking. n-Hexanal was also included as it is emitted from wood pellets and fibreboard.Material and methodsTo study odor and lateralization thresholds of these aldehydes, a novel, inexpensive olfactometer was designed to enable delivery of reliable and stable test concentrations and thus valid measures of thresholds. The delivery system consists of seven syringe pumps, each connected to a Tedlar bag containing a predefined concentration of the tested aldehyde vapor. To validate the threshold measures, a test-retest was performed with a separate method, namely odor delivery via amber bottles. Twenty healthy naïve individuals were tested.ResultsThe median odor thresholds of acrolein, crotonaldehyde and hexanal were 17, 0.8, and 97 ppb, respectively. No lateralization threshold could be identified for acrolein (highest tested concentration was 2 940 ppb in 5 subjects), whereas the medians were 3 and 390 ppb for the latter two. In addition, odor thresholds for n-hexanal were also determined using two methods where similar results were obtained, suggesting that the olfactometer presentation method is valid.ConclusionWe found olfactory detection and lateralization thresholds (except for acrolein) in alliance with, or lower than, previously reported in naïve subjects. The new olfactometer allows better control of presentations timing and vapor concentration.

Molecularly Imprinted Sol-Gel-Based QCM Sensor Arrays for the Detection and Recognition of Volatile Aldehydes.

The detection and recognition of metabolically derived aldehydes, which have been identified as important products of oxidative stress and biomarkers of cancers; are considered as an effective approach for early cancer detection as well as health status monitoring. Quartz crystal microbalance (QCM) sensor arrays based on molecularly imprinted sol-gel (MISG) materials were developed in this work for highly sensitive detection and highly selective recognition of typical aldehyde vapors including hexanal (HAL); nonanal (NAL) and bezaldehyde (BAL). The MISGs were prepared by a sol-gel procedure using two matrix precursors: tetraethyl orthosilicate (TEOS) and tetrabutoxytitanium (TBOT). Aminopropyltriethoxysilane (APT); diethylaminopropyltrimethoxysilane (EAP) and trimethoxy-phenylsilane (TMP) were added as functional monomers to adjust the imprinting effect of the matrix. Hexanoic acid (HA); nonanoic acid (NA) and benzoic acid (BA) were used as psuedotemplates in view of their analogous structure to the target molecules as well as the strong hydrogen-bonding interaction with the matrix. Totally 13 types of MISGs with different components were prepared and coated on QCM electrodes by spin coating. Their sensing characters towards the three aldehyde vapors with different concentrations were investigated qualitatively. The results demonstrated that the response of individual sensors to each target strongly depended on the matrix precursors; functional monomers and template molecules. An optimization of the 13 MISG materials was carried out based on statistical analysis such as principle component analysis (PCA); multivariate analysis of covariance (MANCOVA) and hierarchical cluster analysis (HCA). The optimized sensor array consisting of five channels showed a high discrimination ability on the aldehyde vapors; which was confirmed by quantitative comparison with a randomly selected array. It was suggested that both the molecularly imprinting (MIP) effect and the matrix effect contributed to the sensitivity and selectivity of the optimized sensor array. The developed MISGs were expected to be promising materials for the detection and recognition of volatile aldehydes contained in exhaled breath or human body odor.

A Family of Metal–Organic Frameworks with a New Chair-Conformation Resorcin[4]arene-Based Ligand: Selective Luminescent Sensing of Amine and Aldehyde Vapors, and Solvent-Mediated Structural Transformations

By utilizing a new chair-conformation resorcin[4]arene-based octacarboxylate ligand, four functional metal–organic frameworks (MOFs), namely, [(CH3)2NH2]4[Cd2(L)]·4H2O (1), [(CH3)2NH2]4[Zn2(L)]·2DMF·6H2O (2), [(CH3)2NH2]4[Co2(L)]·2DMF·4H2O (3), and [(CH3)2NH2]2[Co3(L)(H2O)12] (4) (H8L = 2,8,14,20-tetra-methylphenyl-4,6,10,12,16,18,22,24-octa-carboxymethoxy-resorcin[4]arene and DMF = N,N-dimethylformamide), were solvothermally synthesized and structurally characterized. In 1, each L8– anion bridges eight Cd(II) atoms to give a three-dimensional (3D) (4,8)-connected (46)(412.610.86) framework. In isostructural 2 and 3, each L8– anion links eight adjacent Zn(II) or Co(II) atoms to yield a 3D (4,8)-connected (46)(411.612.85) net. In 4, each L8– anion only bridges four Co(II) atoms by using its four carboxylates each in a monodentate coordination mode to generate an infinite one-dimensional (1D) chain. Remarkably, the highly selective luminescent sensing of amine and aldehyde vapors was studied for 1 and 2 as ...

Aldehyde Complexes with Protonated Peptides in the Gas Phase

This Article presents a study of aldehyde complexes with peptide ions formed by bimolecular collisions in the gas phase. Desolvated ions generated by electrospray ionization are stored within a radio frequency (RF) ion trap and exposed to aldehyde vapor. Mass spectrometry measurements were performed on the resulting aldehyde complexes formed with single amino acids (LysH(+), HisH(+), and ArgH(+)) and polypeptides [Pro(n)-Lys+2H](2+) and [(Gly-Ser)(m)-Lys+2H](2+). These data identify several interesting and unexpected aspects of the aldehyde complex kinetics. It is observed that the formation of stable complexes requires the presence of water vapor. The formation kinetics of aldehyde-peptide complexes exhibits multiexponential time dependence that is modeled by interactions in the presence of structural heterogeneity. Aldehyde binding appears to involve a competition between conformers with unhindered access to protonation sites and conformers with intramolecular solvation of these sites. Proton transfer to the aldehyde ligand is responsible for the loss of the complexes. This is supported by proton affinity calculations and identified by reaction products exhibiting loss of protonation by the parent ion accompanied by the appearance of aldehyde cations.

Cholesteric Liquid Crystals Doped with Dodecylamine for Detecting Aldehyde Vapors

In this paper, we report a study of using cholesteric liquid crystals (CLCs) doped with dodecylamine for detecting aldehyde vapors. CLCs doped with dodecylamine show color change from red to yellow-green upon exposure to 300 ppmv pentyl aldehyde within 60 s. In contrast, no colorimetric response is observed when pure CLCs are used. Characterization by using FT-IR shows that the possible mechanism responsible for the colorimetric response is the formation of an imine bond between dodecylamine and pentyl aldehyde. A new C=N peak at 1670 cm(-1) appears in the spectrum after the exposure to aldehyde vapors. The CLCs doped with dodecylamine show good selectivity for pentyl aldehyde; they do not respond to 200 ppmv pentyl alcohol, pentylamine, acetone, ethanol, and water vapor. This study demonstrates the potential applications of doped CLCs as low-cost and portable gas sensors.

Formaldehyde and acetaldehyde adsorption properties of heat-treated rice husks

Abstract Rice husk (RH) was converted into an adsorbent to remove two types of aldehyde vapor. Japanese RH was carbonized at 250–800 °C in N2 or activated at 875 °C in CO2. The carbonized and activated RHs were exposed to formaldehyde vapor at 1.0 vol. ppm or acetaldehyde vapor at 100 vol. ppm (both in N2 carrier gas) in enclosed 5-L gas-sampling bags. The RH activated at 875 °C showed the fastest decrease in formaldehyde and acetaldehyde concentrations in the bags. The rate of aldehyde adsorption was higher for activated RH than for commercial granular coconut-shell activated carbon (GCSAC), whereas the specific surface area and total pore volume for activated RH (466.9 m2/g and 0.35 cm3/g) were much lower than for GCSAC (1119.7 m2/g and 0.57 cm3/g). The surface basicity of activated RH and RH carbonized at high temperature, attributed to intrinsic inorganic K and Ca compounds, enhanced the surface uptake of aldehydes.

Absorption, fluorescence, and fluorescence excitation spectra of free molecules of indole and its derivatives

We have obtained and analyzed the absorption, fluorescence, and fluorescence excitation spectra of indole vapor, N-acetyl-L-tryptophan vapor, and 3-indole aldehyde vapor. From analysis of the dependence of the fluorescence spectrum of the free indole molecules on the wavelength of the exciting radiation λex, it follows that emission of fluorescence occurs when the molecules undergo a transition from the one electronically excited state 1Lb. The fluorescence spectra of the studied compounds are insignificantly different, suggesting a major role for the indole chromophore in formation of the compounds. The absorption spectrum of N-acetyl-L-tryptophan, in which the group of atoms is added to the indole ring through a-C-C bond, is similar to the spectrum of indole, while the spectrum of 3-indole aldehyde is significantly different from the indole spectrum due to the effect of the C=O group conjugated with the indole ring. The fluorescence excitation spectra are considerably different from the absorption spectra. This is associated with the strong dependence of the quantum yield for the free molecules on λex. Qualitatively, they are mirror-symmetric to the fluorescence spectra of the stodied compounds. Analysis of the data obtained provides a basis for assuming that in the case of free molecules of indole and its derivatives, the 1La absorption in the extreme long-wavelength region of the spectrum does not overlap 1Lb absorption.

籾殻炭のアルデヒド類ガスの吸着効果

Japanese rice husk was converted into an adsorbent for the removal of two types of aldehyde vapors. The rice husks carbonized at 250-800°C in N2 for 1h were exposed to vapors containing 1.0 vol. ppm formaldehyde or 100 vol. ppm acetaldehyde (both N2 carrier) in 5 L-gas sampling bags. Maximum adsorption rates of formaldehyde and acetaldehyde were observed for rice husks carbonized at 800 and 600°C, respectively. The adsorption rates of the aldehydes on the carbonized rice husks were higher than or comparable to those of the commercial granular coconut-shell activated carbon (GCSAC), whereas the specific surface area and the total pore volume of the carbonized rice husks were much lower than that of the GCSAC. The surface basic property of the rice husks carbonized at high temperatures was attributed to the intrinsic inorganic matters of K and Ca, which enhanced an uptake of the aldehydes on their surfaces.

一次消毒の廃止と内視鏡消毒薬の変更に伴う経済効果

In the wards of our hospital, the primary disinfection of medical apparatus had been performed immediately after use. Glutaraldehyde (GA) preparations are used at many medical institutions for disinfection but their use in places with poor ventilation produces high concentrations of aldehyde vapor, which may affect the health of medical staff. In our hospital, primary disinfection in wards was discontinued after the introduction of washer-disinfectors in our central supply department. As a result, disinfection costs in 2001 were about 7 million yen less than the mean annual cost of GA preparations from 1996 to 1999.In the endoscopy room, the disinfectant was changed from a GA preparation to an orthphtaladehyde (PA) preparation. Though this brought about an increase of about 5.3 million yen on the mean annual cost of the GA preparation from 1996 and 1999, since disinfection with PA required less time, more endoscopy examinations could be conducted, resulting in an increase in hospital revenue.

アルデヒド化合物ガス用バイオセンサの研究

Most of aldehyde chemicals such as acetaldehyde, formaldehyde, etc. are defined as Specified Malodor Chemical Substances by the Environment Agency in Japan. In this research, a gas-phase biosensor for aldehyde chemicals was constructed by incorporating an aldehyde dehydrogenase (ALDH) immobilized electrode into a flow reaction cell. The sensor was used to measure acetaldehyde (0.525-20ppm) and formaldehyde (50-2000ppb) in the gas-phase with high selectivity for aldehyde vapor in the presence of other gas-phase chemicals and gave a negligible response to these chemicals.

A Solid Sorbent Personal Air Sampling Method for Aldehydes

A new dynamic solid sorbent personal air sampling method was developed for aldehyde vapors using the 1989 permissible exposure limits of the Occupational Safety and Health Administration and the threshold limit value time-weighted averages of the American Conference of Governmental Industrial Hygienists. Vapors of known concentrations were generated in Tedlar gas bags. Chemisorption through reaction with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) that coated Tenax GC solid sorbent in 200 mg/100 mg front-back sections in a Pyrex™ tube occurred during collection with a personal sampling pump operated at 10 or 50 mL/min over four to eight hours. The O-oxime derivative was desorbed quantitatively with Optima™ hexane, and an aliquot injected for gas chromatographic analysis on a nonpolar capillary column with mass spectrometric detection. Humidity had no effect on the recoveries (>70%) of valeraldehyde, acrolein, acetaldehyde, furfural, and crotonaldehyde vapors. Coefficients of variati...