Benzo pyrene hydrocarbons, polycyclic

Benzo(a)anthracene under Polycyclic Aromatic Hydrocarbons, Four-Ring Compounds Benzo(a)pyrene under Polycyclic Aromatic Hydrocarbons, Five-Ring Compounds Benzo(fc)fluoranthene under Polycyclic Hydrocarbons, Nonaltemant Compounds with Five Fused Rings... 

Colpa et al. (1963) calculated p/ (S )-values for a series of aromatic hydrocarbons, but could not detect fluorescence changes in the regions of acidity indicated by the Forster cycle, although fluorescence spectra attributed to proton complexes of 3,4-benzo-pyrene and 1,2-benzanthracene were observed in some solutions containing only the neutral molecule in the ground state. Flurry and co-workers (1963, 1966, 1967) have carried out theoretical and Forster cycle calculation on the excited state basicities of poly-methylbenzenes and Kuz min et al. (1967) have also calculated p/sT(S1)- and p7 (T )-values for polycyclic aromatic hydrocarbons increases in base strength of from 7 to 30 powers of ten were derived for Sj. 

At low temperatures, in situations where there is relatively little 02, pyrolysis reactions (i.e. reactions where decomposition takes place as a result of heat) may cause a rearrangement of atoms that can lead to the formation of polycyclic aromatic hydrocarbons (see Section 2.7) during combustion. The most notorious of these is benzo[ ]pyrene (B[ ]P see Fig. 2.4), a cancer-inducing compound. 

Polycyclic aromatic hydrocarbons DMBA (dimethylbenzanthracene), BaP (benzo[ ]pyrene), MCA (methylcholanthrene) ... 

Being interested here in the volatile components of coffee aroma, we shall arbitrarily limit the list of the aromatic hydrocarbons to tricyclic structures. The higher fused polycyclic hydrocarbons (fluoranthene [206-44-0], pyrene [129-00-0], chrysene [218-01-9], benz[ ]anthracene (1,2-benzanthracene) [56-55-3], benz[< ]acephenanthrylene (3,4-benzofluoranthene) [205-99-2], benzo[ ]pyrene (3,4-benzopyrene, 3,4-BP) [50-32-8], benzo[e]pyrene (1,2-benzopyrene) [192-97-2], perylene [198-55-0], benzo[g,/i,/]perylene (1,12-benzopyrene) [191-24-2], and dibenz[ ,//]anthracene (1,2,5,6-dibenzanthracene) [53-70-3]) cannot be considered as a part of the aroma. However, as some of these, specially benzo[o pyrene, are known for carcinogenic properties, they have been particularly analyzed in food subject to roasting or smoke-curing. 

Benz[fl]anthracene (see Polycyclic Aromatic Hydrocarbons) Benzo[h]fluoranthene (see Polycychc Aromatic Hydrocarbons) Benzo[y]fluoranthene (see Polycyclic Aromatic Hydrocarbons) Benzo[fc]fluoranthene (see Polycyclic Aromatic Hydrocarbons) Benzo[fl]pyrene (see Polycyclic Aromatic Hydrocarbons) Benzotrichloride Bromodichloromethane... 

The benzo(a)pyrene analogous polycyclic hydrocarbon chrysene is also metabolized stereospecifically into the corresponding epoxide metabolites [67]. The mutagenicity [68, 69] and tumorigenicity [70, 71] of the chrysene-l,2-dio-3,4-epoxide-1 and -2 diastereoisomers are well known. Wood et al. [72] studied the enantioselective toxicities of the four isomers of chrysene-l,2-dio-3,4-epoxide - that is, the -1 and -2 and chrysene-H4-3,4-epoxides (Figure 4.9) - in bacterial and mammal cells. The authors studied... 

A large number of polycyclic aromatic hydrocarbons are known Many have been synthesized m the laboratory and several of the others are products of com bustion Benzo[a]pyrene for example is present m tobacco smoke contaminates food cooked on barbecue grills and collects m the soot of chimneys Benzo[a]pyrene is a carcinogen (a cancer causing substance) It is converted m the liver to an epoxy diol that can induce mutations leading to the uncontrolled growth of certain cells... 

Polycyclic aromatic hydrocarbons have been classified as human carcinogens because they induce cancers in experimental animals and because smoking and exposure to mixtures of chemicals containing polycyclic aromatic hydrocarbons in the workplace increase the risk of lung cancer in exposed individuals. In experimental animals, benzo(a)pyrene induces cancer in different organs depending on the route of administration.Furthermore, exposure to polycyclic aromatic hydrocarbons commonly occurs in occupations related to traffic (use of diesel engines in transportation and railways). 

Fig. 42 Chromatogram of polycyclic aromatic hydrocarbons on caffeine-impregnated precoated silica gel 60 HPTLC plates with concentrating zone (Merck). The following can be recognized in increasing Rf value. — 1. benzo(ghi)perylene, 2. indeno(l,2,3-cd)pyrene, 3 benzo(a)pyrene, 4. benzo(b)fluoranthene, 5. benzo(k)fluoranthene, 6. fluoranthene.

Figure 3 depicts profiles of Total PAH fluxes vs. time (36). The following polycyclic hydrocarbons have been determined by high performance liquid chromatography, variable wavelength absorption detection Naphthalene, acenaphthylene, 7,12-dimethylbenzanthracene, 2-methylnaphtalene, fluorene, acenaphtene, phenanthrene, 2,3-dimethylnaphtalene, anthracene, fluoranthene, 1-methylphenanthrene, pyrene, 2,3-benzofluorene, triphenylene, benz(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, perylene, benzo(e)pyrene, 1,2,3,4-dibenzanthracene, benzo(a)pyrene, and 1,2,5,6-dibenzanthracene. 

Benzo[a]pyrene, a molecule with five, fused, hexagonal rings, is among the most carcinogenic of the polycyclic aromatic hydrocarbons (PAHs). Such biological activity may be related to the electronic structure of benzo[a]pyrene and its metabolites. Ionization energies of these molecules therefore have been investigated with photoelectron spectroscopy [28]. 

Warshawsky D, T Cody, M Radike, R Reilman, B Schumann, K LaDow, J Schneider (1995) Biotransformation of benzo[a]pyrene and other polycyclic aromatic hydrocarbons and heterocyclic analogues by several green algae and other algal species under gold and white light. Chem-Biol Interact 97 131-148. 

Juhasz AL, R Naidu (2000) Bioremediation of high molecular weight polycyclic aromatic hydrocarbons a review of the microbial degradation of benzo[a]pyrene. Int Biodet Biodeg 45 57-88. 

Sander and wise have proposed a test method to determine the bonding chemistry used to prepare octadecylsiloxane column packings based on the relative retention of three polycyclic aromatic hydrocarbons, benzo[a]pyrene (BaP), phenanthro-phenanthrene (PhPh), and l,2 3,4 5,6 7,8-tetrabenzonaphthalene (TBN) eluted with the mobile phase acetonitrile-water (85 15) [52,67,199,210]. On monomeric phases the test solutes elute in the... 

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