Polymeric liquid membrane electrodes incorporated with macrocyclic hexaamines for screening adenine nucleotides

Lipophilic macrocyclic hexaamines supported by a poly(vinyl chloride) PVC m atrix were used for the construction of liquid membrane electrodes sensitiv e toward adenine nucleotide polyanions. The membrane potential strongly dep ended on the pH of the sample solution. This phenomenon occurs due to the a bility of the ionophore to accept protons. Therefore, the optimum pH was de termined based on potential-pH profile. The potential measurements were car ried out at pH 6.0 in the presence of 10(-2) M 2-[N-morpholino] ethanesulfo nic acid (MES) buffer. The potential response of these electrodes toward AT P(-) (4) and/or HATP(-3) was close to the Nernstian slope. The selectivitie s against ADP(-3), AMP(-2), HPO4-2 and monovalent inorganic anions were est imated using the matched potential method. Chloride ions slightly affected potential response of the electrodes toward ATP(-4)/HATP(-3). The influence of ionophore chemical structure on the selectivity and the sensitivity of these electrodes is briefly discussed.