Differential dynamic potentiometric responses obtained with anion-selective electrodes for perchlorate, thiocyanate, iodide, nitrate, sulfate, picrate and bis(trifluoromethylsulfonyl) imide

Abstract

Differential dynamic potentiometric (DDP) responses for perchlorate, thiocyanate, iodide, nitrate and sulfate as inorganic anions, and picrate and bis(trifluoromethylsulfonyl) imide, a common ionic liquid anion, as organic anions are presented. DDP signals were obtained as the difference between the individual potential responses displayed by two anion-selective electrodes, one containing a membrane with β-cyclodextrin (β-CD) as anion-ionophore and the other containing a similar membrane without β-CD (blank membrane). Highly reproducible DDP signals characteristic for each anion were obtained. Principal components (PC) analysis applied to the DDP responses permitted differentiation of the anions assayed. Additionally, a linear relationship was found between the PC1 values of each anion signal and the corresponding values of an anion lipophilicity descriptor. Finally, the DDP technique was extended to the study of some anion mixtures.