A method to distinguish halide ions by using a Briggs-Rauscher reaction

Abstract

The current approach elaborates an innovative methodology for distinguishing four halide ions (F−, Cl−, Br− and I−) on their perturbation effects upon novel Briggs-Rauscher Reaction (BR) catalyzed by tetraaza-macrocyclic-nickel-complex (NiL)(ClO4)2. The lingand “L” in the complex is 5,7,7,12,14,14-hexamethyl-1,4,8,11 -tetraazacyclotetradeca-4,11-diene). Different oscillating profiles were exposed while the equal addition of four halide ions separately into active BR over the concentration range of 5.0 × 10−5-2.375 × 10−4 mol/L. Fluoride (F−) ion does not affect BR. Chloride (Cl−) ion could quench the potential oscillation at high potential and regenerate oscillation after a short inhibition time (tin). Bromide (Br−) ion could merely diminish the oscillation amplitude (A) and oscillation period (T) with no inhibition time whereas the iodate (I−) ion can restrain the potential oscillation at low potential and regenerate oscillation after a short inhibition time (tin). These four halide ions could be distinguished within 7 min. Cyclic voltammetry (CV) confirmed the redox reaction of potassium iodate with analytes while the bromination or the iodination products were testified by using mass spectrometry (MS) analysis after the perturbation of Br− or I−. Finally, a reasonable explanation of the perturbation mechanism for the BR was proposed based on well-known NF and FCA models.