Nanobiosensing of phenol and its derivatives in a Kraft synthetic black liquor

Phenol is an important raw material in the manufacturing industry, and it is found in industrial streams, both as a by-product and in wastewater flows. Due to their toxicity, the presence of phenol and its derivatives in water resources influences the quality of natural water, causing negative effects on human life. Thus, easily accessible measurement tools for phenol could be made available in rural communities where access to technology is limited. Sensors offer this opportunity, as they provide fast, reliable and easy use. In this study, a colorimetric nanobiosensor was developed based on polydiacetylene (PDA) liposomes, functionalized with Horseradish peroxidase (HRP).The recognition element was the HRP enzyme, immobilized at the surface of a cell-like nanostructure; biological interaction HRP-phenol was detected and the colorimetric PDA present  in the liposome acted as a transducer element. After biological interaction, the polymer backbone is transformed from the blue to red phase; this colorimetric transition is observed visually and registered spectrometrically. The nanobiosensor was used to detect the phenol concentration in the 0.25 to 2 mM range in an industrial stream from the Kraft process, simulated under lab conditions. The response of the biosensor gives 7 % error in comparison with a spectrometric method.