Determination of p -Dimethylaminobenzaldehyde by Using a Briggs–Rauscher Electrochemical Oscillator

We introduced a novel technique for monitoring the activity of analytes for the first time. The technique is built upon the inhibitory effect caused by the free-radical-scavengers on the pattern of novel Briggs–Rauscher (BR) electrochemical oscillator catalyzed by tetra-aza-macrocyclic complex catalyst ([NiL](ClO 4 ) 2 . The ligand “L” in the complex is 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene. The effect involves a sudden ceasing of oscillation, an inhibition time ( t in ) that directly proportional to the amount of additive ( p -Dimethylaminobenzaldehyde ( p -DMAB)) added, and subsequent restoration of oscillations. Thus, a linear regression curve between concentrations range of 2.7 × 10 –7 mol L –1 to 4.5 × 10 –6 mol L –1 p -DMAB Vs t in was achieved with a correlation coefficient of 0.98. The observed limit of detection (LOD) is 2.7 × 10 –7 mol L –1 while the RSD calculated from 7 measurements of 2.5 × 10 –6 mol L –1 p -DMAB is 1.5%. Factors that influence the determination of p -DMAB were also studied. The mechanistic interpretation of the perturbed oscillation was anticipated from both NF and FCA models. A fleeting elucidation is that the intermediate species (HOO • ) produced during oscillatory reactions and reacted with p ‑DMAB. As a result, the oscillation was temporarily ceased.