• Atmospheric
  • National Oceanic and Atmospheric Administration (NOAA) Method NMFS-NWFSC-59 2004 is currently used to quantitatively analyze seafood for polycyclic aromatic hydrocarbon (PAH) contamination, especially following events such as the Deepwater Horizon oil rig explosion that released millions of barrels of crude oil into the Gulf of Mexico. (hindawi.com)
  • occurs
  • Benzopyrene is a component of pitch and occurs together with other related pentacyclic aromatic species such as picene, benzofluoranthenes, and perylene. (wikipedia.org)
  • structurally
  • They are structurally similar to other halogenated hydrocarbons such as polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs). (wikipedia.org)
  • rings
  • Many simple aromatic rings have trivial names. (wikipedia.org)
  • The nitrogen (N)-containing aromatic rings can be separated into basic aromatic rings that are easily protonated, and form aromatic cations and salts (e.g., pyridinium), and non-basic aromatic rings. (wikipedia.org)
  • Examples of basic aromatic rings are pyridine or quinoline. (wikipedia.org)
  • Examples of non-basic nitrogen-containing aromatic rings are pyrrole and indole. (wikipedia.org)
  • In the oxygen- and sulfur-containing aromatic rings, one of the electron pairs of the heteroatoms contributes to the aromatic system (similar to the non-basic nitrogen-containing rings), whereas the second lone pair extends in the plane of the ring (similar to the basic nitrogen-containing rings). (wikipedia.org)
  • main
  • The two main types are electrophilic aromatic substitution when the active reagent is an electrophile and nucleophilic aromatic substitution when the reagent is a nucleophile. (wikipedia.org)