Journal of Fluorescence

, Volume 12, Issue 2, pp 263–268 | Cite as

Potassium Sensing by Using a Newly Synthesized Squaraine Dye in Sol-Gel Matrix

  • Kadriye ErtekinEmail author
  • Berrin Yenigül
  • Engin U. Akkaya


Squaraines are a group of fluorescent dyes and pigments derived from squaric acid and dialkylanilines well known in applications such as photoreceptors, organic solar cells, optical recording media, and non-linear optics. Their very promising spectral properties, long wavelength absorption and emission, and high absorptivity and quantum yields have not been exploited so far in relation to optical sensor design. They exhibit excellent solubility in sol-gel matrices, and the ligand is an integral part of the fluorophore π system, which makes the molecule a fluoroionophore. In this work, potassium-sensing agent, bis[4-N-(1-aza-4,7,10,13,16-pentaox acyclooctadecyl)-3,5-dihydroxyphenyl] squaraine has been used for potassium sensing in a sol-gel matrix. The spectrofluorimetric response of dye-doped tetraethyl ortosilicate (TEOS) film after exposure to certain concentrations of K+ has been investigated, and 62% of relative signal change was achieved. The dynamic working range of the sensor membrane has been found between 10−9 and 10−6 M K+, in other terms from nanomolar to micromolar levels, which is an advantage over flame emission spectroscopy, in view of detection limit. The sensor is fully reversible within the dynamic range and the response time (τ90) is found to be 2 min under batch conditions. The cross-sensitivity of the molecule to Na+, Ba2+, Ca2+, and NH+4 was also tested in separate solutions.

Optical potassium sensing squarine structure sol-gel matrix 


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Copyright information

© Plenum Publishing Corporation 2002

Authors and Affiliations

  • Kadriye Ertekin
    • 1
    Email author
  • Berrin Yenigül
    • 1
  • Engin U. Akkaya
    • 2
  1. 1.Department of Chemistry, Faculty of ScienceEge University, BornovaIzmirTurkey
  2. 2.Department of ChemistryMiddle East Technical UniversityAnkaraTurkey

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