NITRITE-SELECTIVE MICROELECTRODES

The development of nitrite-selective liquid membrane microelectrodes b ased on a synthetic charged ionophore is described. The addition of po tassium tetrakis(4-chlorophenyl)borate and poly(vinyl chloride) to the membrane phase is essential to lower the ohmic resistance and to prol ong the lifetime of the microelectrodes. The detection limits for sodi um nitrite solutions without and with an ion background of 0.1M chlori de are 10(-5.1) and 10(-4.2) M, respectively. The comparison with macr oelectrodes shows that the miniaturization reduces, to some extent, th e selectivity and the slopes of the EMF response functions.