Aromatic amine residue

UK Ministry of Agriculture Fisheries and Food and Flealth and Safety Executive, Annual Report of the Working Party on Pesticide Residues in Food (1997), MAFF Publications, London, 1997. lARC, Monographs on the Evabiation of the Carcinogenic Risk of Chemicals to Hnmans Volume 56 Some Naturally Occurring Substances Food Items and Constituents, Heterocyclic Aromatic Amines and Mycotoxins, WFIO, Geneva, 1979, p. 397. 

Primary aromatic amines (e.g., aniline) and secondary aliphatic-aromatic amines (e. g., 7V-methylaniline) usually form triazenes in coupling reactions with benzenedi-azonium salts. If the nucleophilicity of the aryl residue is increased by addition of substituents or fused rings, as in 3-methylaniline and 1- and 2-naphthylamine, aminoazo formation takes place (C-coupling). However, the possibility has also been noted that in aminoazo formation the initial attack of the diazonium ion may still be at the amine N-atom, but the aN-complex might rearrange too rapidly to allow its identification (Beranek and Vecera, 1970). 

Example 5. Glycolysis of Polyurethanes with Propylene Oxide after Pretreatment with Ethanolamine.55 A rigid polyurethane foam (ca. 100 g) was dissolved in 30 g ethanolamine by heating. Excess ethanolamine was stripped, leaving a clear solution. Infrared and GPC analysis indicated that the clear solution obtained contained some residual polyurethane, aromatic polyurea, aliphatic polyols, aromatic amines, and N,N -bis(f -hydroxyethyljurea. Next the mixture was dissolved in 45 g propylene oxide and heated at 120°C in an autoclave for 2 h. The pressure increased to 40 psi and then fell to 30 psi at the end of the 2-h heating period. The product was a brown oil with a hydroxyl number of485. 

Aromatic amine-containing haptens are converted to diazonium salts with ice-cold nitrous acid. Diazonium salts can then react with a protein at alkaline pH (around 9) through electrophilic attack of the diazonium salt at histidine, tyrosine and(or) tryptophan residues of the carrier protein (Table 7). 

Residual color due to autoxidation of 4-aminophenol (one of 4-PAP s constituent aromatic amines)... 

Two experiments were conducted to study the utility of HPLC in determining aromatic amines in commercial dyes. In the first experiment a benzidine based dye, Direct Blue 6, and a commercial hair dye formulation containing Direct Blue 6 were analyzed for benzidine. In the second experiment a DCB based pigment (diarylide yellow) was analyzed for residual DCB. 

The compounds of the particle phase are collectively called tar, or total particulate matter (TPM). Tar is the oily residue left behind when moisture evaporates from burned tobacco. It contains thousands of compounds, including cancer-causing aromatic amines, nitro-samines, and polycyclic aromatic hydrocarbons that are present in both smoking and smokeless tobacco. Other harmful constituents include radioactive lead and polonium as well as arsenic, among others. 

Coupling Components With Condensed Cyclic Ammo nium Residues. Heterocyclic compounds in which the condensed benzene ring is substituted by a hydroxyl or an amino group can be coupled with diazonium compounds and may also be quatemized, either prior or subsequent to the coupling reaction, to yield cationic azo dyes. l,2-Dialkyl-6-nitroindazolium salts are reduced to the 6-amino compounds and then coupled with diazonium salts of aromatic amines. These dyes (e g., 21) color polyacrylonitrile in bright yellow to orange shades [64],... 

The modulation of mutagenicity of aromatic amines in Salmonella is not a result of (a) PCB treatment of rats, or the presence of residual PCB s in liver preparations, (b) vagaries of the Salmonella plate test, or (c) the effect of retinoids upon bacterial viability. 

Molecules which are not electrochemically active can be derivatized using an appropriate "electrophore", making the derivative eligible for electrochemical detection (9). It is fortunate that the nitrophenyl group, commonly used for UV and GC derivatization, is easily reducible. Methods based on the determination of intact carbamate residues by GC have been very disappointing as the result of thermal instability of a large majority of carbamate compounds. Therefore, a number of derivatization methods have been proposed. Carbamates, which produce an aromatic amine or phenol when hydrolyzed, were derivatized using 2,4-Dinitrofluorobenzene (DNFB) to form 2,4-... 

Aromatic amines may be converted to their diazonium salts with nitrous acid. The hapten may then be bound via azo linkages to the tyrosine (shown), histidine, lysine, and possibly arginine and tryptophane residues of the carrier protein by mixing the... 

It is known that CYP1A2 preferentially binds molecules with a relatively planar moiety, with heterocyclic aromatic amines, xanthines and quinolones. It is also likely that surface amino acid residues are responsible for the recognition of and the selectivity towards specific ligands [11]. 

Where the template has been an aromatic amine of low basidty, interaction with carboxylic acid groups has proved too weak to allow selective imprinting. However, Sherrington et al. [112] have shown that the sulphonic add residue in 2-acrylamido-2-methylpropane sulphonic acid is very useful under these circumstances the much higher acidity of this add allows protonation of the weak base template, and hence sufficiently strong electrostatic interaction for imprinting to be achieved. 

Much of Landsteiner s pioneer work was carried out with haptens that were aromatic amines. The compounds were converted to diazonium salts with nitrous acid and aUowed to react with proteins at alkaline pH (approximately 9). Reaction occurred primarily with histidine, tyrosine, and tryptophan residues of the protein carrier. For a representative procedure, see Kabat (p. 799 seq.). An interesting application of this procedure was the preparation of a chloramphenicol-protein conjugate which was used to elicit antibodies specific for chloramphenicol. In this case, a prior reduction of the nitro group of chloramphenicol to an amino group was required. As early as 1937, carcinogenic compounds were conjugated to protein carriers by means of their isocyanate derivatives which were prepared from amines. Immune sera were raised, and their properties were studied. - ... 

Cleaning Up The residues from the distillation of 1,2-phenylenediamine and the solvent from the reaction should all be placed in the aromatic amines hazardous waste container since the diamine may be a carcinogen. 

In this chapter, the role of LC-MS in various aspects of food safety analysis is discnssed. LC-MS is important in the quantification and confirmation of identity of food contaminants, e.g., residues of pesticides and related substances in frait and vegetables (Ch. 7.7), antibiotic and antibacterial compounds, other veterinary dmgs, anabolic steroids, and various toxins in feed and food. In addition, attention is paid to the analysis of heterocychc aromatic amines in food. 

Aromatic amines undergo condensation with fluorescamine (93), presumably according to equation 7, to yield fluorescent products (94). The process was applied to derivatize PAA mixtures prior to determination by MEKC with FLD (Section IV.C)189,190. This derivatizing procedure was used for detection of unreacted isocyanate residues in the... 

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