Aromatic amines, assay

Chemical methods for folic acid detection are not useful for unfractionated biologic materials (H16). Reduction of folic acid in acid yields a methylpteridine and N-(p-aminobenzoyl) glutamic acid. The latter is estimated by a method for aromatic amines (B33). Another assay method of historical interest is the growth of chicks as a measure of the folic acid content of crude biological mixtures. 

Solvent-free conditions were used by Tanaka et al. in their assays to obtain intermolecular reactions from alkynes and anilines. The chosen catalyst was [AuMe(PPh3)] with an acidic promoter [92]. Reaction, whose effectiveness was greater in the case of aromatic amines, proceeded via Markovnikov by amine electrophilic attack of the alkyne in a similar way to the methanol addition proposed by Teles (see Section 2.1.3.2) and provided high yields and TONs. 

Amine and Aminophenol Derivatives. Amines and aminophenols (Table VIII) react with the F-C reagent about as predicted considering the aromatic amino groups equivalent to phenolic hydroxyls. This would be an important interference with total phenol assay in samples with appreciable aromatic amine content. Fortunately, for this and other reasons as well, the major wine grapes and most other fruit and vegetable products are free of significant concentrations of aromatic amines which would interfere. Correction might be made for methyl anthranilate... 

Greene and Shimizu [77] have reported a displacement assay using a colorimetric dye f/V,/V-dimethyI-/V./V-("7-nitro-2.1,3-benzoxadiazol-4-yl)-l, 2-ethanediamine) with absorption maximum at 460 nm. This assay allowed the determination of seven different aromatic amines. Nevertheless, although the dye seems to be more sensitive in the polymer than in solution, after thorough optimization of the assay conditions, the displacement is only significant for the mmol L 1 amine concentration range. 

Silver sulfadiazine is dissolved in dilute hydrochloric acid and determined by titration with sodium nitrite solution (assay of the primary aromatic amine function). The endpoint detection is commonly biamperometric (27). 

High levels of retinol or retinyl acetate inhibit mutagenicity induced by aromatic amines in a Salmonella/mammalian microsome assay when carcinogen activation is carried out by S9 or purified microsomes ... 

In addition to the rodent bioassay, the aromatic amines have been studied in the shorter term test Salmonella typhimurium mutagenicity as well as in a variety of acute toxicity assays. A number of QSARs have been generated from such data. The work of Hansch in recent years has demonstrated that the comparison of the QSAR models obtained in different systems, by putting them in a wider perspective, can provide useful clues in the study of the mechanisms of action of individual chemical classes, and can give precious hints on how appropriate the specific models and parameters selected are (Hansch, 2001 Hansch et al., 2002). An exercise of the mechanistic comparison of QSARs has been performed on aromatic amines (Benigni and Passerini, 2002). The results are detailed below. 

G. Kalopissis, Mutat. Res., 246, 45 (1991). Structure-Activity Relationships of Aromatic Amines in the Ames Salmonella typhimurium Assay. 

Assay 5=85% total coloring matters as the sodium salt Organic compounds other than coloring matters <0.5% Unsulfonated primary aromatic amines <0.01% as aniline Ether-extractable matter <0.2% under neutral conditions Accessory colorings <1.0%... 

The presence of mutagens such as nitroarenes and aromatic amines in environmental waters or industrial effluents can be assessed by the Ames test and in vitro cytogenetic assay for bacteria (outside the scope of this chapter), involving a combination of toxic... 

An indirect electrochemical method developed for nitrite determination may be of general applicability for PAA determination, as shown in equation 13. A nitrite sample is placed into a cell containing a known amount of 3-sulfanilic acid in dilute HC1 at pH 3. After 5 min the diazonium ion formation is complete an excess of catechol (109) is added and the concentration of the remaining 3-sulfanilic acid is determined at +0.12 V with a GCE vs. standard calomel electrode, by measuring the adduct (110) formed between the aromatic amine and the quinone derived from catechol in the diffusion layer of the electrode. The 3-isomer of sulfanilic acid was chosen among the three isomers, aniline and 4-nitroaniline for its highest sensitivity and its lowest LOD, 0.7 pM, with linearity from 20 to 80 pM. A spectrophotometric assay may be carried out for nitrite by measuring at 516 nm the azo dye derived from catechol and the diazonium ion after 3 h ... 

Certain aromatic amines may cause reduction of Fe(III) ions in the presence of Fer-roZine Iron reagent (125), according to equation 18, leading to the formation of a stable violet-colored complex with Fe(II) ions (126), the concentration of which is measured at 562 nm. At pH 5, the color develops in a few minutes at room temperature and the absorbance of 126 is proportional to the concentration of the analyte. Neither the oxidation products of the analyte nor the excess of Fe(III) or 125 affect the assay however, not all aromatic amines undergo this reaction. Thus, compounds such as 1,4-phenylenediamine, 2,4-diaminotoluene, 8-aminoquinoline and 2-amino-3-hydroxypyridine can be determined... 

A major drawback of redox-based assays is that any oxidizable compound in the sample solution will react, too. Ascorbic acid, sulphur dioxide (in wines), aromatic amines and carbohydrates (production of endiol reductones in alkaline solution) are the most frequently encountered reductants [47,106]. 

Of all the short-term assays, the Ames Salmonella test is clearly the best validated and most widely used and will continue to be so for a number of years to come. The assay has an excellent record for identifying organic carcinogens, particularly carcinogens which are in the aromatic amine and polycyclic hydrocarbon classes. " In addition, positive results in the Ames assay and several other short-term mutagenesis assays, have been predictive of carcinogenic activity in rodent assays for a number of compounds with widespread human exposure. Examples of these include the food preservative furylfuramide AF-2 which was used extensively in Japan from 1965 to about 1977 the flame-retardant tris-B-P (tris[2,3-dibromopropyl]phosphate) which was used to treat children s sleepwear from 1972 to 1977 and aromatic amine components of hair dye preparations. 

Water soluble 7-substituted quaternary anunonium salt derivatives of 10,11 -(methylenedioxy) - and 10,11 -(ethylenedioxy)-(20S)-camptothecin 216 (Figure 9) are synthesized via the Friedlander reaction followed by nucleophilic displacement with an aromatic amine. All are more potent than camptothecin in the in vitro cleavable complex assay (96JME713). 

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