Transformation of Acetaminophen by Chlorination Produces the Toxicants 1,4-Benzoquinone and N-Acetyl-p-benzoquinone Imine
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- 作者：Mary Bedner and William A. MacCrehan
- 刊名：Environmental Science & Technology
- 出版年：2006
- 出版时间：January 15, 2006
- 年：2006
- 卷：40
- 期：2
- 页码：516 - 522
- 全文大小：137K
- 年卷期：v.40,no.2(January 15, 2006)
- ISSN：1520-5851
文摘
The reaction of the common pain reliever acetaminophen(paracetamol, 4-acetamidophenol) with hypochloritewas investigated over time under conditions that simulatewastewater disinfection. Initially, the reaction wasstudied in pure water at neutral pH (7.0), a range ofreaction times (2-90 min), and a molar excess of hypochlorite(2-57 times) relative to the acetaminophen concentration.The reaction was monitored using reversed-phaseliquid chromatography (LC) with ultraviolet absorbance,electrochemical, and mass spectrometric detection. At1 
mol/L (150 ppb) and 10 mol/L (1.5 ppm) levels,acetaminophen readily reacted to form at least 11discernible products, all of which exhibited greater LCretention than the parent. Two of the products wereunequivocally identified as the toxic compounds 1,4-benzoquinone and N-acetyl-p-benzoquinone imine (NAPQI),which is the toxicant associated with lethality in acetaminophen overdoses. With a hypochlorite dose of 57 mol/L(4 ppm as Cl2), 88% of the acetaminophen (10 mol/Linitial) was transformed in 1 h. The two quinoidal oxidationproducts 1,4-benzoquinone and NAPQI accounted for25% and 1.5% of the initial acetaminophen concentration,respectively, at a 1 h reaction time. Other products thatwere identified included two ring chlorination products, chloro-4-acetamidophenol and dichloro-4-acetamidophenol,which combined were approximately 7% of the initialacetaminophen concentration at 1 h. The reaction wasalso studied in wastewater, where similar reactivity wasnoted. These results demonstrate that acetaminophen is likelyto be transformed significantly during wastewaterchlorination. The reactivity of the chlorine-transformationproducts was also studied with sulfite to simulatedechlorination, and 1,4-benzoquinone and NAPQI werecompletely reduced.
mol/L (150 ppb) and 10 mol/L (1.5 ppm) levels,acetaminophen readily reacted to form at least 11discernible products, all of which exhibited greater LCretention than the parent. Two of the products wereunequivocally identified as the toxic compounds 1,4-benzoquinone and N-acetyl-p-benzoquinone imine (NAPQI),which is the toxicant associated with lethality in acetaminophen overdoses. With a hypochlorite dose of 57 mol/L(4 ppm as Cl2), 88% of the acetaminophen (10 mol/Linitial) was transformed in 1 h. The two quinoidal oxidationproducts 1,4-benzoquinone and NAPQI accounted for25% and 1.5% of the initial acetaminophen concentration,respectively, at a 1 h reaction time. Other products thatwere identified included two ring chlorination products, chloro-4-acetamidophenol and dichloro-4-acetamidophenol,which combined were approximately 7% of the initialacetaminophen concentration at 1 h. The reaction wasalso studied in wastewater, where similar reactivity wasnoted. These results demonstrate that acetaminophen is likelyto be transformed significantly during wastewaterchlorination. The reactivity of the chlorine-transformationproducts was also studied with sulfite to simulatedechlorination, and 1,4-benzoquinone and NAPQI werecompletely reduced.