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PubMed1983

The determination of formaldehyde in beer and soft drinks by HPLC of the 2,4-dinitrophenylhydrazone derivative.

A simple procedure was developed for the determination of formaldehyde in samples of beer and soft drinks. A volume of sample was distilled and the aqueous distillate containing the formaldehyde collected directly in a solution of 2,4-dinitrophenylhydrazine. The resulting hydrazone was extracted and analysed by reversed-phase high-performance liquid chromatography with UV absorbance detection. Levels of formaldehyde found were in the low mg/kg range. Detection limits were less than 0.1 mg/kg of sample. Results were confirmed by mass spectrometry (probe) of the derivatives after fraction collection from the HPLC.

Beer↗

PubMed2003

Video exposure assessments demonstrate excessive laboratory formaldehyde exposures.

Video exposure assessments were conducted in a comparative anatomy laboratory using formaldehyde-preserved sharks and cats. Work in the facility using time-integrated samplers indicated personal and area concentrations generally below the current OSHA permissible exposure limit. However, complaints about room air quality were frequent and routine. Using a photoionization detector with an integral data logger, total ionizables present were sampled as a surrogate for formaldehyde. After synchronizing time tracks from the datalogger concentrations with simultaneously created videotapes of laboratory tasks, composite video exposure overlays were generated. Use of this video exposure method revealed very short-lived, excessively high peak exposure events, whereas conventional time-weighted averages indicated the majority (30/32) of personal exposures were below the OSHA limit of 0.75 ppm. These legally acceptable exposure levels were associated with self-reported symptoms of burning nose and eyes and eye irritation. Thus, transient peak formaldehyde concentrations not detected by longer term averaging studies could be responsible for the health effects reported. The video exposure monitoring method demonstrated that close dissection work, opening peritoneal cavities, and specimen selection activities were most likely the causes of elevated student exposures. Teaching assistants' exposures were the highest, exceeding OSHA limits on several occasions. The utility of the video monitoring method for conducting enhanced, critical task exposure assessments is discussed.

Air Pollutants, Occupational↗

PubMed2001

Occupational exposure to harmful chemical substances while processing phenol-formaldehyde resins.

Air pollutants emitted while processing phenol-formaldehyde resins have been investigated. Gas chromatography-mass-selective detection was used to separate and identify chemical compounds. It was determined that workers were exposed to formaldehyde in all workplaces. Besides, phenol, acetaldehyde, acrylaldehyde, 2-furaldehyde, xylene, ethylbenzene, toluene, tetrachlorethene, ethyl acetate, butyl acetate were found during the production of frictional materials; and 2-furaldehyde, phenol, naphthalene, 2-furanmethanol, polycyclic aromatic hydrocarbons (PAHs) during the production of abrasive materials. Quantitative analyses were performed with gas chromatography and high performance liquid chromatography. Assessment of occupational exposure indicated that chemical compounds emitted during the investigated processes might be dangerous for human health, mainly because of suspected carcinogenic compounds: formaldehyde and PAHs.

Air Pollutants, Occupational↗

PubMed2006

Bioconversion of methanol to formaldehyde. II. By purified methanol oxidase from modified yeast, Hansenula polymorpha.

Modified methylotrophic yeast Hansenula polymorpha (HP A16) that was obtained by repressing leucine oxotrophic yeast; a wild type of Hansenula polymorpha CB4732 was used in this study. The yeast is grown with methanol, which is used as a sole carbon source, using various methanol concentrations and temperatures, and methanol oxidase (MOX) which is a key enzyme of methanol metabolism; production is maximized. Whole yeast cells were cultivated under optimized inoculation conditions; they were separated into two portions. One portion of these cells was directly used in bioconversion of methanol to formaldehyde. The second portion of the free cells was broken into pieces and a crude enzyme extract was obtained. The MOX enzyme in this extract was purified via salt precipitation, dialysis, and chromatographic methods. The purified MOX enzyme of yeast (HP A16) oxidized the methanol to formaldehyde. Optimization of bioconversion conditions was studied to reach maximum activity of enzyme. The optimum temperature and pH were found to be 35 degrees C and pH 8.0 in boric acid/NaOH buffer, and it was stable over the pH range of 6-9, at the 20 degrees C 15 min. A suitable reaction period was found as 50 min. The enzyme indicated low carbon primary alcohols (C2 to C4), as well as methanol. Initially, MOX activity increased with the increase of methanol concentration, but enzyme activity decreased. The apparent Km and Vmax values for methanol substrate of HP A16 MOX were 0.25 mM and 30 U/mg, respectively. The purified MOX enzyme was applied onto sodium dodecyl sulphate-polyacrylamide gel electrophoresis; molecular weight of the enzyme was calculated to be about 670 kDa. Each MOX enzyme is composed of eight identical subunits, each of whose molecular weight is around 82 kDa and which contain eight moles of FAD as the prosthetic group, and the pI of the natural enzyme is found to be 6.4. The purified MOX enzyme was used in the bioconversion of methanol to formaldehyde as a catalyst; this conversion was compared to the conversion percentages of whole cells in our previous article in terms of catalytic performances.

Alcohol Oxidoreductases↗

PubMed1984

Formaldehyde and hepatotoxicity: a review.

Exposure to formaldehyde appears to be associated with hepatoxicity in many species, including humans, following injection, ingestion, or inhalation. Macroscopic, microscopic, and biochemical manifestations in the liver include alterations in weight, centrilobular vacuolization, focal cellular necrosis, and increased alkaline phosphatase concentrations. Time-related changes in the pattern of the effects are suggested as one goes from acute exposure by inhalation at greater concentrations to repeated exposure at lesser concentrations. Although the hepatic changes are generally not extensive and can be reversible following acute exposure, the potential exists for them to progressively become more serious with repeated exposures. There are several possible mechanisms for the toxicity. Depending on the route of exposure could include direct effects on hepatocytes and/or indirect effects through the circulatory and immune systems. The catabolism of formaldehyde includes conversion to CO2 by reactions involving glutathione. Many hepatotoxic chemicals require glutathione for detoxification. Formaldehyde may then have the potential to cause additive toxicity with such chemicals in some circumstances.

Alkaline Phosphatase↗

PubMed1980

Solid sorbent tube sampling and ion chromatographic analysis of formaldehyde.

A new method for the collection and analysis of atmospheric formaldehyde is described. Known concentrations of formaldehyde were generated and collected on solid sorbent tubes containing impregnated charcoal which converted formaldehyde to formate. After desorption with dilute hydrogen peroxide, the formate was analyzed by ion chromatography. The sample generation system, collection on impregnated charcoal, desorption, ion chromatographic analysis, and recoveries are presented. The overall recovery of laboratory generated samples was 100% with 11% relative standard deviation. These samples were collected at 50 cc/min and 200 cc/min.

Air↗

PubMed1982

Workplace air sampling and polarographic determination of formaldehyde.

A polarographic method has been developed for the determination of formaldehyde in workplace air. Samples are collected in midget fritted glass bubblers containing an aqueous solution of 10% methanol. The collected formaldehyde in the absorbent solution is derivatized with hydrazine reagent to form a formaldehyde hydrazone compound. An aliquot of the resulting solution is analyzed by differential pulse polarography at a dropping mercury electrode. The sample generation system, impinger collection, polarographic analysis, and precision and accuracy data are described. The method was validated over the range of 5.8 to 17.7 mg/cu m, which corresponds to 0.5 to 2 times the (peak) OSHA-PEL for a 30-liter sample at a flow rate of 1 Lpm. The average recovery was 103%. The pooled coefficient of variation or relative standard deviation was 0.08.

Air Pollutants↗

PubMed1983

Formaldehyde in office and commercial environments.

The objective of these investigations was to determine a potential cause for occupational discomfort and illness in various nonindustrial situations. Since exposure to commonly used industrial chemicals was nonexistent from a job related situation, the physical environment was the only clue to potential agents. The offices had urea-formaldehyde resin products present as a common factor. Airborne measurements showed presence of formaldehyde in extremely low concentrations and well within the OSHA Standards. Current studies are examining the formaldehyde levels for various nonindustrial exposures reported.

Air Pollutants↗

PubMed1983

Eye irritation response of humans to formaldehyde.

Human panelists sensitive to formaldehyde eye irritation were exposed to low concentrations of formaldehyde vapor (0.35 to 1.0 ppm) for 6 minutes. Eye irritation was evaluated by time to detection of the first trace of irritation and by subjective ranking of severity. Both time to response and severity appeared to be functions of formaldehyde concentration. Severity of response was above "slight" only with highest test concentration, 1.0 ppm.

Dose-Response Relationship, Drug↗

PubMed1984

Formaldehyde concentrations in workrooms resulting from off-gassing from sandpaper.

Formaldehyde was found to off-gas from flint sandpaper that contained an urea-formaldehyde resin as the minor component in a double glue system. Approximately 2000 sheets of sandpaper in a 115 m3 (4050 ft3) ship's storeroom with no mechanical ventilation produced a formaldehyde concentration of at least 4.5 ppm that was uniform throughout the compartment. A contributing factor was elevated compartment temperature due to high ambient temperature and the heating of the ship's steel hull by direct exposure to the sun.

Air Pollutants, Occupational↗

PubMed1985

Formaldehyde (CH2O) concentrations in the blood of humans and Fischer-344 rats exposed to CH2O under controlled conditions.

The effect of exposure to formaldehyde (CH2O) on the CH2O concentration of the blood was determined. Eight male F-344 rats were exposed to 14.4 +/- 2.4 ppm of CH2O for 2 hours and the blood was collected immediately after exposure. Formaldehyde concentrations in the blood were determined by gas chromatography/mass spectrometry. The blood of eight rats unexposed to CH2O was collected and analyzed in the same manner. Measured CH2O concentrations (micrograms/g of blood) were: controls, 2.24 +/- 0.07; exposed, 2.25 +/- 0.07 (mean +/- S.E.). Formaldehyde concentrations in human blood were determined by analyzing samples of venous blood collected before and after exposure of six human volunteers (4 M, 2 F) to 1.9 +/- 0.1 ppm of CH2O for 40 min. Average CH2O concentrations (micrograms/g of blood) were: before exposure, 2.61 +/- 0.14; after exposure, 2.77 +/- 0.28. In neither experiment was there a statistically significant effect of exposure on the average CH2O concentration of the blood. However, human subjects differed significantly with respect to their blood CH2O concentrations, and significant differences (either an increase or a decrease) were found between the CH2O concentrations of the blood taken before and after exposure from some of the subjects, suggesting that blood CH2O concentrations may vary with time.

Adult↗

PubMed1985

A survey of typical exposures to formaldehyde in Houston area residences.

A survey of indoor air quality under warm weather conditions, in a variety of Houston area residences not selected in response to occupant complaints, revealed a distribution of indoor formaldehyde concentrations ranging from less than 0.008 ppm to 0.29 ppm, with an arithmetic mean of 0.07 ppm. Approximately 15% of the monitored residences had concentrations greater than 0.10 ppm. Formaldehyde levels were observed to depend on both age of dwelling and the structural classification of the residence. These factors are not independent and reflect the influence of more fundamental variables, such as the rate of exchange of indoor and outdoor air and the overall emission potential of indoor materials. The results of this survey suggest that considerable population exposures to excess (greater than 0.10 ppm) formaldehyde concentrations may occur in the residential environment, indicating the need for improved control strategies.

Air Pollutants↗

PubMed1985

Formaldehyde: a comparative evaluation of four monitoring methods.

The performances of four formaldehyde monitoring devices were compared in a series of laboratory and field experiments. The devices evaluated included the DuPont C-60 formaldehyde badge, the SKC impregnated charcoal tube, an impinger/polarographic method and the MDA Lion formaldemeter. The major evaluation parameters included: concentration range, effects of humidity, sample storage, air velocity, accuracy, precision, interferences from methanol, styrene, 1,3-butadiene, sulfur dioxide and dimethylamine. Based on favorable performances in the laboratory and field, each device was useful for monitoring formaldehyde in the industrial work environment; however, these devices were not evaluated for residential exposure assessment. The impinger/polarographic method had a sensitivity of 0.06 ppm, based on a 20-liter air sample volume, and accurately determined the short-term excursion limit (STEL). It was useful for area monitoring but was not very practical for time-weighted average (TWA) personal monitoring measurements. The DuPont badge had a sensitivity of 2.8 ppm-hr and accurately and simply determined TWA exposures. It was not sensitive enough to measure STEL exposures, however, and positive interferences resulted if 1,3-butadiene was present. The SKC impregnated charcoal tube measured both TWA and STEL concentrations and had a sensitivity of 0.06 ppm based on a 25-liter air sample volume. Lightweight and simple to use, the MDA Lion formaldemeter had a sensitivity of 0.2 ppm. It had the advantage of giving an instantaneous reading in the field; however, it must be used with caution because it responded to many interferences. The method of choice depended on the type of sampling required, field conditions encountered during sampling and an understanding of the limitations of each monitoring device.

Air Pollutants, Occupational↗

PubMed1986

Wood dust and formaldehyde exposures in the cabinet-making industry.

Time-weighted average (TWA) personal total and respirable dust exposures were determined gravimetrically for 48 subjects in 4 cabinet-making plants. TWA personal formaldehyde exposures also were obtained, with the use of 3M 3750 passive monitors. Selective area sampling for formaldehyde was undertaken using two methods. The results obtained with the passive monitors were compared to the standard chromotropic acid impinger method. Considerable variation was noted in the dust exposures. Cabinet-makers exposed to softwoods were found to have a mean exposure of approximately one half of the current applicable ACGIH TWA-TLV, while hard-wood exposure was twice the applicable TWA-TLV. The highest dust exposures were recorded for those workers sanding, the mean total dust being 2.91 mg/m3 (S.E. 0.70) and respirable dust 0.63 mg/m3 (S.E. 0.20). Sanding operations also were found to produce a higher proportion of respirable dust (22%) than other woodworking operations (6%-14%). Workers in assembly areas also were found to have higher dust exposures, likely reflecting the fact that conventional dust collection devices for stationary woodworking equipment are not appropriate for hand held tools and hand sanding. The importance of making respirable dust measurements is discussed. The poor correlation between paired total and respirable dust concentrations indicates that both measurements should be made. Some potential limitations to respirable wood dust sampling using 10 mm nylon cyclones are noted, however. Area dust concentrations were found to be significantly lower than personal exposures, emphasizing the importance of personal sampling data. Formaldehyde vapor exposures were very low, with a mean of 0.06 ppm (S.E. 0.01).

Air Pollutants, Occupational↗

PubMed1988

Acute effect upon pulmonary function of low level exposure to phenol-formaldehyde-resin-coated wood.

In order to determine whether phenol-formaldehyde-resin-coated wood particles would cause an acute decline in pulmonary function, 176 workers in 2 oriented strandboard production plants were given respiratory questionnaires and pulmonary function tests before and during their work shifts. Measurements of dust and adsorbed formaldehyde were made on the same day as the pulmonary function tests. Measured formaldehyde levels were low, and measured dust levels were low to moderate. There was no evidence of an acute effect upon pulmonary function.

Air Pollutants, Occupational↗

PubMed1997

Field precision of formaldehyde sampling and analysis using NIOSH method 3500.

This study examined the field precision of National Institute for Occupational Safety and Health (NIOSH) Method 3500, also known as chromotropic acid method, in the range of exposure limit covers the Occupational Safety and Health Administration (OSHA) permissible exposure limit of 0.75 ppm and the OSHA action level of 0.5 ppm airborne formaldehyde. Using this method, 78 area samples (25 sets of replicate samples) were collected in a workplace and analyzed. The concentrations of formaldehyde ranged from 0.05 to 1.72 ppm with a mean +/- standard deviation of 0.95 +/- 0.31 ppm. The precision (coefficient of variation, CV) of 25 sets of replicated samples ranged from 0.03 to 0.24 with an overall (pooled) precision of 0.09, which is in agreement with that stated in NIOSH Method 3500. In 68% of replicate samples the precision was equal to or less than 0.09. The relative accuracy of the sampling and analytical procedure used in this study was evaluated by collecting 12 sets of side-by-side replicate samples using both NIOSH Method 3500 and OSHA Method 5.2 Method 53 was used to determine whether the concentrations of formaldehyde were within the desired range. The overall mean concentrations were 0.98 +/- 0.42 for Method 3500 and 0.78 +/- 0.28 ppm for Method 5.2. These were no statistically different. The pooled CVs were 0.114 and 0.076 for Method 3500 and Method 52, respectively.

Air Pollutants, Occupational↗

PubMed2000

Preparation and in vitro evaluation of chitosan matrices cross-linked by formaldehyde vapors.

Rifampicin-chitosan matrices were prepared by a chemical cross-linking method to develop a sustained-release form. The effects of cross-linking agent (formaldehyde) on the drug release rate and release kinetics were investigated in this study. Moreover, the kinetics of rifampicin released from chitosan matrices exposed to formaldehyde vapors for predetermined time intervals were analyzed using Ritger and Peppas exponential equation. The in vitro release kinetics exhibited a non-Fickian transport model. Increasing the exposure time to formaldehyde vapors decreased the release rate of rifampicin from chitosan matrices as a result of formation of greater structural strength and tighter texture.

Antibiotics, Antitubercular↗

PubMed1954

The effect of formaldehyde on the oxygen equilibrium of hemoglobin.

1. When formaldehyde (0.10 M) is added to solutions of human hemoglobin, the oxygen affinity of the hemoglobin increases considerably (more than tenfold near pH 7). The interaction between hemes of the same hemoglobin molecule decreases, as shown by a drop in the value of n in Hill's equation from 2.9 to 1.5 or less. 2. In the presence of formaldehyde, both n and the oxygen pressure for half-saturation fall gradually as the pH rises in the range from pH 6.2 to 7.2. 3. Some of the effect of formaldehyde on the oxygen equilibrium may be due to combination with sulfhydryl groups of the protein, but nitrogenous groups are probably also involved.

Formaldehyde↗