Enzymatic biosensor for the electrochemical detection of 2,4-dinitrotoluene biodegradation derivatives

• Published in: Talanta (Oxford) Vol. 68; no. 5; pp. 1671 - 1676
• Main Authors: Rodríguez, Marcela C., Monti, Mariela R., Argaraña, Carlos E., Rivas, Gustavo A.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 28.02.2006; Oxford Elsevier
• Subjects: 2,4,5-Trihydroxytoluene; 2,4-Dinitrotoluene; 4-Methyl-5-nitrocatechol; Analytical chemistry; Biological and medical sciences; Biosensor; Biosensors; Biotechnology; Chemistry; Chromatographic methods and physical methods associated with chromatography; Electrochemical methods; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Glassy carbon paste; Methods. Procedures. Technologies; Other chromatographic methods; Polyphenol oxidase; Spectrometric and optical methods; Various methods and equipments; Glassy carbon paste; 4-Methyl-5-nitrocatechol; 2,4,5-Trihydroxytoluene; Biosensor; Polyphenol oxidase; 2,4-Dinitrotoluene; Electrochemical method; HPLC chromatography; Immobilization; Mineral oil; Polyphenol; Efficiency; Detection limit; Amperometry; Bacteria; Quantitative analysis; Biodegradation; Microsphere; Chemical sensor; Carbon; Enzymatic method; Sensitivity; Dinitrotoluene; Environment; Spectrophotometry
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2005.08.032

In this work, we demonstrate for the first time that 4-methyl-5-nitrocatechol (4M5NC) and 2,4,5-trihydroxytoluene (2,4,5-THT), two compounds obtained from the 2,4-DNT biodegradation are recognized by polyphenol oxidase as substrates. An amperometric biosensor is described for detecting these compounds and for evaluating the efficiency of the 2,4-DNT conversion into 4M5NC in the presence of bacteria able to produce the 2,4-DNT-biotransformation. The biosensor format involves the immobilization of polyphenol oxidase into a composite matrix made of glassy carbon microspheres and mineral oil. The biosensor demonstrated to be highly sensitive for the quantification of 4M5NC and 2,4,5-THT. The analytical parameters for 4M5NC are the following: sensitivity of (7.5 ± 0.1) × 10 5 nAM −1, linear range between 1.0 × 10 −5 and 8.4 × 10 −5 M, and detection limit of 4.7 × 10 −6 M. The sensitivity for the determination of 2,4,5-THT is (6.2 ± 0.6) × 10 6 nAM −1, with a linear range between 1.0 × 10 −6 and 5.8 × 10 −6 M, and a detection limit of 2.0 × 10 −7. Under the experimental conditions, it was possible to selectively quantify 4M5NC even in the presence of a large excess of 2,4-DNT. The suitability of the biosensor for detecting the efficiency of 2,4-DNT biotransformation into 4M5NC is demonstrated and compared with HPLC-spectrophotometric detection, with very good correlation. This biosensor holds great promise for decentralized environmental testing of 2,4-DNT.