title: A neutral carrier-based liquid membrane microelectrode for divalent putrescine cations.
abstract: A new ion-selective liquid membrane microelectrode, based on the neutral carrier 1,1'-bis(2,3-naphtho-18-crown-6), is described that shows the dependence of EMF on the activity of divalent putrescine cations a(Put), with the linear slope s(Put) = 26 +/- 3 mV/decade (mean +/- SD, N = 18), in the range 10(-4)-10(-1) M at 25 +/- 1 degrees C. Values of potentiometric putrescine cation selectivity coefficients of logK(Pot)(Put) (j) (mean +/- SD, N) are obtained by the separate solution method for the ions K(+) (1.0 +/- 0.4, 10), Na(+) (-1.2 +/- 0.4, 8), Ca(2+) (-2.3 +/- 0.5, 10) and Mg(2+) (-2.5 +/- 0.5, 7). The microelectrode can be applied for the direct analysis of the activities of free divalent putrescine cations in the range 5 x 10(-4) to 10(-1) M in an extracellular ionic environment. Established analytical methods, e.g. high performance liquid chromatography, determine the total concentration of the derivatives of free and bound putrescine.
authors.affiliation: Max-Planck-Institut für Biophysik, Kennedyallee 70, D-60596 Frankfurt am Main, Germany. drouin@biophys.mpg.de
authors.forename: H R
authors.initials: HR
authors.lastname: Drouin
mesh_terms: D002413:Cations, Divalent / Q000032:analysis*; D004563:Electrochemistry / Q000379:methods; D004573:Electrolytes; D008567:Membranes, Artificial; D008839:Microelectrodes; D011700:Putrescine / Q000032:analysis*
chemical_list: D002413:Cations, Divalent; D004573:Electrolytes; D008567:Membranes, Artificial; D011700:Putrescine