Hydrogen sulfite optical sensor based on a lipophilic guanidinium ionophore

Ibrahim H.A. Badr, Anadellys Plata, Pedro Molina, Mateo Alajarín, Angel Vidal, Leonidas G. Bachas

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


An optical chemical sensor is described for the sensitive and selective detection of hydrogen sulfite. The optode membrane is constructed by entrapping within a plasticized poly(vinyl chloride) membrane a hydrogen sulfite selective carrier (a lipophilic multicyclic guanidinium ionophore) and a proton chromoionophore (4',5'-dibromofluorescein octadecyl ester). Due to selective transport of hydrogen sulfite into the membrane by the guanidinium-based ionophore, protons are co-extracted into the polymeric membrane phase leading to a change in the ratio of the protonated and deprotonated form of the chromoionophore, and consequently a change in the absorbance value. The optode membrane shows a reproducible and reversible response toward hydrogen sulfite in the concentration range 0.02mM-0.1M in 50mM MES buffer, pH 5.5. In addition, the optode membrane is more selective toward hydrogen sulfite than other anions, including the more lipophilic anions (e.g., thiocyanate, perchlorate, iodide and nitrate). Copyright (C) 1999 Elsevier Science B.V.

Original languageEnglish (US)
Pages (from-to)63-69
Number of pages7
JournalAnalytica Chimica Acta
Issue number1-2
StatePublished - May 3 1999
Externally publishedYes


  • Absorbance
  • Analyte
  • Ionophore
  • Membrane
  • Sensor

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Environmental Chemistry
  • Spectroscopy


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