Crown-Porphyrin Ligand for Optical Sensors Development

Larisa Lvova,Elisa Acciari,Federica Mandoj,Corrado Di Natale,Roberto Paolesse,Giuseppe Pomarico

doi:10.3390/proceedings2130922

Abstract

A novel porphyrin ligand, Zn(II)TPP-BPI-crown (ZnPC), functionalized with two dibenzo-crown-ether moieties was synthesized and tested as cation-sensitive ionophore. Fluorescence studies on ligand sensitivity towards a number of different metal cations (Na+, K+, Li+, Ca2+, Mg2+, Co2+, Cd2+, Pb2+, Cu2+, Zn2+ and NH4+) were carried out first in solution and then inside polymeric membrane optodes. Emission light signal was sufficiently brilliant to be captured by a low-cost computer webcam, while a commercial blue-light LED served as monochromic excitation light source. The influence on the ZnPC optode response of the lipophilic sites functionalization was investigated. The visibly (naked eye) observed color change of sensing material from green to red demonstrated the suitability of the ZnPC-based optodes to perform fast monitoring of Cu(II) ions in the concentration range between 6.6 × 10−7 and 2.4 × 10−2 mol/L with a low detection limit (estimated by s/n = 3 method) of 0.3 mg/L, which is lower than WHO guideline value of 2 mg/L.

Highlights

The development of novel sensing materials with analytically useful sensitivity toward metal cations for application in optical chemical sensors is nowadays a challenging task
Ionophores are key components that significantly contribute to the selectivity of polymeric membrane sensors
Less progresses were achieved in the development cationselective optodes, the response of which is dependent on ionophore-analyte interaction and luminescence variation upon complexation [2]

Summary

Introduction

The development of novel sensing materials with analytically useful sensitivity toward metal cations for application in optical chemical sensors is nowadays a challenging task. The use of compounds such as calix[n]arenes, crown-ethers, porphyrins or other ligands containing the cavity of determined size, has permitted previously to develop highly selective electrochemical sensors for cations [1].

Results

Conclusion