RESUMO
The 2,6-diphenyl-4-benzo-9-crown-3-pyridine (DPCP) was used as an excellent ionophore in construction of a coated graphite poly(vinyl chloride) (PVC)-based membrane sensor. The best performance was obtained with a membrane composition of 30% poly(vinyl chloride), 60% o-nitrophenyloctyl ether (NPOE), 5% 2,6-diphenyl-4-benzo-9-crown-3-pyridine and 5% sodium tetraphenyl borate (TBP). This sensor shows very good selectivity and sensitivity towards beryllium ion over a wide variety of cations, including alkali, alkaline earth, transition and heavy metal ions. The sensor revealed a great enhancement in selectivity coefficients and sensitivity for beryllium, in comparison with the previously reported beryllium electrodes. The electrode exhibits a Nernstian behavior (with slope of 29.6mV per decade) over a very wide concentration range (1.0x10(-7) to 1.0x10(-1)) with a detection limit of 4.0x10(-8)M (360pgml(-1)). It shows relatively fast response time, in whole concentration range (<10s), and can be used for at least 12 weeks in the pH range of 4.5-8.0. The proposed sensor was successfully used to determination of beryllium in mineral ore.
