Formaldehyde vapor reagent

Fluorophors 57 Fluphenazine 104 Fluram 294 Folic acid 223,225 Formaldehyde reagent 299, 351 -, vapor reagent 86 Formazan 220... 

In the USA, the regulatory focus is on consumer and worker exposure to formaldehyde vapors released from the fabric, so the test method specified is AATCC Test Method 112-2003. In this method, 1 g of fabric is suspended over 50 ml of distilled water in a sealed quart jar. The jar is placed in an oven for either 4 h at 65 °C or 20 h at 49 °C. Any formaldehyde vapors generated are absorbed by the water. An aliquot of the formaldehyde-water solution is taken and analyzed colorimetrically using the Nash reagent.Typical levels of formaldehyde found in properly processed fabrics treated with modem cross-linking reagents are less than 100 ppm. The Nash method is based on the reaction of acetylacetone with formaldehyde and an ammonium salt to form a yellow complex with an absorbance maximum at 414 nm. The mild conditions of the reaction ( pH 7, 5 min at 58 °C) eliminate many potential interferences. 

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. 

Fluorescence stabilization, porphyrins la 100-101 Fluorophors la 57 Flupentixol lb 354 Fluphenazine la 104 lb 354-356 Fluspirilen lb 354 Fluvalinates lb 86 Foam bath, brominated la 64 Folic acid la 223,225 Folin-Ciocalteu s reagent lb 180 Folin s reagent lb 321 Formaldehyde la 299,351 -, vapor la 86 Formazan lb 65... 

Temperature and humidity is controlled to minimize evaporation of reagents and to keep performance of electronic equipment optimal. Ventilation is adequate for the removal of noxious fumes and odors. Formaldehyde and xylene vapor concentrations must be below maximum permissible levels. For formaldehyde, this level is 0.75 ppm for an 8-h time-weighted average, or 2.0 ppm for a 15-min short-term exposure. For xylene, the level is 100 ppm for an 8-h time-weighted average and 200 ppm for a 15-min short-term exposure. The monitoring of the work area and employees can be performed on a yearly basis. Chemical and biological safety cabinets are checked for proper airflow on a yearly basis. 

Although formaldehyde is inexpensive, readily available, highly reactive, and ideally would be the simplest ether cross-link between cellulose chains, there has been only limited successful usage of this reagent to produce wrinkle resistant cotton. A treatment based on gaseous- or vapor-phase application of formaldehyde to cotton under rigidly controlled conditions has gained some acceptance. 

Detection and Determination of Aldehyde. The amount of formaldehyde in methanolic reaction mixture was estimated quantitatively according to the procedure by Kolthoff (16). A series of solutions containing varying amounts (5 X 10" to 5 X lO M) of formaldehyde as well as the unknown sample, with pH adjusted to 3 by phosphate-citric acid buffer, was treated with 1.5 X lO M Schiff s reagent (3i). Thirty minutes later, the optical density at 5500 A. was determined by a Coleman Junior spectrometer. The unknown concentration of formaldehyde was estimated by interpolating the known values. This procedure was reproducible for autoxidation of ferrous chloride in methanol. However, in the presence of a reactive cosubstrate, such as benzoin, the color became unstable, and the analysis was only semiquantitative. It was possible to determine acetaldehyde quantitatively in ethanolic reaction mixtures by vapor chromatography using a decylphthalate column at 66°-68°C. 

In addition to iodine, other detection reagents (e.g., bromine, chlorine, formaldehyde, ammonia, diethylamine, HCl, sulfuryl chloride, sulfur dioxide, oxides of nitrogen, and ammonium bicarbonate) (see Section 11) can be applied as vapors. 

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