A simple, azulene-based colorimetric probe for the detection of nitrite in water

Lloyd C. Murfin, Carlos M. López-Alled, Adam C. Sedgwick, Jannis Wenk, Tony D. James, Simon E. Lewis

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We describe the synthesis and evaluation of an azulene-based chemodosimeter for nitrite. The probe was found to undergo two distinct color changes upon introduction of aqueous nitrite ion. A near-instant formation of a grey color provides a qualitative indication of the presence of nitrite, followed by the formation of a deep-yellow/ orange color, the endpoint from which quantitative data can be derived. The azulene probe exhibits 1:1 stoichiometry of reaction with nitrite in water, and is selective for nitrite over other anions. The azulene probe was applied to determine nitrite content in cured meat, and compared with the British Standard testing procedure (Griess test). The value obtained from the azulene-based probe agreed closely with the standard test. Our procedure only requires the preparation of one standard solution, instead of the three required for the standard Griess test.

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 665992
Original languageEnglish
Pages (from-to)90-96
Number of pages7
JournalFrontiers of Chemical Science and Engineering
Issue number1
Early online date22 Mar 2019
Publication statusPublished - 1 Feb 2020


  • azulene
  • diazoquinone
  • nitrite

ASJC Scopus subject areas

  • General Chemical Engineering


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