Fabrication of a coated graphite electrode for selective determination of magnesium

In this project a mangnesium selective coated graphite electrode based on dibenzo-18-crown-6 as a neutral ionophore icorporated in polyvinyl choloride (PVC) membrane in tetrahydrofuran (THF) has been fabricated. The best operation obtained in the membrane including: 4.0 mg dibenzo-18-crown-6, 1.0 mg sodium tetraphenylborate (NaTPB), 65.0 mg dioctylphthalate (DOP) and 30.0 mg PVC. This electrode had a good selectivity respect to Mg2+ cation, with a nernstian slope of 29.1±0.7 mV.decade-1 in a linear concentration range of 1.0×10-1 M-1.0×10-5 M. The detection limit of the electrode was 8.9×10-6 M. The porposed sensor had a fast response time of 10 sec and good reproducibility. The effects of the pH and possible interfering ions were investigated, and it could be used in pH range of 3-12.

کلیدواژه ها:

Magnesium (II) cation ، Ion selective electrode ، Potentiometry