Determination of Phenols in Environmentally Relevant Matrices with the Use of Liquid Chromatography with an Enzyme Electrode Detector

A simple and rapid assay using HPLC with a tyrosinase-containing carbon paste electrode (Tyr-CPE) detector is demonstrated for the detection of phenol, p-cresol, p-methoxyphenol, and p-chlorophenol in environmental matrices. These compounds were measured in contaminated aqueous soil leachate samples or acetone/acetonitrile extracts of soil and sludge samples. The dynamic range for this assay was 2-30 ppm for phenol and p-cresol. In addition to analysis by the Tyr-CPE detector held at a reducing potential (-0.20 V), soil leachate and extracts were analyzed with the use of a carbon paste electrode (CPE) detector at oxidizing potentials (+1.0 V or +1.2 V). Compared to the CPE, the Tyr-CPE detector was very stable, showing a signal loss of only 28% over 24 h of continuous operation. In addition, the signal from the CPE degraded rapidly by 65% over 10 sequential injections, whereas the signal of the Tyr-CPE decreased by only 5% for the same number of sequential injections. Because of the minimal sample preparation for analysis of soil leachate samples, the herein-reported Chromatographic system with biosensor detector could be further developed to complement portable tyrosinase enzyme electrode biosensors that detect total phenols in field settings.