Formaldehyde detection estimation

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. 

The compound (III) can however lose ethanol by an internal Claisen ester condensation (p. 264) to give the cyclohexane derivative (IV), which, being the ester of a (3-keto acid, in turn readily undergoes hydrolysis and decarboxylation to give 5,5Hiimethyl cyclohexan-i,3Hiione (V) or Dimedone, a valuable reagent for the detection and estimation of formaldehyde. 

Detection and Estimation of Preservatives.—The antiseptics commonly tested for in meat are formaldehyde, formic acid, boric acid and fluorides. The analytical methods used for the detection of these and other antiseptics are given later (see Sausages). 

The same phenomenon was observed for mitraciliatine (10) and the closed ring E alkaloids 14-19, where the percentage metabolism by O-demethylation estimated by formaldehyde production ( 1%) was much less than the degree of total metabolism (25-69%). Nevertheless, both hirsutine and mitraciliatine gave detectable amounts of a compound assumed by TLC analysis to be an 0-(17)-demethyl metabolite, whereas such was not the case with 14-19. Hirsutine and mitraciliatine were also metabolized (to unidentified products) by both rat and guinea pig liver microsomes, which did not metabolize alkaloids 4-6, 9, and 11-13. 

Descriptions of methods for the estimation or detection of morphine and/or codeine in urine,213-218 body fluids,219 blood,220 blood stains,221 hair,222 and opium,223 for the examination of illicit heroin,224-226 and for the estimation of dihydromorphinone in plasma227 have been published, the effect of formaldehyde on the estimation of morphine has been examined,228 and a bioassay for morphine and naloxone has been described.229... 

Methyl alcohol may be detected and estimated by conversion to methylaniline by means of iodine, phosphorus and aniline, followed by oxidation by stannic chloride to methyl violet. Other methods depend upon the conversion of the methyl alcohol to formaldehyde, which gives various colour reactions, with morphine sulphate and with fuchsine bisulphite. 

Formaldehyde-specific IgE antibodies could be detected in only 1/86 serum samples from four groups of formaldehyde-exposed subjects (Kramps et al. 1989). The groups included 28 subjects living or working in places with formaldehyde-containing construction materials (e.g., chipboard) and estimated formaldehyde concentrations ranging from 0.08 to 0.37 ppm, 18 occupationally exposed subjects from an anatomy laboratory and in other unspecified industries where air concentrations were not measured,... 

Formaldehyde-specific IgE was not detected in a group of 45 medical students, before or after the students attended a 4-week anatomy dissecting course (Wantke et al. 1996b). Estimates of laboratory air concentrations of formaldehyde ranged from 0.059 to 0.219 ppm (mean 0.124 0.05 ppm). Surveys revealed frequencies of irritation symptoms consistent with other studies (e.g., itching of the skin in 33/45 students, headache in 15/45, and burning eyes in 13/45). 

Weak P hyperfine interactions to the desulfo inhibited, formaldehyde inhibited and rapid type I (formamide) Mo(v) species have been detected by CW X-band ENDOR spectroscopy. The hyperfine components could be estimated by performing the experiments at various fields across the entire envelope of 7 = 0 Mo(v) EPR features. The value of the A component was determined to be in the 0.15-0.17 MHz range for all these species while that of the Ax was estimated to be 0.1 MHz. A Mo to P distance of -7-12 A could be estimated from evaluation of the dipolar component of the hyperfine interaction using a simple point dipole approximation. This interaction was attributed to the phosphate group of the pterin cofactor. Similar conclusions were obtained from analysis of the ENDOR spectra given by the low-pH chloride Mo(v) signal of cSO. ... 

Spectrophotometric detection Polyols can be determined by estimating the formaldehyde produced after mild periodate oxidation using arsenic(III) oxide... 

Gas samples from room air were also detected with PTR-MS to estimate the indoor air quality [4,123]. Samples were taken from five rooms constructed more than 20 years ago. Two rooms had been equipped with new furniture and carpets only 2 months before the measurements were done. The concentrations of formaldehyde and ethanol were quite similar in the old and newly furnished rooms. Acetaldehyde, methanol, propanol, acetone, and toluene were strongly enhanced in the two newly furnished rooms. It was also found that the concentration of formaldehyde in four of the five rooms was higher than the maximum concentration allowed by Austrian law for permanent exposure dose to human [4]. 

Small quantities of methyl alcohol in ethyl alcohol may be detected and estimated by a method based upon that of Georgia and Morales, in which methyl alcohol is oxidised to formaldehyde and formic acid, ethyl alcohol to acetaldehyde the method is as follows ... 

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