Copper is an essential trace element in the human body that plays a vital role in several physiological processes. In this study, binding constants and thermodynamic properties of the association of Cu2+ ions with two indigo derivatives, indigo carmine (IC) and potassium indigotrisulfonate (KItS), were determined via spectrophotometric analysis. Both indigo dyes selectively and spontaneously form 2:1 molar complexes with Cu2+ ions and do not form a complex with other metal (II) cations, specifically Mg2+, Ca2+, Cd2+ or Pb2+ in water or pH 10 buffer. The Cu2+-KItS complexation was found to be the most thermodynamically favored in water with an association constant K of 6.4 104 M-1. In addition, the Cu2+-IC complexation system in water or pH 10 buffer was determined to be the most sensitive chemosensor. The detection limits of aqueous Cu2+ ions were found to be 0.017 ppm while the quantification limits were estimated to be 0.058 ppm.

Spontaneous detection of Cu2+ ions in aqueous media using indigo derivative chemosensors

ACS Spring Meeting 2021

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