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PubMed2005

Mechanism for the gas-phase reaction between formaldehyde and hydroperoxyl radical. A theoretical study.

We present a high-level theoretical study on the gas-phase reaction between formaldehyde and hydroperoxyl radical carried out using the DFT-B3LYP, QCISD, and CCSD(T) theoretical approaches in connection with the 6-311+G(d,p), 6-311+G(2df,2p), and aug-cc-pVTZ basis sets. The most favorable reaction path begins with the formation of a pre-reactive complex and produces the peroxy radical CH(2)(OO)OH in a process that is computed to be exothermic by 16.8 kcal/mol. This reaction involves a process in which the oxygen terminal of the HO(2) moiety adds to the carbon of formaldehyde, and, simultaneously, the hydrogen of the hydroperoxyl group is transferred to the oxygen of the carbonyl in a proton-coupled electron-transfer mechanism. Our calculations show that this transition state lies below the sum of the energy of the reactants, and we computed a rate constant at 300 K of 9.29 x 10(-14) cm(3) molecule(-1) s(-1), which is in good agreement with the experimental results. Also of interest in combustion chemistry, we studied the hydrogen abstraction process by HO(2), the result of which is the formation of HCO + H(2)O(2). We found two reaction paths with activation enthalpies close to 12 kcal/mol. For this process, we computed a rate constant of 1.48 x 10(-16) cm(3) molecule(-1) s(-1) at 700 K, which also agrees quite well with experimental results.

Algorithms↗
PubMed2006

Absorption cross sections of formaldehyde at wavelengths from 300 to 340 nm at 294 and 245 K.

Absorption cross sections for the A1A2-X1A1 electronic transition of formaldehyde have been measured by ultraviolet (UV) laser absorption spectroscopy in the tropospherically significant wavelength range 300-340 nm, over which HCHO is photochemically active. Absorption cross sections are reported at two temperatures, 294 and 245 K and at a spectral resolution of 0.0035 nm (0.35 cm-1). At this resolution, greater peak absorption cross sections are obtained for many of the sharp spectral features than were previously reported. To simulate atmospheric conditions in the troposphere, the effects of adding a pressure of nitrogen of up to 500 Torr and of reduced sample temperature were investigated. The overall magnitudes of peak absorption cross sections are largely unaffected by the added pressure of nitrogen, but a modest degree of pressure broadening (0.2-0.3 cm-1 atm-1) is evident in the line shapes. Computer simulations of spectra have been optimized by comparison with wavelength-dependent formaldehyde absorption cross sections for each major vibronic band in the chosen wavelength range. Experimental and computer simulated spectra at 294 and 245 K are compared to test the reliability of the computer simulations for quantification of the effects of temperature on absorption cross sections. All experimental absorption cross section data and tables of input parameters for spectral simulations are available as Supporting Information.

Atmosphere↗
PubMed2000

Identification of fluorescent 2'-deoxyadenosine adducts formed in reactions of conjugates of malonaldehyde and acetaldehyde, and of malonaldehyde and formaldehyde.

2'-Deoxyadenosine was reacted with malonaldehyde in the presence of formaldehyde or acetaldehyde. The reactions were carried out at 37 degrees C in aqueous solution at acidic conditions. The reaction mixtures were analyzed by HPLC. In both reactions, two major products were formed. The reaction products were isolated and purified by C18 chromatography, and their structures were characterized by UV absorbance, fluorescence emission, (1)H and (13)C NMR spectroscopy, and mass spectrometry. The reaction products isolated from the mixture containing formaldehyde, malonaldehyde, and deoxyadenosine were identified as 3-(2'-deoxy-beta-D-ribofuranosyl)-7H-8-formyl[2,1-i]pyrimidopurine (M(1)FA-dA) and 9-(2'-deoxy-beta-D-ribofuranosyl)-6-(3,5-diformyl-1, 4-dihydro-1-pyridyl)purine (M(2)FA-dA). In the reaction mixture consisting of acetaldehyde, malonaldehyde, and deoxyadenosine, the identities of the products were determined to be 3-(2'-deoxy-beta-D-ribofuranosyl)-7-methyl-8-formyl[2, 1-i]pyrimidopurine (M(1)AA-dA) and 9-(2'-deoxy-beta-D-ribofuranosyl)-6-(3,5-diformyl-4-methyl-1, 4-dihydro-1-pyridyl)purine (M(2)AA-dA). The yields of the compounds were 1.8 and 0.7% for M(1)FA-dA and M(2)FA-dA, respectively, and 6.8 and 10% for M(1)AA-dA and M(2)AA-dA, respectively. All compounds exhibited marked fluorescent properties. These findings show that in addition to direct reaction of a specific aldehyde with 2'-deoxyadenosine, aldehyde conjugates also may react with the base. Although three of the adducts (M(1)FA-dA, M(2)FA-dA, and M(1)AA-dA) could not be detected in reactions carried out under neutral conditions, the possibility that trace amounts of the adducts may be formed under physiological conditions cannot be ruled out. Therefore, conjugate adducts must be considered in work that aims at clarifying the mechanism of aldehyde genotoxicity.

Acetaldehyde↗
PubMed1998

Prebiotic chemistry of phosphonic acids: products derived from phosphonoacetaldehyde in the presence of formaldehyde.

Phosphonoacetaldehyde (PAL), a phosphonic acid analogue of glycolaldehyde phosphate, reacts in the presence of formaldehyde under mildly basic conditions to produce several new products. The reaction proceeds in two stages: a fast aldol condensation of formaldehyde with PAL, and a slower reaction to produce products containing two phosphonic acid groups. We report on the derivatization, isolation by means of HPLC and characterization of these compounds. One of the products is of potential interest as a building block for a prebiotic informational polymer.

Acetaldehyde↗
PubMed2001

Formaldehyde and methanol biodegradation with the methylotrophic yeast Hansenula polymorpha. An application to real wastewater treatment.

The application of methylotrophic yeast Hansenula polymorpha to the treatment of methanol and formaldehydecontaining wastewater was experimentally verified. A variety of real wastewater samples originating from chemical industry effluent were examined. The yeast cell culture could grow in the wastewater environment, revealing low trophic requirements and a very high adaptation potential to poor cultivation conditions. The proliferation of cells was accompanied by a concomitant xenobiotic biodegradation. Grown, preadapted cellular suspension at a density of about 1 x 10(7) cells/ml proved to be able to utilize formaldehyde present in wastewater at concentrations up to 1750 mg/l, levels toxic to most microorganisms. The biological waste treatment method presented shows the enhanced potential by means of specific enzymatic activities of monocarbonic compound oxidations through methylotrophic pathway reactions. The need to obtain mutants highly resistant to formaldehyde has also been rationalized.

Biodegradation, Environmental↗
PubMed1987

Phenolic cyclization of epinephrine, metaproterenol, metaraminol, phenylephrine, and terbutaline with formaldehyde.

An exploratory study of the rates of cyclization of the title compounds, all 3-hydroxyphenalkanolamines, with formaldehyde to 1,2,3,4-tetrahydroisoquinolines (THIQs) was performed using high-performance liquid chromatographic (HPLC) methods. Reactions occur quantitatively and practically instantaneously at room temperature and neutral pH; thus, rates were measured at acid pH. Cyclization occurs ortho or para to the 3-phenolic function, so that all but the 3,5-dihydroxyphenyl derivatives, metaproterenol and terbutaline, gave two THIQs. Terbutaline reacted significantly slower than the other compounds. Formaldehyde occurs in pharmaceutical systems and it serves as a model for other aldehydes that occur in sugars and flavors. The pharmaceutical implications of the reaction are discussed.

Cyclization↗
PubMed1998

Increase of formation of methylamine and formaldehyde in vivo after administration of nicotine and the potential cytotoxicity.

Methylamine is a constituent of cigarette smoke and the major end product of nicotine metabolism. Smoking or nicotine can induce the release of adrenaline, which is in turn deaminated by monoamine oxidase, also producing methylamine. We found that the urinary level of methylamine was significantly elevated following administration of nicotine (25 mg/Kg, i.p.). Semicarbazide-sensitive amine oxidase (SSAO) inhibitors further increased the excretion of methylamine induced by nicotine. Following administration of L-(-)-[N-methyl-3H]nicotine long-lasting irreversible radioactive adducts were detected in different mouse tissues and such adduct formation could be blocked by selective SSAO inhibitors. These adducts are probably cross-linked oligoprotein complexes cross-linked by formaldehyde. The findings support the idea that nicotine can enhance SSAO/methylamine-mediated increase of formaldehyde and oxidative stress and this could in part contribute the adverse effect of health associated with smoking.

Allyl Compounds↗
PubMed1999

A possible evolutionary role of formaldehyde.

Formaldehyde is a compound which is believed to have had a role in evolutionary processes. On the other hand, the (methyl)glyoxalase pathway is a route being present in all biological organisms whereas its function has not yet been recognized in the biochemical machinery. In this article it is raised that (methyl)glyoxalase path might have functioned as a bridge between formose and archaic reductive citric acid cycles in surface metabolists at the early stage of evolution. According to the theory, formaldehyde was essential for the mentioned system as a raw molecule. Based on thermodynamic calculations a simple way of regulation is also shown. The simplicity of the theory may be in a good agreement with and an explanation of why the (methyl)glyoxalase system is of ubiquitous nature.

Citric Acid Cycle↗
PubMed1998

Development of an automated measurement system using a diffusion scrubber and high-performance liquid chromatography for the monitoring of formaldehyde and acetaldehyde in automotive exhaust gas.

An automated measurement system for monitoring formaldehyde (HCHO) and acetaldehyde (CH3CHO) in automotive exhaust gas by using a diffusion scrubber in combination with high-performance liquid chromatography (HPLC) was developed. HCHO and CH3CHO are effectively collected by the diffusion scrubber, which consists of a hydrophobic porous PTFE tube disposed concentrically within a Pyrex-glass tube and a scrubbing solution. 2,4-Dinitrophenylhydrazine is used as the scrubbing solution for trapping HCHO and CH3CHO, which are derivatized to formaldehyde 2,4-dinitrophenylhydrazone (DNPH-HCHO) and acetaldehyde 2,4-dinitrophenylhydrazone (DNPH-CH3CHO), respectively, with phosphoric acid as an acid catalyst. After the collection of the gas sample, the sample solution in the diffusion scrubber is injected into the HPLC system and DNPH-HCHO and DNPH-CH3CHO are separated and determined. All measurement operations are sequenced by a programmable controller and an automated continuous measurement can be performed at 10 min intervals. The collection efficiencies of HCHO and CH3CHO were higher than 97% at a gas flow rate of 0.21 min-1. The detection limit (3 sigma of the blank value) was 0.001 ppm v/v for HCHO and CH3CHO for a 1.61 gas sample volume. No interference of co-existing nitrogen dioxide (NO2) in the collection of HCHO and CH3CHO was observed. The average concentration of HCHO in the exhaust gas from methanol-fueled vehicles was 77.3 ppm v/v (n = 5) in the cold-phase mode when engines were first started. In the hot-phase mode, the average concentration of HCHO was 3.3 ppm v/v (n = 15). The concentrations of HCHO measured by this automated measurement system were in good agreement with those obtained using the impinger-HPLC method.

Acetaldehyde↗
PubMed1999

Determination of formaldehyde in liquid, solid and semisolid pharmaceuticals and cosmetics by flow injection-pervaporation.

A spectrophotometric method is proposed for the determination of formaldehyde in liquid, solid and semisolid cosmetic and pharmaceutical samples, employing, for the first time in this field, the coupling of a continuous flow configuration to a pervaporation unit. The method is based on the reaction of the analyte with pararosaniline in acidic medium and subsequent formation of a coloured product (alkylsulfonic acid chromophore) with sodium sulfite, which was monitored spectrophotometrically. The method was applied to samples in which the formaldehyde content is regulated by law.

Cosmetics↗
PubMed1989

Determination of formaldehyde and acetaldehyde in mainstream cigarette smoke by high-performance liquid chromatography.

A method is described for the determination of formaldehyde and acetaldehyde in mainstream cigarette smoke. This involved the collection and reaction of the aldehydes with 2,4-dinitrophenylhydrazine in aqueous acetonitrile. The high-performance liquid chromatographic separation and measurement of the various components directly in this reaction solution eliminated the need for a clean-up stage. Cigarette yields of greater than 5 micrograms of formaldehyde and 50 micrograms of acetaldehyde could be determined to estimated relative standard deviations of 0.07 and 0.05, respectively.

Acetaldehyde↗
PubMed2000

Colorimetric determination of formaldehyde in air using a hanging drop of chromotropic acid.

A simple and sensitive method to determine parts per billion (ppb) of atmospheric formaldehyde in situ, using chromotropic acid, is described. A colorimetric sensor, coupled to a droplet of 15.5 microL chromotropic acid, was constructed and used to sample and quantify formaldehyde. The sensor was set up with two optical fibers, a light emitting diode (LED) and two photodiodes. The reference and transmitted light were measured by a photodetection arrangement that converts the signals into units of absorbance. Air was sampled around the chromotropic acid droplet. A purple product was formed and measured after the sampling terminated (typically 7 min). The response is proportional to the sampling period, analyte concentration and sample flow rate. The detection limit is approximately 2 ppb and can be improved by using longer sampling times and/or a sampling flow rate higher than that used in this work, 200 mL min-1. The present technique affords a simple, inexpensive near real-time measurement with very little reagent consumption. The method is selective and highly sensitive. This sensor could be used either for outdoor or indoor atmospheres.

Air Pollution, Indoor↗
PubMed1968

A spectrophotometric study of the denaturation of deoxyribonucleic acid in the presence of urea or formaldehyde and its relevance to the secondary structure of single-stranded polynucleotides.

1. The thermal denaturation of DNA from rat liver was studied spectrophotometrically. In sodium phosphate buffers denaturation led to a single-stranded form having, at 25 degrees , about 25% of the hypochromism of the intact double helix. 2. The hypochromism of the denatured form was the same in 1mm- as in 10mm-sodium phosphate buffer and was scarcely affected by reaction with formaldehyde. The hypochromism was decreased by about 40% in the presence of 8m-urea. 3. The hypochromism of denatured DNA at low ionic strengths was about the same as that of fragments of reticulocyte ribosomal RNA that were too short to form double-helical secondary structure and about the same as that of RNA after reaction with formaldehyde. 4. The spectrum of DNA was slightly affected by the presence of 8m-urea or 4m-guanidinium chloride. The differences in the spectrum of the native and denatured forms of DNA in 0.1m-sodium phosphate buffer, in 8m-urea-10mm-sodium phosphate buffer and in 4m-guanidinium chloride-10mm-sodium phosphate buffer, pH7.6, were similar but not identical. 5. Denatured rat liver DNA appears to have no double-helical character at 25 degrees in 10mm-sodium phosphate buffer, pH7.6; increasing the buffer concentration to 0.1m leads to a more compact form in which about 40% of the residues form base pairs.

Animals↗
PubMed1999

Polymerase chain reaction detection of Puumala virus RNA in formaldehyde-fixed biopsy material.

BACKGROUND: Infections with hantaviruses, mainly Clethrionomys-derived Puumala viruses, are known causes of acute renal failure [hemorrhagic fever with renal syndrome (HFRS)] in western Europe. Laboratory diagnosis is primarily based on serology. At the time of clinical symptoms, viral RNA can hardly be detected in the blood or urine, indicating that polymerase chain reaction (PCR) is of little diagnostic value for these infections. Biopsy material is usually formaldehyde-fixed and, thus, regarded as poor quality for PCR applications. The aim of this study was to establish a technique to retrieve such material for laboratory diagnostic. METHODS: Formaldehyde-fixed, paraffin-embedded kidney biopsies of 14 patients with renal failure either clinically suspected for HFRS (7 cases) or caused by unknown (2 cases) or known other causes (drugs, sarcoidosis; 5 cases) were histologically investigated. An established S segment-specific PCR assay was applied to RNA isolated from the biopsies, and amplification products were verified by direct sequence determination. RESULTS: Investigations revealed a typical histopathological appearance for hantavirus infections in all seven suspected HFRS cases and one case of unknown cause. With five of the suspected HFRS cases, hantavirus-specific RNA was detected. Sequence comparison revealed a close relationship to corresponding nucleoproteins of known Puumala viruses. CONCLUSION: The established technique provides a simple and powerful tool that expands the diagnostic possibilities, especially for otherwise unidentified or retrospective cases. It further allows insight into the molecular epidemiology of HFRS-causing agents.

Amino Acid Sequence↗
PubMed1976

Formaldehyde-induced hemolysis during chronic hemodialysis.

We investigated an outbreak of hemolytic anemia among patients on hemodialysis shortly after the installation of a new water-filtration system. Using in vitro technics, we demonstrated that a water-soluble inhibitor of red-cell metabolism could easily be extracted from the intact filters. Subsequent experiments showed this toxic substance to be formaldehyde, a potent reducing agent whose mechanism of action involves conversion of NAD to NADH. This alteration of the redox state of the erythrocyte leads to inhibition of glycolysis at the level of glyceraldehyde 3-phosphate dehydrogenase and rapid decline in cellular energy (ATP) stores. Because formaldehyde is widely used as a preservative for dialysis equipment, the toxicity of this agent for red blood cells is of clinical importance.

Adenosine Triphosphate↗
PubMed2006

The roaming atom pathway in formaldehyde decomposition.

We present a detailed experimental and theoretical investigation of formaldehyde photodissociation to H(2) and CO following excitation to the 2(1)4(1) and 2(1)4(3) transitions in S(1). The CO velocity distributions were obtained using dc slice imaging of single CO rotational states (v=0, j(CO)=5-45). These high-resolution measurements reveal the correlated internal state distribution in the H(2) cofragments. The results show that rotationally hot CO (j(CO) approximately 45) is produced in conjunction with vibrationally "cold" H(2) fragments (v=0-5): these products are formed through the well-known skewed transition state and described in detail in the accompanying paper. After excitation of formaldehyde above the threshold for the radical channel (H(2)CO-->H+HCO) we also find formation of rotationally cold CO (j(CO)=5-28) correlated to highly vibrationally excited H(2) (v=6-8). These products are formed through a novel mechanism that involves near dissociation followed by intramolecular H abstraction [D. Townsend et al., Science 306, 1158 (2004)], and that avoids the region of the transition state entirely. The dynamics of this "roaming" mechanism are the focus of this paper. The correlations between the vibrational states of H(2) and rotational states of CO formed following excitation on the 2(1)4(3) transition allow us to determine the relative contribution to molecular products from the roaming atom channel versus the conventional molecular channel.

Carbon Monoxide↗
PubMed1977

Sensory irritation to formaldehyde and acrolein during single and repeated exposures in mice.

Mice were exposed to various concentrations of formaldehyde or acrolein. Concentration-response relationships were developed by measuring per cent decrease in respiratory rate, indicating upper respiratory tract sensory irritation. Relationships are presented between the concentration associated with a 50% respiratory decrease and TLVs. A summary of other animal inhalation studies is presented. The basis for the acrolein and formaldehyde TLVs are reviewed. Mice exposed for 4 days showed increasing sensitivity daily for both compounds. A re-evaluation of the TLVs is suggested.

Acrolein↗