Identification Formaldehyde

The testing of impnrities in active pharmacentical ingredients has become an important initiative on the part of both federal and private organizations. Franolic and coworkers [113] describe the utilization of PLC (stationary phase — silica gel and mobile phase — dichloromethane-acetonitrile-acetone (4 1 1, v/v)) for the isolation and characterization of impurities in hydrochlorothiazide (diuretic drug). This drug is utilized individually or in combination with other dmgs for the treatment of hypertension. The unknown impurity band was scraped off the plate and extracted in acetonitrile. The solution was filtered and used for LC/MS and NMR analysis. The proposed procedure enabled the identification of a new, previonsly nnknown impurity. It was characterized as a 2 1 hydrochlorothiazide-formaldehyde adduct of the parent drug substance. 

Metz B, Kersten GFA, Hoogerhout P, et al. Identification of formaldehyde-induced modifications in proteins reactions with model peptides. J. Biol. Chem. 2004 279 6235-6243. 

Recently, Vasilescu et al. demonstrated the use of formaldehyde to preserve protein interactions in vivo followed by immunoaffinity purification of a targeted complex, cross-link reversal via heating at 95°C, separation by SDS-PAGE, and identification of bands by LC-MS/MS.7 Tagwerker et al. utilized formaldehyde cross-linking in conjunction with a novel tag-based affinity purification method.36... 

Toews J, Rogalski JC, Clark TJ, et al. Mass spectrometric identification of formaldehyde-induced peptide modifications under in vivo protein cross-linking conditions. Anal. Chim. Acta. 2008 618 168-183. 

Clearly some molecular processing occurs in the coma to produce larger molecules such as methanol, formaldehyde and more complex still, but the detection and identification of bigger molecules are limited by the sensitivity and resolution of the instruments. The inventory, however, is probably a guide to an untold story... 

Attention should be paid to the appearance of spurious peaks in the fragmentation patterns of amines determined by GC-MS, when the analytes came into contact with methanol or ethanol as solvents. Thus, for example, Schiff bases may be formed on condensation of a primary amine with traces of formaldehyde or acetaldehyde present in the solvent. Although the peaks of such product may be unresolved in the chromatogram, they may appear as ions with mass increments of +12 or +26 in the mass spectrogram, complicating the identification of the analyte, as was the case with some amphetamine drugs99. 

Li, C Domen, K Maruya K Onishi, T. Spectroscopic identification of adsorbed species derived from adsorption and decomposition of formic acid, methanol, and formaldehyde on cerium oxide, J. Catal, 1990, Volume 125, Issue 2, 445-455. 

Formalin is an aqueous solution of approximately 40% formaldehyde. It was traditionally used to preserve biologic specimens, but its identification as a mild carcinogen has curtailed its use as a preservative. Formaldehyde is widely used to produce synthetic resins. Resins are sticky, liquid organic compounds that are insoluble in water. They often harden when exposed to air. Many commercial types of glue are resins. Natural resins are produced by plants as a response to damage. When a plant suffers external damage, natural resins flow to the area and harden to protect the underlying... 

Pitts, J. N., Jr., H. W. Biermann, E. C. Tuazon, M. Green, W. D. Long, and A. M. Winer, Time-Resolved Identification and Measurement of Indoor Air Pollutants by Spectroscopic Techniques Nitrous Acid, Methanol, Formaldehyde, and Formic Acid, J. Air Pollut. Control Assoc., 39, 1344-1347 (1989). 

Arnts, R. R and S. B. Tejada, 2,4-Dinitrophenylhydrazine-Coated Silica Gel Cartridge Method for Determination of Formaldehyde in Air Identification of an Ozone Interference, Environ. Sci. Technol., 23, 1428-1430 (1989). 

California Air Resources Board, Final Report on the Identification of Formaldehyde as a Toxic Air Contaminant, Sacramento, CA, 1992b. 

Because the rate is independent of vessel size in the presence of mercury vapor, and inert diluents decrease the rate (1), it is concluded that initiation and termination are gas phase, and peroxides are destroyed at the wall in mercury free systems. A more detailed understanding of the mechanism of formaldehyde oxidation requires quantitative consideration of peroxides such as performic acid, and unequivocal evidence for the identification of chain carriers. 

Standard hydrographic data (temperature, salinity, fluorescence and inorganic nutrients) were generally recorded continuously. Chlorophyll a concentrations of discrete samples were determined fluorometrically. Water samples were preserved with Lugol s iodine solution and 0.5% neutralised formaldehyde for onshore identification and enumeration of the phytoplankton using an inverted microscope. 

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