Liquid chromatography system with an enzyme biosensor for measurement of phenolics

摘要

Because phenolic compounds are difficult to measure, even under laboratory conditions, relatively simple and inexpensive methods for screening these compound sin the field can be of considerable value in remediation of phenolics-contaminated sites. Enzyme-based amperometric sensors using polyphenol oxidase have been shown to measure certain of these compounds. This enzyme is particularly stable to high concentrations of organic media allowing it to be incorporated into liquid chromatogrphy systems. Reverse-phase high performance liquid chromatography with dual electrode detection was used to measure phenolic compounds. The carbon paste electrode which contained 3percent tyrosinase was held at a potential of -0.2 V and yielded a stable response to phenol, p-methoxyphenol, p-cresol and p-chlorophenol. The signal from the plain carbon paste electrode (held at a potential of +1.0 V) was less stable and degraded by 50percent after several consecuitive injections. In contrast to the complex gas chromatogram for an extract of a mixture of phenols spiked into soil, the tracing for the HPLC with the tyrosinase electrode detector was relatively simple and detected only phenol and p-cresol.