Potentiometric FIA of trace phenol

A simple and rapid FIA of phenol is described, using bromination reaction and a Potentiometric detection. The detector is a combined electrode which consists of a bromide-selective electrode and a platinum electrode arrayed in series. The method is based on the measurement of potential changes in an initial stage of the bromination of phenol in a flow system. The sample is injected into a stream of carrier water and merged with a stream of acidic bromine solution which brominates phenol in the reaction tube. The amount of reduced bromine is determined by measuring the potential change with a Potentiometric detector, giving the concentration of phenol in samples. A linear relationship between peak heights and phenol concentrations is observed in the range of 5× 10-6 M to 2.5 × 10-5 - phenol. The relative standard deviation was 0.9% for analysis of 5× -0-6 - phenol at sampling rates of 80 h-1.