A synthesized bis(dibenzoylmethanato)Co(II) complex (Co(DBM)(2)), has been used as a ionophore for the preparation of a new perchlorate ion-selective electrode. The electrode exhibits a Nernstian response over the perchlorate concentration range of 8.0 x 10(-7) -1.0 x 10(-1) M with a slope of 60.3 +/- 0.5 mV per decade of concentration. The limit of detection as determined from the intersection of the extrapolated linear segments of the calibration plot is 5.6 x 10(-7) M. The electrode shows good selectivity towards perchlorate with respect to many common anions. The response time of the sensor is very fast (<= 5 5), and can be used for at least 2 months in the pH range of 2.0-9.0. The electrode was used to determine perchlorate in water and human urine. The interaction of the ionophore with perchlorate ions was demonstrated by UV-vis spectroscopy. (C) 2008 Elsevier B.V. All rights reserved.