Detection of heavy metals by an optical fiber sensor with a sensitive cladding including a new chromogenic calix[4]arene molecule

Industrial processes introduce up to a million different pollutants into the atmosphere and the aquatic ecosystem. Heavy metals are one group of these substances, although not all of them are considered harmful to humans. The molecule of calixarene is a macrocycle used effectively in the complexation of the heavy metal pollutants (nickel, copper(II)…). The goal of this work is to condition a new chromogenic calix[4]arene molecule to elaborate an optical fiber sensor able to detect this type of pollutant. The light power increases when the concentration of the ion increases. The optimum pH for heavy metal ion detection is found to be 5. The influence of the unclad length on the response sensor is studied and the optimum length is found to be around 3 cm. The limit of detection reached is of the order of 1 μM, 10 − 3 μM and 10 − 4 μM for copper(II), cobalt(II) and cadmium(II) cations respectively.