English

Abstract

Phenolic compounds are commonly employed as preservatives, disinfectants, pesticides, herbicides, insecticides, dyes and medical and industrial organic raw chemicals. These chemicals are present in the environment as a result of different manufacturing activities of the petrochemical, resin and plastic, pharmaceutical, antioxidant and paper and pulp industries, among others. They are mostly recalcitrant pollutants that accumulate over time and are found in potable water, sediments and soil. Furthermore, some phenolic compounds are widely known due to its toxicity and potential carcinogenic and mutagenic activity. Chlorophenols , which are the main degradation products of many chlorinated phenoxy acids, are one example of these hazardous compounds. The US Environmental Protection Agency (EPA) has listed 11 phenolic compounds as priority pollutant. Moreover, the European Union has set the maximum total and individual phenol allowed concentration in water used for human consumption at 0.5 mg/L and 0.1 mg/L, respectively. However, as phenols are hardly degraded by traditional water treatment processes, their concentration in drinking water usually exceeds the allowed concentration. Conventional analytical methods for these compounds, such as spectrophotometry, HPCL and GC-MS and their variations, are extensive as they require several analytical procedures to obtain accurate results. The analysis of phenols in water is normed by EPA methods. These time-consuming and cost-intensive methods required large sample amounts for the extraction and use of large volumes of toxic organic solvents. Therefore, current developments in the field aim for fast and low-cost measuring methods. The resulting environmental concern creates a demand for the development of reliable, sensitive simple and cost-effective methods for fast detection of phenolic compounds. Consequently, enzymatic-based biosensors have grown as a promising technology in the detection field. Enzymes are the most widely used biological sensing element in the fabrication of biosensors . The major advantages of biosensors are high sensitivity, specificity, and applicability to multi component solutions in situ . This chapter seeks to give an overview of the developed techniques that can be applied to the analysis of phenolic compounds in environmental water samples. The principles of the electrochemical biosensors based on enzyme-catalyzed chemical reactions for phenolic compounds determination are studied in this segment. Redoxenzymes, such as tyrosinase-, peroxidase- and laccase-based biosensors have proven to be very useful for the determination of phenols and substituted phenols at low concentrations. The recent trends in the advancement of electrochemical biosensor for phenolic compounds quantification, including nanomaterials transducer modification, are also reviewed.