Formaldehyde Derivatization: An Unexpected Side Reaction During Filter-Aided Sample Preparation.

The filter-aided sample preparation (FASP) method has been commonly used for proteomic sample preparation due to its high efficiency in removing impurities. Herein, we report an overlooked +12 Da side modification during FASP method using Microcon spin filters. We confirmed that the side modification is caused by formaldehyde released from the spin filter and found that the side modification leads to 10.5% and 9.5% loss in proteome-level peptide and protein identification, respectively. We evaluated different pretreatment procedures to reduce the side reaction. Furthermore, on the basis of the evaluation results of different brands of spin filters, we recommend Nanosep spin filters for different proteomic studies, especially for amine-labeling proteomic studies. Our results would benefit researchers employing the spin filters to improve their results and also help spin filter manufacturers to improve the product quality. Data are available via ProteomeXchange with identifier PXD018737.

A simple pyrene-based fluorescent probe for highly selective detection of formaldehyde and its application in live-cell imaging.

A novel and simple pyrene-based fluorescent probe (B1) was synthesized and used for the detection of formaldehyde (FA). When B1 was added to FA in CH3CH2OH/HEPES (10 mM, pH = 7.4, 1:99, v/v) solution, the solution system strongly enhanced the fluorescence. Over various small molecular species, probe B1 showed high sensitivity and selectivity for detecting FA, with a low limit of detection (0.107 µM). Furthermore, probe B1 was successfully applied for visualizing FA in human embryonic kidney (HEK293T) cells, demonstrating its value of application in living biomedical samples.

Formaldehyde Hemiacetal Sampling, Recovery, and Quantification from Electronic Cigarette Aerosols.

The electronic cigarette solvents propylene glycol and glycerol are known to produce toxic byproducts such as formaldehyde, acetaldehyde and acrolein. However, the aerosol toxin yield depends upon a variety of chemical and physical variables. The formaldehyde hemiacetals derived from these solvents were reported as major electronic cigarette aerosol components by us in 2015. In the study described herein, the formaldehyde hemiacetals were found at higher levels than those of free formaldehyde via an orthogonal sample collection protocol. In addition, the common aldehyde collection methods for electronic cigarettes, such as impingers and sorbent tubes containing DNPH, significantly underestimate the levels of formaldehyde. The reason for this is that formaldehyde hemiacetals follow other reaction pathways, such as the formation of a less reactive full cyclic acetal catalyzed by the acidity of the DNPH solution and the silica. We found that formaldehyde hemiacetals are a considerable fraction of the total formaldehyde produced in electronic cigarette that cannot be determined accurately by DNPH derivatization methods. Although the health effects of the hemiacetals are not yet known, they warrant further investigation.

Avaliação qualitativa e quantitativa de formaldeído em produtos cosméticos para alisamento capilar / Qualitative and quantitative evaluation of formaldehyde in cosmetic products for hair straightening

O formaldeído, comercializado em solução aquosa a 37% (p/p), é um líquido incolor com odor forte e irritante. A presença deste agente cancerígeno em cremes cosméticos resulta em graves riscos à saúde tais como irritação, queimaduras na pele, ferimentos nas vias respiratórias e danos irreversíveis aos olhos e cabelos provocados pela inalação e contato com o produto. Seu uso foi permitido em concentração ≤ 0,2% (p/p) como conservante pela Agência Nacional de Vigilância Sanitária (ANVISA; Brasil, 2001) até junho de 2014, e a substância era adicionada a produtos cosméticos utilizados em escovas progressivas com a finalidade de alisar os cabelos. Diante dos riscos verificados com a utilização da substância, objetivou-se determinar qualitativa e quantitativamente, a incidência deste aldeído em produtos para alisamento capilar, a fim de estimar a concentração que os profissionais e usuários estão expostos, para garantir sua segurança. Observouse que 84,6% das amostras analisadas apresentaram alguma irregularidade, sendo que 61,5% das amostras analisadas apresentaram maior quantidade de formaldeído do que era permitido pela legislação (Brasil, 2001) como conservante e 53,8% apresentou mais de 10 vezes o percentual permitido, concentração irritante para a população em geral. Tendo em vista a gravidade dos dados apresentados, é necessária uma rígida fiscalização da qualidade dos alisantes capilares e estratégias de conscientização sobre riscos à saúde do contato com a substância.

Formaldehyde marketed in a 37% (w/w) aqueous solution is a colorless liquid with a strong irritating odor. The presence of this carcinogen in cosmetics creams results in serious health risks, such as irritation, skin burns, airway injury and irreversible damage to the eyes and hair caused by inhalation and contact with the product. Although its use was allowed up to a concentration of 0.2% (w/w) as a preservative by Brazilian Health Surveillance Agency (ANVISA; Brazil, 2001) until June 2014, the substance is added to cosmetic products used in progressive brushes in order to straighten hair. Given the risks seen with the use of the substance, the objective was to determine qualitatively and quantitatively this aldehyde in products for hair straightening in order to estimate the concentration that professionals involved and users are exposed to ensure their safety. It was observed that 84.6% of the samples showed some irregularity, being that 61.5% of the samples have a higher amount of formaldehyde than allowed by law (Brazil, 2001) as preservative and 53.8% had more than 10 times the allowable percentage, irritating concentration for the general population. Considering the severity of the data presented, it is need a strict quality supervision hair straightening products and strategies to increase awareness about health risks from contact with the substance.

Chemistry of phosphorylated formaldehyde derivatives. Part I.

The underinvestigated derivatives of unstable phosphorylated formaldehyde acetals and some of the structurally related compounds, such as thioacetals, aminonitriles, aminomethylphosphinoyl compounds, are considered. Separately considered are halogen aminals of phosphorylated formaldehyde, acetals of phosphorylated formaldehyde of H-phosphinate-type and a phosphorylated gem-diol of formaldehyde. Synthetic methods, chemical properties and examples of practical applications are given.

Homogeneous and heterogeneous noncovalent dimers of formaldehyde and thioformaldehyde: structures, energetics, and vibrational frequencies.

This work provides the first characterization of five stationary points of the homogeneous thioformaldehyde dimer, (CH2S)2, and seven stationary points of the heterogeneous formaldehyde/thioformaldehyde dimer, CH2O/CH2S, with correlated ab initio electronic structure methods. Full geometry optimizations and corresponding harmonic vibrational frequencies were computed with second-order Møller-Plesset perturbation theory (MP2) and 13 different density functionals in conjunction with triple-ζ basis sets augmented with diffuse and multiple sets of polarization functions. The MP2 results indicate that the three stationary points of (CH2S)2 and four of CH2O/CH2S are minima, in contrast to two stationary points of the formaldehyde dimer, (CH2O)2. Single-point energies were also computed using the explicitly correlated MP2-F12 and CCSD(T)-F12 methods and basis sets as large as heavy-aug-cc-pVTZ. The (CH2O)2 and CH2O/CH2S MP2 and MP2-F12 binding energies deviated from the CCSD(T)-F12 binding energies by no more than 0.2 and 0.4 kcal mol(-1), respectively. The (CH2O)2 and CH2O/CH2S global minimum is the same at every level of theory. However, the MP2 methods overbind (CH2S)2 by as much as 1.1 kcal mol(-1), effectively altering the energetic ordering of the thioformaldehyde dimer minima relative to the CCSD(T)-F12 energies. The CCSD(T)-F12 binding energies of the (CH2O)2 and CH2O/CH2S stationary points are quite similar, with the former ranging from around -2.4 to -4.6 kcal mol(-1) and the latter from about -1.1 to -4.4 kcal mol(-1). Corresponding (CH2S)2 stationary points have appreciably smaller CCSD(T)-F12 binding energies ranging from ca. -1.1 to -3.4 kcal mol(-1). The vibrational frequency shifts upon dimerization are also reported for each minimum on the MP2 potential energy surfaces.

The fabrication of porous N-doped carbon from widely available urea formaldehyde resin for carbon dioxide adsorption.

N-doped carbon material constitutes abundant of micropores and basic nitrogen species that have potential implementation for CO2 capture. In this paper, porous carbon material with high nitrogen content was simply fabricated by carbonizing low cost and widely available urea formaldehyde resin, and then followed by KOH activation. CO2 capture experiment showed high adsorption capacity of 3.21 mmol g(-1) at 25 °C under 1 atm for UFCA-2-600. XRD, SEM, XPS and FT-IR analysis confirmed that a graphitic-like structure was retained even after high temperature carbonization and strong base activation. Textural property analysis revealed that narrow micropores, especially below 0.8 nm, were effective for CO2 adsorption by physical adsorption mechanism. Chemical evolved investigation revealed that graphitic-like embedded basic nitrogen groups are generated from bridged and terminal amines of urea formaldehyde resin from thermal carbonization and KOH activation treatment, which is responsible for the enrichment of CO2 capacity by chemical adsorption mechanism. The relationship between CO2 adsorption capacity and pore size or basic N species was also studied, which turned out that both of them played crucial role by physical and chemical adsorption mechanism, respectively.

Complexation of n SO2 molecules (n = 1, 2, 3) with formaldehyde and thioformaldehyde.

Ab initio and density functional theory calculations are used to examine complexes formed between H2CO and H2CS with 1, 2, and 3 molecules of SO2. The nature of the interactions is probed by a variety of means, including electrostatic potentials, natural bond orbital, atoms in molecules, energy decomposition, and electron density redistribution maps. The dimers are relatively strongly bound, with interaction energies exceeding 5 kcal/mol. The structures are cyclic, containing both a O/S⋯S chalcogen bond and a CH⋯O H-bond. Addition of a second SO2 molecule leads to a variety of heterotrimer structures, most of which resemble the original dimer, where the second SO2 molecule engages in a chalcogen bond with the first SO2, and a C⋯O attraction with the H2CX. Some cooperativity is apparent in the trimers and tetramers, with an attractive three-body interaction energy and shortened intermolecular distances.

Journey through the potential energy surfaces for the isomerization and decomposition reactions of the telluroformaldehyde analogues: H2A═Te and HFA═Te (A = C, Si, and Ge).

The unavailability of monomeric heavy ketone analogues has been ascribed to the evanescence of the very reactive A═E double bond (A and E are the heavier group 14 and group 16 elements, respectively). Can the isolation of any of the monomeric telluro-ketones be assisted by an energetic favorability on its potential energy surface (PES)? In this light, the reaction pathways for the isomerization and decomposition reactions of H2A═Te and HFA═Te (A = C, Si, and Ge) molecules on their singlet state PES have been studied using second-order Møller-Plesset perturbation theory (MP2). The barrier heights reported suggest that telluroformaldehyde, silanetellone, and germatellone are kinetically more resistant to unimolecular reactions than the corresponding lighter chalcogen analogues. However, upon replacing a hydrogen atom by fluorine, the barrier heights of most of the isomerization and decomposition reactions are lowered. Among the unimolecular reactions studied for the H2A═Te and HFA═Te (A = C, Si, and Ge) molecules, the decomposition of cis-FGeTeH into HF and GeTe is found to be the most facile reaction, with a barrier height of only 4.6 kcal/mol. We also predict the ground state telluro-ketones to be viable molecules, as they have no imaginary vibrational frequencies and their lowest vibrational frequencies are always >100 cm(-1). In view of the scarcity of information on the chemistry of the mentioned telluro-ketones, the molecular parameters of various isomers and decomposition products have been reported, and should be useful for future experimental investigations.

Dual organocatalytic activation of isatins and formaldehyde tert-butyl hydrazone: asymmetric synthesis of functionalized 3-hydroxy-2-oxindoles.

Two is better than one! Dual activation of isatins and formaldehyde tert-butyl hydrazone by 2,2'-diamino-1,1'-binaphthalene (BINAM)-derived bis(ureas) is the key to achieve high reactivity and excellent enantioselectivities in the synthesis of azo- and azoxy-functionalized 3-hydroxy-2-oxindoles (see scheme).

A highly selective fluorescent probe for Al3+ based on 4-aminoantipyrine.

A novel and simple Schiff base based on 2-pyridine formaldehyde and 4-aminoantipyrine was synthesized and characterized as a fluorescent probe. In the presence of Al(3+), the fluorescent intensity has a dramatic enhancement over other examined metal ions in aqueous solution. The method of Job's plot indicated the formation of 1:1 complex between probe and Al(3+), and the possible binding mode of the system was also proposed. Moreover, other examined metal ions had no effect on the detection of Al(3+).

Formalehyde in personal care products.

Personal care products reported to cause allergic contact dermatitis from the presence of formaldehyde need to be re-examined in light of recent chemical developments in our understanding of the film former, toluene sulfonamide formaldehyde resin, the preservatives diazolidinyl urea and imidazolidinyl urea, and formalin. This paper will elucidate these chemistries as well as review how formaldehyde is used in personal care products in raw materials and formaldehyde donor preservatives.

Forensic scatology: preliminary experimental study of the preparation and potential for identification of captive carnivore scat.

Carnivore scats recovered from animal attack and/or scavenging contexts frequently contain forensic evidence such as human bone fragments. Forensic cases with carnivore involvement are increasingly prevalent, necessitating a methodology for the recovery and analysis of scat evidence. This study proposes a method for the safe preparation of carnivore scat, recovery of bone inclusions, and quantification and comparison of scat variables. Fourteen scats (lion, jaguar, lynx, wolf, and coyote) were prepared with sodium-acetate-formalin fixative; analytical variables included carnivore individual, species, body size, and taxonomic family. Scat variables, particularly bone fragment inclusions, were found to vary among carnivore individuals, families, species, and sizes. The methods in this study facilitate safe scat processing, the complete recovery of digested evidence, and the preliminary identification of involved animals. This research demonstrates that scat collected from forensic contexts can yield valuable information concerning both the victim and the carnivore involved.

Abilities of different electron donors (D) to engage in a P···D noncovalent interaction.

Previous work has documented the ability of the P atom to form a direct attractive noncovalent interaction with a N atom, based in large measure on the charge transfer from the N lone pair into the σ* antibonding orbital of the P-H that is turned away from the N atom. The present work considers whether other atoms, namely, O and S, can also participate as electron donors, and in which bonding environments. Also considered are the π-systems of multiply bonded C atoms. Unlike an earlier observation that the interaction is unaffected by the nature of the electron-acceptor atom, there is strong sensitivity to the donor. The P···D binding energy diminishes in the order D = NH(3) > H(2)CO > H(2)CS > H(2)O > H(2)S, different from the patterns observed in both H and halogen bonds. The P···D interactions are comparable to, and in some cases stronger than, the analogous H-bonds formed by HOH as proton donor. The carbon π systems form surprisingly strong P···D complexes, augmented by the back-donation from the P lone pair to the C-C π* antibond, which surpass the strengths of H-bonds, even some with HF as proton donor.

Computational study of the properties and reactions of small molecules containing O, S, and Se.

The reactions and properties of a series of chalcogen-containing compounds (CH(3))(2)X and (CH(3))(2)C═X, where X = O, S, and Se, were studied computationally at the CBS-QB3 level to examine the differences among these molecules. The reactions and properties investigated include the double bond dissociation energy, the ionization potential, the interaction energies with a series of acids including a proton, CH(3)(+), Li(+), MeLi, and MeOH, and the enolization energies of the (CH(3))(2)C═X species. The effect of substituting the O of acetamide with S or Se also was studied. The changes that result from these reactions were examined via changes in structure and changes in charge distribution using the Hirshfeld charges.

Formaldehyde: integrating dosimetry, cytotoxicity, and genomics to understand dose-dependent transitions for an endogenous compound.

Formaldehyde (FA), an endogenous cellular aldehyde, is a rat nasal carcinogen. In this study, concentration and exposure duration transitions in FA mode of action (MOA) were examined with pharmacokinetic (PK) modeling for tissue formaldehyde acetal (FAcetal) and glutathione (GSH) and with histopathology and gene expression in nasal epithelium from rats exposed to 0, 0.7, 2, 6, 10, or 15 ppm FA 6 h/day for 1, 4, or 13 weeks. Patterns of gene expression varied with concentration and duration. At 2 ppm, sensitive response genes (SRGs)-associated with cellular stress, thiol transport/reduction, inflammation, and cell proliferation-were upregulated at all exposure durations. At 6 ppm and greater, gene expression changes showed enrichment of pathways involved in cell cycle, DNA repair, and apoptosis. ERBB, EGFR, WNT, TGF-ß, Hedgehog, and Notch signaling were also enriched. Benchmark doses for significantly enriched pathways were lowest at 13 weeks. Transcriptional and histological changes at 6 ppm and greater corresponded to dose ranges in which the PK model predicted significant reductions in free GSH and increases in FAcetal. Genomic changes at 0.7-2 ppm likely represent changes in extracellular FAcetal and GSH. DNA replication stress, enhanced proliferation, squamous metaplasia, and stem cell niche activation appear to be associated with FA carcinogenesis. Dose dependencies in MOA, high background FAcetal, and nonlinear FAcetal/GSH tissue kinetics indicate that FA concentrations below 1 or 2 ppm would not increase risk of cancer in the nose or any other tissue or affect FA homeostasis within epithelial cells.

[Glyoxal: a possible polyvalent substitute for formaldehyde in pathology?]. / Le glyoxal : un possible substitut polyvalent du formaldéhyde en anatomie pathologique ?

The quest for formaldehyde substitutes is motivated by two fundamental developments: the OSHA regulation standard declaring it hazardous and advocating its substitution with less dangerous chemicals and the fact that formalin is a poor preserver of nucleic acids. Among the non-alcoholic formalin substitute, glyoxal has been hailed as the best alternative. In this work, we showed that glyoxal-containing fixatives are not plausible polyvalent substitution options.

Efecto antinociceptivo de Critoniella acuminata, Physalis peruviana y Salvia rubescens / Antinociceptive effect of Critoniella acuminata, Physalis peruviana and Salvia rubescens

Se evaluó el efecto antinociceptivo de extractos, fracciones y compuestos de Critoniella acuminata, Physalis peruviana y Salvia rubescens mediante los métodos de placa caliente, contorsiones abdominales inducidas por ácido acético y ensayo de la formalina. La fracción de Critoniella acuminata en dosis de 100 mg/kg p.o. presentó actividad antinociceptiva al aumentar el tiempo de reacción del animal ante la aplicación de un estímulo térmico (método de la placa caliente), mientras que la fracción de Physalis peruviana, en una dosis de 100 mg/kg p. o., ejerce un efecto antinociceptivo frente al dolor generado por estímulos químicos (dolor visceral agudo) al inhibir en un 40 por ciento las contorsiones abdominales inducidas por ácido acético y el número de lamidos durante la fase ii (dolor inflamatorio agudo) en el ensayo de formalina. Estos resultados sugieren que la ayapina y la fracción de Physalis peruviana estudiadas tienen actividad antinociceptiva, con posibles mecanismos de tipo opioide y aine, respectivamente.

The antinociceptive effect of extracts, fractions and compounds of Critoniella acuminata, Physalis peruviana and Salvia rubescens were evaluated by the follow methods: Hot Plate test, acetic acid induced abdominal writhing and Formalin test. The fraction of Critoniella acuminata at doses of 100mg/kg p.o. exhibited antinociceptive effect in the hot plate test; while Physalis peruviana fraction at doses of 100 mg/kg p.o., showed an antinociceptive effect against the pain chemically induced. This fraction produced 40 percent inhibition of the acetic acid induced writhing (acute visceral nociception) and the licks during phase ii (acute inflammatory nociception)of the formalin test. The findings of this experimental study suggest that fractions of Critoniella acuminata and Physalis peruviana possess antinociceptive activity with opioid and nsaid-like mechanisms respectively.

Decreasing sulfide generation in sewage by dosing formaldehyde and its derivatives under anaerobic conditions.

Hydrogen sulfide emission in sewers is associated with toxicity, corrosion, odour nuisance and high costs. In this study, a new method to inhibit sulfide generation by means of formaldehyde and its derivatives has been evaluated under anaerobic conditions. The possible impact of formaldehyde on an activated sludge system and an appraisal of the economic aspects are presented as well. A dosage of 19 mg L(-1) formaldehyde resulted in a decrease of the sulfide production of 90%. Dosing of 32 mg L(-1) paraformaldehyde and addition of 111 mg L(-1) ureaformaldehyde were not sufficient to inhibit the sulfide generation in sewage to the same extent. The impacts of 19 mg L(-1) formaldehyde on activated sludge, in terms of COD removal, nitrification rate and oxygen uptake rates, were negligible. This suggests that formaldehyde dosage is a feasible technique to abate the sulfide problem in sewers.