GREEN-SYNTHESIZED GOLD NANOPARTICLES SUPPORTED ON CELLULOSE NANOWHISKERS FOR EASY-TO-INTERPRET COLORIMETRIC DETECTION OF CADMIUM (II)

In the present study, we report on a simple and practical optical sensor based on cellulose nanowhiskers functionalized with gold nanoparticles (CNW/AuNP), which was applied as a colorimetric sensor for detecting Cd (II). Our results revealed that a simple and fast synthesis was capable to produce small and well-controlled CNW/AuNP nanocomposites. These nanocomposites can bind to Cd (II), owing to the citrate anions present on the AuNP surface, and this process is followed by an optical change in the surface plasmon resonance (SPR) band of AuNPs. As a consequence, a linear decrease of absorbance was verified as the Cd (II) concentration increased in the range 500-2000 nM, yielding a detection limit of 60 nM. Our sensor also proved to be suitable for real samples analyses, even in the presence of other interfering substances, indicating its potential for Cd (II) colorimetric sensing applications.