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PubMed2004

Quantitative determination of formaldehyde in cosmetics using a combined solid-phase microextraction-isotope dilution mass spectrometry method.

Solid-phase microextraction (SPME) in conjunction with isotope dilution mass spectrometry (ID-MS) was employed for the analysis of formaldehyde in cosmetic products. The formaldehyde is derivatized in situ with pentafluorophenyl hydrazine. The formed hydrazone is adsorbed over a poly(dimethylsiloxane)-divinylbenzene-coated fiber and analyzed using gas chromatography-mass spectrometry. The adsorption-time profiles and salting effect were studied. The quantitation was performed by using a stable isotope labeled analogue as an internal standard. The precision, recovery and detection limits were determined with spiked samples. The relative standard deviations from different spiked cosmetic samples were all less than 10% and the recoveries were between 89.00 and 101.23%. The limit of detection was of 0.39 microg/l. Compared with other techniques, the study shown here provides a simple, fast and reliable method for the analysis of formaldehyde in cosmetic products.

Calibration↗
PubMed2006

Chromatographic zinc isotope separation by phenol formaldehyde benzo crown resin.

New types of phenol formaldehyde resin having benzo crown as a functional group were synthesized and applied to zinc isotope chromatographic operation. Zinc adsorption and isotope separation capacities were dramatically improved by using phenol formaldehyde benzo-15-crown-5 resin. Zinc batch adsorption tests were performed by various dehydrated organic solvents. Separation coefficient, epsilon 8.1 x 10(-4) and height equivalent to a theoretical plate (HETP) 0.105 cm for the isotopic pair of 68Zn/64Zn in phenol formaldehyde benzo-15-crown-5 resin were obtained in the case of acetone as the solvent at 298+/-1K.

Adsorption↗
PubMed2026

Covalent surface coordination enables efficient and stable formaldehyde-water co-electrolysis over non-stoichiometric cuprous oxide.

The activity-stability trade-off of copper-based oxide catalysts in formaldehyde oxidation remains a fundamental challenge. Here, we resolve this trade-off by grafting N-heterocyclic carbenes (NHCs) onto non-stoichiometric Cu2+1O nanocubes (denoted as Cu2+1O, a Cu+-rich single-phase oxide) through covalent CuC bonds. This molecular surface coordination strategy delivers two concurrent benefits. First, strong σ-electron donation from NHCs shifts the Cu d-band center from -2.106 eV to -2.416 eV, weakening intermediate adsorption and lowering the reaction free-energy change of the rate-determining step (CHOOH⁎ desorption) from 2.56 eV to 1.38 eV. Second, the covalent CuC anchors suppress copper leaching in alkaline electrolyte by a factor of 160 (from 8 mg L-1 to 0.05 mg L-1 over 100 h). The resulting Cu2+1O-NHC catalyst drives formaldehyde oxidation at an onset potential of 0.1 V vs. RHE (Tafel slope: 590 ± 2 mV dec-1, versus 96 ± 3 mV dec-1 for unmodified Cu2+1O; mean ± SD, n = 3), achieving near-unity Faradaic efficiency for both formate (98.65 ± 0.32%) and anodic H2 evolution from CH bond cleavage (99.14 ± 0.28%). Isotope-labeled DEMS confirms that anodic H₂ originates predominantly from the CH bond of formaldehyde, as no HD or D2 was detected when the reaction was performed in D2O. After 100 h of continuous operation, the cubic morphology remains largely intact. This work establishes covalent surface coordination as a promising molecular strategy to decouple activity and stability in oxide electrocatalysts, potentially extendable beyond the specific case of Cu2+1O for aldehyde oxidation.

Copper oxide catalyst↗
PubMed2006

Hexavalent chromium removal from wastewater using aniline formaldehyde condensate coated silica gel.

A resinous polymer, aniline formaldehyde condensate (AFC) coated on silica gel was used as an adsorbent in batch system for removal of hexavalent chromium from aqueous solution by considering the effects of various parameters like reaction pH, dose of AFC coated silica gel, initial Cr(VI) concentration and aniline to formaldehyde ratio in AFC synthesis. The optimum pH for total chromium [Cr(VI) and Cr(III)] adsorption was observed as 3. Total chromium adsorption was second order and equilibrium was achieved within 90-120 min. Aniline to formaldehyde ratio of 1.6:1 during AFC synthesis was ideal for chromium removal. Total chromium adsorption followed Freundlich's isotherm with adsorption capacity of 65 mg/g at initial Cr(VI) 200mg/L. Total chromium removal was explained as combinations of electrostatic attraction of acid chromate ion by protonated AFC, reduction of Cr(VI) to Cr(III) and bond formation of Cr(III) with nitrogen atom of AFC. Almost 40-84% of adsorbed chromium was recovered during desorption by NaOH, EDTA and mineral acids. AFC coated silica gel can be effectively used for treatment of chromium containing wastewaters as an alternative.

Adsorption↗
PubMed2005

Cytogenetic analysis of nasal mucosa cells and lymphocytes from high-level long-term formaldehyde exposed workers and low-level short-term exposed waiters.

The evidence for genotoxic potential of formaldehyde (FA) in humans is insufficient and conflicting. We previously reported a higher frequency of micronuclei in nasal and oral exfoliative cells from students exposed to formaldehyde vapor for short-term. To further evaluate the genetic effects of long-term occupational exposure to FA and short-term exposure to FA of indoor sources, the frequencies of micronuclei (MN) in nasal mucosa cells, sister chromatid exchanges (SCEs) of peripheral lymphocytes, and the lymphocyte subsets were evaluated in 18 non-smoking workers (mean exposure duration was 8.6 years) in an FA factory and 16 non-smoking waiters exposed to FA for 12 weeks in a ballroom. A non-smoking student group without occupational exposure (n=23) to FA was used as control. The 8h time-weighted average (TWA) concentrations of formaldehyde was 0.985+/-0.286 mg/m3 with the ceiling exposure concentration of 1.694 mg/m3 in the workshop, and 0.107+/-0.067 mg/m3 in the ballroom (5 h TWA). Higher frequencies of micronuclei per thousand cells in nasal mucosa cells of workers versus control (2.70+/-1.50 versus 1.25+/-0.65, p<0.05) and higher frequency of SCEs in peripheral lymphocytes of workers group (8.24+/-0.89 versus 6.38+/-0.41, p<0.05) were observed. Increased frequency of micronuclei in nasal mucosa cells or SCE in peripheral lymphocytes was not found among waiters group. The results suggest that the genotoxic potential of high level FA exposure may have occupational risks in long-term exposure groups.

Adolescent↗
PubMed2006

Genotoxic risk assessment of pathology and anatomy laboratory workers exposed to formaldehyde by use of personal air sampling and analysis of DNA damage in peripheral lymphocytes.

A study was conducted to evaluate the genotoxic effect of occupational exposure to formaldehyde on pathology and anatomy laboratory workers. The level of exposure to formaldehyde was determined by use of passive air-monitoring badges clipped near the breathing zone of 59 workers for a total sampling time of 15 min or 8 h. To estimate DNA damage, a chemiluminescence microplate assay was performed on 57 workers before and after a 1-day exposure. Assessment of chromosomal damage was carried out by use of the cytokinesis-blocked micronucleus assay (CBMN) in peripheral lymphocytes of 59 exposed subjects in comparison with 37 controls matched for gender, age, and smoking habits. The CBMN assay was combined with fluorescent in situ hybridization with a pan-centromeric DNA probe in 18 exposed subjects and 18 control subjects randomized from the initial populations. Mean concentrations of formaldehyde were 2.0 (range <0.1-20.4 ppm) and 0.1 ppm (range <0.1-0.7 ppm) for the sampling times of 15 min and 8 h, respectively. No increase in DNA damage was detected in lymphocytes after a one-workday exposure. However, the frequency of binucleated micronucleated cells was significantly higher in pathologists/anatomists than in controls (16.9‰±9.3 versus 11.1‰±6.0, P=0.001). The frequency of centromeric micronuclei was higher in exposed subjects than in controls (17.3‰±11.5 versus 10.3‰±7.1) but the difference was not significant. The frequency of monocentromeric micronuclei was significantly higher in exposed subjects than in controls (11.0‰±6.2 versus 3.1‰±2.4, P<0.001), while that of the acentromeric micronuclei was similar in exposed subjects and controls (3.7‰±4.2 and 4.1‰±2.7, respectively). The enhanced chromosomal damage (particularly chromosome loss) in peripheral lymphocytes of pathologists/anatomists emphasizes the need to develop safety programs.

Adult↗
PubMed2005

Wet and dry deposition of formaldehyde in Izmir, Turkey.

Samples were collected between May 2003 and May 2004 in Izmir, Turkey to measure dry and wet deposition of formaldehyde (HCHO). Particle-phase HCHO fluxes measured with dry deposition plates ranged between 2 and 56 microg m(-2) day(-1) (average+/-SD, 17+/-12 microg m(-2) day(-1)). Particulate phase dry deposition velocities calculated using the particulate fluxes measured and ambient particulate concentrations ranged from 0.1 to 9.6 cm s(-1) (1.4+/-1.4 cm s(-1)). The particulate overall dry deposition velocity agreed well with those measured previously for other pollutants using the same method. Formaldehyde concentration measured in 27 rain samples collected at the sampling site ranged between 10 and 304 microg l(-1). The annual formaldehyde wet deposition was calculated as 31.4 mg m(-2) year(-1). The annual HCHO total deposition (wet+dry) was dominated by wet deposition (83.7%).

Air Pollutants↗
PubMed2005

Different cytoprotective effect of antioxidants and change in the iron regulatory system in rodent cells exposed to paraquat or formaldehyde.

To study the mechanism of toxicity of paraquat and formaldehyde, the response of oxidant-exposed cultured NIH3T3 cells to antioxidants or an iron chelator was investigated. Paraquat-induced cell death was reduced by treatment with 10 microM pyrrolidine dithiocarbamate (PDTC) and 10 microM desferrioxamine (DFO), but not with N-acetyl-L-cysteine (NAC). Cells were protected from formaldehyde-induced cytotoxicity by 1 mM NAC, but not by PDTC or DFO. Moreover, paraquat modulated the cellular iron regulatory system. Paraquat induced a time-dependent increase in the binding of iron regulatory protein 1 (IRP1) to iron-responsive element (IRE), and the enhanced IRP1 activity continued over 24 h. On the other hand, no induction of increased IRP1 binding to IRE was observed in rodent cells exposed to formaldehyde. Previously, we observed stimulation of EpRE-mediated ferritin mRNA expression in the cells exposed to hydrogen peroxide. However, paraquat did not induce any transcriptional activation of ferritin genes. These results suggest that intracellular iron may be involved in paraquat-mediated cytotoxicity and the influence of paraquat on iron metabolism differs from that of hydrogen peroxide.

Animals↗
PubMed1997

Lack of evidence for the involvement of formaldehyde in the hepatocarcinogenicity of methyl tertiary-butyl ether in CD-1 mice.

The oxygenated fuel additive methyl tertiary-butyl ether (MTBE) induced hepatocellular adenomas in female but not male CD-1 mice exposed to 8000 ppm; liver cancer was not induced in female or male mice exposed to 3000 or 400 ppm. Since MTBE is metabolized by cytochrome P450 to formaldehyde (HCHO), a potentially mutagenic intermediate capable of forming DNA-protein cross-links (DPX), the formation of DPX and of another HCHO derivative, RNA-formaldehyde adducts (RFA), from MTBE was investigated using freshly isolated hepatocytes from female CD-1 mice incubated with MTBE-(O-methyl-14C). DPX and RFA were detected, but the adduct yields were very small and were independent of the concentration of MTBE in the hepatocyte suspension over a wide concentration range (0.33-6.75 mM). Similar results were obtained using hepatocytes from male B6C3F1 mice and male F344 rats. Induction of cytochrome P450 by pretreatment of mice with MTBE prior to isolation of hepatocytes did not result in a measurable increase in the yields of either DPX or RFA. In contrast to the absence of concentration-dependent DPX and RFA formation from MTBE, there was a marked, concentration-dependent increase in the yields of both DPX and RFA when [14C]formaldehyde was added directly to the medium. These results suggest that the metabolism of MTBE to HCHO approaches saturation at concentrations below 0.33 mM, and that the rate of HCHO production from metabolism of MTBE is slow relative to the rate of HCHO metabolism. The lack of concentration dependence and the absence of species or sex differences in the formation of DPX and RFA from MTBE indicate that metabolism of MTBE to HCHO is not a critical component of its carcinogenic mechanism in mice.

Air Pollutants↗
PubMed1988

Comparison of health of occupants and characteristics of houses among control homes and homes insulated with urea formaldehyde foam. I. Methodology.

The methodology of a study in which a comparison is made of the health and house characteristics of the occupants of 231 control homes and 571 houses containing urea formaldehyde foam insulation (UFFI) is described. All homes and occupants were examined on two occasions separated by an interval of 12 months, during which two-thirds of the UFFI houses performed remedial work. The occupants were examined using a health questionnaire and a series of objective tests including pulmonary function, nasal airway resistance, sense of smell, nasal surface cytology, and patch tests. The houses were assessed using a questionnaire and measurements of indoor formaldehyde and carbon dioxide levels. No obvious bias has been identified in this survey with respect to the representativeness of the population studied, the classification of the UFFI and control groups, and the input from both the respondents and observers. The symptom responses made by individuals within the same households were not correlated. Quality control assessment of the objective health tests and formaldehyde sampling and assays demonstrated that these procedures remained stable over the two phases of the study, with the exception of the expected decrease in the pulmonary flow rates over 1 year and a small unexpected increase in the forced vital capacity and the forced expiratory volume in 1 s.

Airway Resistance↗
PubMed2000

Poly(allylamine) beads as selective sorbent for preconcentration of formaldehyde and acetaldehyde in high-performance liquid chromatographic analysis.

Formaldehyde and acetaldehyde in water were determined by preconcentration with poly(allylamine) beads, derivatization with 2,4-dinitrophenylhydrazine (DPH) and analysis by HPLC. Poly(allylamine) beads (0.5 g) were used to adsorb formaldehyde and acetaldehyde at 1.2-150 microg l(-1) and 3.5-220 microg l(-1) from water (1 l). The concentration factor is 50 fold. The aldehydes were eluted and derivatized with 2 mM DPH in 0.5 M H2SO4 (10 ml). The time of analysis was 1 h. The detection limits (S/N=3) for formaldehyde and acetaldehyde were 0.6 and 2 microg l(-1), respectively.

Acetaldehyde↗
PubMed2001

Improved measurement of formaldehyde in water-soluble polymers by high-performance liquid chromatography coupled with post-column reaction detection.

An improved methodology for the analysis of free formaldehyde in water-soluble polymers used for industrial water treatment is reported. Previously, derivatization prior to HPLC or colorimetric techniques has been used. The data generated by these approaches are suspect in that the derivatizing agent can react with the polymer or other sample components to produce high results. Post-column reaction derivatization is applied after separation of the free formaldehyde from the product interferences. The type of polymer product analyzed influences the choice of column(s). The degree of high bias of the commonly used 2,4-dinitrophenylhydrazine pre-column derivatization is reported and the results are compared to those with the post-column reaction for two polymer products. This method, being more selective, should be applicable to any polymer containing formaldehyde.

Chromatography, High Pressure Liquid↗
PubMed1989

High-performance liquid chromatographic determination of free formaldehyde in cosmetics.

An improved, sensitive method for the determination of formaldehyde in cosmetics and other commercial products is reported. The procedure is based on dilution of the sample with tetrahydrofuran-water (9:1), followed by precolumn derivatization with 2,4-dinitrophenylhydrazine and direct reversed-phase high-performance liquid chromatography. The formaldehyde derivative is stabilized in the reaction medium by addition of phosphate buffer and neutralization and detected in less than 10 min by the standard additions methods. The method also appears to be suitable for the direct evaluation of the formaldehyde donors used in cosmetics as preservatives.

Chromatography, High Pressure Liquid↗
PubMed1999

Comments on the purported generation of formaldehyde and adduct formation from the sweetener aspartame.

A recent paper by Trocho et al. (1) describes experiments meant to show that formaldehyde adducts are formed when rats are administered the sweetener aspartame. These authors assume that the methanol carbon of aspartame generates formaldehyde which then forms adducts with protein, DNA, and RNA. Doses employed range widely. In this letter, studies which have been published previously and which were not cited by these authors are reviewed in order to put into perspective the disposition of methanol and formaldehyde in monkeys and humans, species relevant to the toxicity of methanol and its toxic metabolite, formic acid.

Animals↗
PubMed1997

Shrinkage and distortion of the rabbit corneal endothelial cell mosaic caused by a high osmolality glutaraldehyde-formaldehyde fixative compared to glutaraldehyde.

The purpose of this study was to quantitatively compare cell dimensions and cell layer organization of the corneal endothelium after chemical fixation. Rabbit corneas (9-10 weeks of age) were prepared immediately postmortem for transmission electron microscopy (TEM) and scanning electron microscopy (SEM) using either a widely used high osmolality fixative (glutaraldehyde-formaldehyde, after Karnovsky; 1% formaldehyde, 2.5% glutaraldehyde, 0.1 M cacodylate, pH 7.6, 850 mOsm/kg) or a glutaraldehyde fixative (2% glutaraldehyde in 80 mM cacodylate, pH 7.4, 330 mOsm/kg). With the glutaraldehyde-formaldehyde fixative, TEM revealed gross shrinkage (up to 40%) and distortion of the cytoplasm and organelles, while the regions of the cell-cell junctions were not attenuated but included dilated extracellular space. With the glutaraldehyde fixative, TEM also revealed shrinkage but the cytoplasm was less compact than with the high osmolality fixative. The overall cell shrinkage and relative accentuation of the cell-cell borders was confirmed by SEM, which also revealed that the 11 to 20% area shrinkage was also related to the number of cell sides.

Animals↗
PubMed1991

Studies of inspiratory airflow patterns in the nasal passages of the F344 rat and rhesus monkey using nasal molds: relevance to formaldehyde toxicity.

For highly water soluble and reactive gases, such as formaldehyde, the reported distribution of nasal lesions in rats and rhesus monkeys following inhalation exposure may be attributable, at least in part, to regional gas uptake patterns that are a consequence of nasal airflow characteristics. Inspiratory nasal airflow was studied at flow rates across the physiologic range using a unidirectional dynamically similar water-dye siphon system in clear acrylic molds of the nasal airways of F344 rats and rhesus monkeys. In both species there were complex and inspiratory flow streams, exhibiting regions of simple laminar, complex secondary (vortices, eddies, swirling), and turbulent flows, with only minor effects of the volumetric flow rates studied on these flow patterns. There was a precise association between points of dye intake at the nostril with complex but generally coherent streaklines throughout the nose, indicating the potential for sensitive dependence of nasal airflow on nostril geometry. On the basis of these studies, a classification for the major airways (meatuses) in the nasal passages of rats and rhesus monkeys was proposed. The spiral shape of the anterior nasal airway of the rat was considered to play an important role in local mixing of inspired airstreams. In the rhesus monkey, the complex geometry of the nasal vestibule contributed to the formation of secondary flows and turbulence in the anterior nose, which represents a potentially important difference between rheusus monkeys and humans. There was a good correlation between routes of flow, regional secondary flows, turbulence, and impaction of airstreams on the airway wall, with the reported distribution of formaldehyde-induced nasal lesions in rats and rhesus monkeys. These studies support the proposal that nasal airflow patterns play an important role in the distribution of lesions induced by formaldehyde.

Administration, Inhalation↗
PubMed2002

Pertubated loading of a formaldehyde waste in an anaerobic granular activated carbon fluidized bed reactor.

The objective of this study was to examine the biological treatment of a formaldehyde waste simulating wastewater from a resin production facility. An analysis of degradation of a high strength organic waste stream containing formaldehyde in an anaerobic fluidized bed granular activated carbon bioreactor (AFBGAC) is presented. In the first part of this study, the AFBGAC bioreactor was operated for a total of 700 days under four different continuous loading rates, to optimize the hydraulic retention time, until steady state performance was obtained. In the second part, the effect of substrate perturbation on effluent quality was examined by periodically loading the reactor using five distinct perturbation schemes to simulate different production shifts. The feed under the first three perturbation schemes was applied in cycles of 16 h on and 8 h off, 12 h on and 12 h off, and 8 h on and 16 h off. The fourth scheme applied feed at 8 h on and 16 h off with no feed on weekends. The fifth scheme examined the long-term effect of substrate limitation using the 8 h on and 16 h off loading cycle with a feed interruption of 9 days. The organic loading per day was kept constant throughout the feed perturbation study. The reactor removed more than 95% of the dissolved organic carbon content of the waste under both continuous and cyclic loading. Formaldehyde removal rates of up to 99.99% were achieved under continuous loading while removal rates ranged from 97.4% to 99.9% under cyclic loading. Although the AFBGAC failed occasionally due to excessive buildup of attached biomass during the phase of continuous loading, it still maintained excellent overall removal efficiencies. It also showed resilience to substrate limitations and load perturbations under dynamic loadings. The results presented in this study provide a promising strategy to treat inhibitory wastes.

Bacteria, Anaerobic↗
PubMed1994

When NADPH diaphorase (NADPHd) works in the presence of formaldehyde, the enzyme appears to visualize selectively cells with constitutive nitric oxide synthase (NOS).

The NADPH diaphorase (NADPHd) reaction for nitric oxide synthase (NOS) visualization suffers from the circumstance that the diaphorase activity of NOS represents only part of the total diaphorase activity, and so far all efforts to make the reaction more specific for routine studies failed. The present investigation describes a simple procedure for mouse tissue, which allows the selective staining primarily of neurons, vascular endothelial cells and macula densa cells, those cells where constitutive NOS has been described reliably. In this method unfixed cryosections and 0.5-1% phosphate-buffered formaldehyde containing 0.5 mg NADPH/1 ml and 1 mg nitro BT/1 ml are used. Compared to strong prefixation with formaldehyde after which many additional cells are still positive for NADPHd, presence of formaldehyde in the incubation medium obviously allows the selective reaction of NOS-positive cells. In conclusion, compared with the original technique a more specific method for the visualization of the NADPHd activity of NOS appears to be available now and can be used for NOS studies in all kinds of mammalian species.

Amino Acid Oxidoreductases↗