Formaldehyde sampling

Figure 8.3.2. Pyrogram of a poly[(phenyl glycidyl ether)-co-formaldehyde] sample with M - 345. Pyrolysis done on 0.4 mg material at 600° C in He, with the separation on a Carbowax type column.

A 55-year-old woman and a 34-year-old man ingested, with suicidal intent, an unknown amount of what was reported to have been formalin (Koppel et al. 1990). The female patient was found in a coma and admitted to the hospital with shock (systolic blood pressure 50 mm Hg), respiratory insufficiency, and metabolic acidosis. The male patient, who had a history of alcohol abuse, was also hospitalized with shock (systolic blood pressure 60 mm Hg), respiratory insufficiency, and metabolic acidosis. Both patients underwent hemodialysis and hemofiltration treatment. Analysis of the formaldehyde samples ingested by both patients showed no evidence that these products contained methanol, although it was expected to have been detected. A chemical-toxicological screening indicated that no drugs other than fonnaldehyde had been ingested neither methanol or ethanol were detected in blood samples. Three... 

The relative standard deviations for sets of 15 repetitive measurements were 1.5% and 0.4% at concentrations of 1 and 10 pg/ml, respectively. The results obtained from this system correlated well with those obtained from the chromotropic acid. The simplicity, versatility, good precision, high sampling rate, and relatively low cost of the system make it attractive for the analysis of large numbers of formaldehyde samples. 

Procedure Formaldehyde sample from the sampler was injected into the carrier stream where it was mixed with pararosaniline and then sulfite to form an alkylsulfonic acid chromophore which can be monitored spectrophotometrically at 570 nm For calibration, standard formaldehydes were sequentially introduced after a stable baseline was obtained At least five consecutively reproducible peaks were recorded for each concentration After each study or each day of operation, the FIA system was cleaned to remove any pararosaniline film, alkylsulfonic acid colored product, or particulate matters This reduced the scattered light in the absorption cell and the staining of the tubing walls. The clean-up procedure was initiated by running distilled deionized water through the system for five minutes followed by another five minutes washing with 0 1 N nitric acid and then flushing the unit for 30 minutes with deionized water The chromotropic acid method was used for comparative studies, and the analytical procedure for the chromotropic acid method was based on the procedure recommended by the American Public Health Association (12) ... 

The flow injection system described here can be used for automated analysis of large numbers of formaldehyde samples. The... 

Analytical Procedure. For the enzymatic method I, 0.98 ml of phosphate buffer (pH 8) and 50 pi of formaldehyde dehydrogenase were pipetted Into a cuvette. To this 400 yl of formaldehyde sample, or standard, were added, and mixed by shaking for 5 seconds. The cuvette was placed In the spectrofluorometer (X ... 

For formaldehyde analysis using method II, phosphate buffer was pipetted Into a sample cuvette, of formaldehyde dehydrogenase, 50 pi of dlaphorase, and 100 pi of resazurln were added. Next 400 p 1 of formaldehyde sample, or... 

These test chambers can be incorporated to the enzymatic methods for formaldehyde determination. Formaldehyde emissions of a product, or mix of products, to the ambient air can be collected in distilled water or 1% sodium bisulfite as the absorbing solution. After collection, formaldehyde samples are analyzed as described above. In the mobile home simulator test method (2J, double or triple impingers, which are placed in series, should be used in order to collect all of the formaldehyde vapor. The test conditions should simulate the actual environment. Several factors such as temperature and relative humidity of the system including the specimens and background of formaldehyde in the test chamber, affect the precision and accuracy of the results. It has been shown that a 7 C change in temperature doubles the emission level (L). The temperature of the test chamber should be... 

NIOSH has developed independent methodologies for acrolein and formaldehyde which recommend the use of reagent-coated adsorbent tubes to collect the aldehydes as stable derivatives. The formaldehyde sampling tubes contain Chromosorb 102 adsorbent coated with N-benzy-lethanolamine (BEA) which reacts with formaldehyde vapor to form a stable o) olidine compound. The acrolein sampling tubes contain XAD-2 adsorbent coated with 2-(hydroxymethyl) piperidine (2-HMP) which reacts with acrolein vapor to form a different, stable oxazolidine derivative. Acrolein does not appear to react with BEA to give a suitable reaction product. Therefore, the formaldehyde procedure cannot provide a common method for both aldehydes. However, formaldehyde does react with 2-HMP to form a very suitable reaction product. It is the quantitative reaction of acrolein and formaldehyde with 2-HMP that provides the basis for this evaluation. 

Reproducibility Samples collected from controlled test atmospheres and a draft copy of this procedure were given to a chemist unassociated with this evaluation. The formaldehyde samples were analyzed following 15 days storage. The average recovery was 96.3% and the standard deviation was 1.7%. 

Procedure Pifty cc of a molal solution of pure sodium sulfite (prepared dissolving 252 g of hydrated sodium sulfite or 126 g of the anhydrous salt in sufficient distilled water to make one liter of solution) and three drops of thymolphthalein indicator solution (0.1 per cent in alcohol) are placed in a 500-cc Erlenmeyer flask and carefully neutralised by titration vith normal sulfuric or hydrochloric acid until the blue color of the indicator has disappeared (one or two drops is sufficient). An accurately measured and substantially neutral formaldehyde sample is then added to the sodium sulfite and the resulting mixture titrated with the standard add to complete decoloration. One cc of normal acid is equivalent to 0.03002 g formaldehyde and the per cent formaldehyde in the sample is determined "by the following equation ... 

To the remainder of the gelatin solution, add 0 5 to o 8 g. of finely powdered commercial trypsin and incubate at 40 . Carry out the formaldehyde titration on 25 ml. samples at intervals as above. 

After adding p-rosaniline and formaldehyde, the colored solution was diluted to 25 ml in a volumetric flask. The absorbance was measured at 569 nm in a 1-cm cell, yielding a value of 0.485. A standard sample was prepared by substituting a 1.00-mL sample of a standard solution containing the equivalent of 15.00 ppm SO2 for the air sample. The absorbance of the standard was found to be 0.181. Report the concentration of SO2 in the air in parts per million. The density of air maybe taken as 1.18 g/L. 

Formaldehyde from cigarette smoke is collected by trapping the smoke in a 1-L separatory funnel and extracting into an aqueous solution. To aid in its detection, cysteamine is included in the aqueous extracting solution, leading to the formation of a thiazolidine derivative. Samples are analyzed... 

LLDPE can present a certain health hazard when it bums, since smoke, fumes, and toxic decomposition products are sometimes formed in the process. Exposure to burning LLDPE can cause irritation of the skin, eyes, and mucous membranes of the nose and throat due to the presence of acrolein and formaldehyde (81). Toxicity of LLDPE pyrolysis products depends on temperature, heating rate, and the sample size (82—84). 

A method suitable for analysis of sulfur dioxide in ambient air and sensitive to 0.003—5 ppm involves aspirating a measured air sample through a solution of potassium or sodium tetrachloromercurate, with the resultant formation of a dichlorosulfitomercurate. Ethylenediaminetetraacetic acid (EDTA) disodium salt is added to this solution to complex heavy metals which can interfere by oxidation of the sulfur dioxide. The sample is also treated with 0.6 wt % sulfamic acid to destroy any nitrite anions. Then the sample is treated with formaldehyde and specially purified acid-bleached rosaniline containing phosphoric acid to control pH. This reacts with the dichlorosulfitomercurate to form an intensely colored rosaniline—methanesulfonic acid. The pH of the solution is adjusted to 1.6 0.1 with phosphoric acid, and the absorbance is read spectrophotometricaHy at 548 nm (273). 

If the compound causing the odor is known and can be chemically analyzed, it may be possible to get valid quantitative data by direct gas sampling. An example would be a plant producing formaldehyde. If the effluent were sampled for formaldehyde vapor, this could be related, through proper dispersion formulas, to indicate whether the odor would cause any problems in residential neighborhoods adjacent to the plant. 

Of these materials zein, the maize protein, has been used for plastics on a small scale. It can be cross-linked by formaldehyde but curing times are very long. Complicated bleaching processes have led to the production of almost colourless samples in the laboratory but the process cannot readily be extended to large-scale operation. The cured product has a greater water resistance than casein. Proteins from soya bean, castor bean and blood have also been converted into plastic masses but each have the attendant dark colour. 

BS ISO 16000 Indoor formaldehyde and other carbonyl compounds Active and diffusive sampling... 

When samples of about 1 cm were taken from a single cast film of 100 X 200 mm of a number of paint and varnish films, their resistances varied with the concentration of potassium chloride solution in one of two ways (Fig. 14.2). Either the resistance increased with increasing concentration of the electrolyte (inverse or / conduction) or the resistance of the film followed that of the solution in which it was immersed (direct or D conduction). The percentage of / and D samples taken from different castings varied, but average values for a number of castings were 50% D for the pentaerythritol alkyd and the tung oil phenol formaldehyde varnishes, 57% for urethane alkyd, 76% for epoxypolyamide and 78% for polyurethane varnishes... 

Various ionization methods were used to bombard phenol-formaldehyde oligomers in mass spectroscopic analysis. The molecular weights of resole resins were calculated using field desorption mass spectroscopy of acetyl-derivatized samples.74 Phenol acetylation was used to enable quantitative characterization of all molecular fractions by increasing the molecular weights in increments of 42. 

---