Highly Selective Determination of Perchlorate by a Calix[4]arene based Polymeric Membrane Electrode

This article describes a versatile application of 25,27-bis-N-(N,N-diethyl-2-aminoethyl)carbonylmethoxy-26,28-dihydroxycalix[4]arene (4) as an ionophore for the preparation of perchlorate ion-selective electrode. The electrode exhibits a Nernstian response over the perchlorate concentration range of 1.0x10(-9) - 1.0x10(-1) M with a slope of 59.24 +/- 0.5mV per decade of the concentration. The limit of detection as determined from the intersection of the extrapolated linear segments of the calibration plot is 3.04x10(-9) M. The electrode shows good selectivity toward perchlorate with respect to many common anions. The response time of the sensor was 5-10s and it has maximum life time of 2 months in the acidic pH. The electrode was used to determine perchlorate in real water samples. The interaction of the ionophore with perchlorate ions is also demonstrated by UV-vis spectroscopy.