Potentiometric Graphite Coated Electrode Based on Ditertbutyl-cyclohexano18crown6 for Detection of Strontium (II) Ions

In this work, a highly sensitive strontium ion selective polymer membrane coated on a graphite electrode based on ditertbutylcyclohexano18crown6 as ionophore is described. The sensor responds to strontium ions in a linear concentration range of 10-5 - 10-1 M with a Nernstian slope of 29.1 ± 0.3 mV/decade and a detection limit of 4.0×10-6 M in the pH range of 3.0 - 10.6. It has a fast response time of less than 10 s and can be used for at least 5 months without any considerable divergence in its potentials. The proposed sensor revealed good selectivity for strontium ions with respect to other cations and was used as an indicator electrode in the potentiometric titration of strontium ions with EDTA and also in the determination of strontium ions in binary mixtures and different real samples.