Development of an isotope dilution liquid chromatography/tandem mass spectrometry detection method for DNA adducts of selected aromatic amines

Abstract

Polycyclic aromatic amines (arylamines) are a class of chemical carcinogens that are prevalent in environmental and industrial settings. They are metabolically activated to covalently bond to DNA, forming mutagenic adducts. In order to study the mechanisms of their toxicity, sensitive and selective quantitative LC/MS/MS detection methods were developed to measure the N-(adenin-8-yl)-benzidine adduct and N-(adenin-8-yl)-2-aminofluorene in total DNA extract samples. A novel synthetic method using a palladium catalyst was previously developed to prepare authentic and deuterated arylamine-adenine adducts to serve as standards. These standards were then used to develop an HPLC electrospray ionization tandem mass spectrometry, isotope dilution method. Sample detection limits in DNA samples were 22 pg on-column and 51 pg on-column for the N-(adenin-8-yl)-benzidine-and N-(adenin-8-yl)-2-aminofluorene-adenine adducts, respectively. This method has applications for the study of DNA adduct formation as a biological marker of exposure to carcinogens and for environmental and workplace monitoring of these aromatic amines. (J Am Soc Mass

Liquid chromatography-electrospray ionization-mass spectrometry: the future of DNA adduct detection

“…Typically the 14 N and/or 12 C atoms in purines or pyrimidines are substituted for 15 N and/or 13 C, respectively, resulting in a higher mass (106,117,123). Alternatively stable isotope internal standards containing deuterium atoms ( 2 H) replacing 1 H atoms can be used (165). However caution is required for their use due to the possible occurrence of exchange of the deuterium for hydrogen.…”

Analytical Aspects of Aromatic Amines

“…For example, adducts 33 and 34, formed on enzymatic condensation of benzidine (7b) and 1-aminofluorene (10a) with adenine residues of DNA, can be determined by tandem ESI-MS-MS analysis, following the fragmentations depicted in 105 and 106, which gives optimum intensities when operating under suitable conditions. Additional support for the assignments can be obtained from adducts derived from deuteriated 7b and 10a 28 . In the case of several isomeric compounds, yielding similar product ion spectra, two characteristics may be useful for identification of the analyte, with the help of a spectral database.…”

“…For example, adducts 33 and 34 can be isolated from DNA in tissues that have been exposed to mutagenic benzidine (7b) and 1-aminofluorene (10a), respectively. If the altered DNA is not repaired, it may lead to increased rates of sister chromatid exchanges, activation of the aromatic hydrocarbon receptors and ultimately to lung, bladder and skin cancer, transplacental transfer and premature ovarian failure 28 …”

Molecular Modeling Study of the Genotoxicity of the Sudan I and Sudan II Azo Dyes and Their Metabolites

“…They agreed with other findings that the C8 G position is the primary location of adducts due to its susceptibility to S N 2 nucleophilic attack. The C8 G starting 4-aminobiphenyl DNA adduct structure was based on mass spectrometry ( Means et al, 2003 ), although these were adenine rather than G adducts. The structure files in the sdf format for Sudan I (Solvent Yellow 14, C16H12N2O, CAS 842-07-9 1-Phenylazo-2-naphthalenol), Sudan II {Solvent Orange 7, C18H16N2O, CAS 3118-97-6, 1-[(2,4-Dimethyl Phenyl) azo]-2-naphthalenol}, azobiphenyl, and 4-aminobiphenyl were obtained and verified from both PubChem and ChemSpider.…”