Trace Amounts Determination of Barium Ions by a New Ion-Selective Electrode based on 4ʹ,4ʺ(5ʺ)-Di-Tert-Butyldibenzo-18-Crown-6

A poly(vinyl chloride) membrane sensor for barium was prepared using 4ʹ,4ʺ(5ʺ)-Di-tert-butyldibenzo-18-crown-6 (DTB 18C6) as an ion carrier. The optimized membrane with PVC:DOP:DTB18C6:KTCPB percent ratio of 33:60:5:2 led to a Nernstian calibration slope of 25.23 mV per decade, from 1×10-7 to 1×10-1 M . Dioctyl phthalate was found to act as the best plasticizer in terms of controlling the response and durability of the sensor the lifetime of the fabricated sensor. The sensor had a short response time of 18 s and its response was independent from pH from 2.0 to 12.4 working pH ranges. The selectivity behavior of the sensor for barium in the presence of alkali, alkaline earth, transition and heavy metal ions was very good. The applicability of the sensor was evaluated through using it as an indicator in the potentiometric titration of SO42- ions.