Immobilization of Tyrosinase on Cu Nanostructures Thin Film as a Potential Tool for Catechol Detection

Catechol, a common environmental pollutant and a by-product of many industrial processes, poses a potential threat to the ecosystem and human health. Therefore, the accurate and sensitive detection of catechol is of paramount importance for a wide variety of scientific studies and industrial applications. Immobilized tyrosinase is a valuable tool for facilitating the development of potential phenolic detection applications. This study performed the immobilization of tyrosinase on Cu nanostructures thin film (tyrosinase/Cu NSs-TF) for catechol detection and investigated the optimum working conditions. The successful immobilization process was determined using Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The optimum pH and temperature for tyrosinase/Cu NSs-TF were 7.0 and 30°C, respectively. Concerning the reusability of tyrosinase/Cu NSs-TF, it retained over 73% of its activity after the first two replicates and 51.67% after the sixth replicate. When the storage stability of tyrosinase/Cu NSs-TF was investigated at 4°C, it was found that 52.42% of the initial activity was retained until the seventh day. A spectrophotometric method was used for catechol detection. Tyrosinase/Cu NSs-TF displayed a linear response to the concentrations of catechol in the range of 2-90 µM. The limit of detection (LOD) and limit of quantification (LOQ) were calculated to be 7.73 µM and 25.76 µM, respectively. A recovery study was performed with tap water spiked with catechol at concentrations of 30 µM, 60 µM, and 90 µM, yielding recovery rates of 104.44%, 99.58%, and 101.53%, respectively. The results show that tyrosinase/Cu NSs-TF may be a promising approach for catechol detection in water.