Dibenzo-18-crown-6 crown ether is found to exhibit quite promising selectiv
ity for Sr2+ ions. It can be used to estimate strontium in the range 5.0 x
10(-6) to 1.0 x 10(-1) mol dm(-3) (0.28 to 8.76 x 10(-3) mg dm(-3)) with a
near-Nernstian slope of 28 mV per decade of concentration. The working pH r
ange of the proposed sensor is 2.0-6.0 with a response time of 25 s. The se
nsor can be used for more than three months in aqueous as well as in partia
lly non-aqueous media. The practical utility of the membrane sensor has als
o been observed in solutions contaminated with detergent matter.