Sub-micro level monitoring of beryllium ions with a novel beryllium sensor based on 2,6-diphenyl-4-benzo-9-crown-3-pyridine

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 29.6 mV per decade) over a very wide concentration range (1.0 x 10(-7) to 1.0 x 10(-1)) With a detection limit of 4.0 x 10(-8) M (360 pg ml(-1)). It shows relatively fast response time, in whole concentration range (< 10 s), 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. (C) 2004 Elsevier B.V. All rights reserved.