Fast and long term optical sensors for pH based on sol-gels

Enju Wang, Kwok Fan Chow, Vivian Kwan, Tammy Chin, Crystal Wong, Andrew Bruce Bocarsly

Research output: Contribution to journalArticlepeer-review

81 Scopus citations


Long lasting and fast response optical sensor for the detection of pH in the range of 6-12 is described. The sensor is fabricated by spin coating silica sol in the presence of phenol red (PR). The sol is in turn obtained by acidic hydrolysis of tetraethoxysilane (TEOS) and phenyltriethoxysilane (Ph-TriEOS). The performance of the sensor depends on the ratio of Ph-TriOES to TEOS. At the optimal composition, the sensor has a response time of less than 20 s, the response is completely reversible and its life-time is over 12 months.

Original languageEnglish (US)
Pages (from-to)45-50
Number of pages6
JournalAnalytica Chimica Acta
Issue number1-2
StatePublished - Oct 24 2003

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry
  • Biochemistry
  • Environmental Chemistry
  • Spectroscopy


  • Optical sensors, pH
  • Phenol red
  • Sol-gel
  • TEOS


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