Preparation of gold nanoparticles-bacterial cellulose nanopaper and its application as 2D-microcuvette for spectrophotometric determination of hydrogen peroxide

Abstract

This work presents a new method development using the gold nanoparticles (AuNPs)-bacterial cellulose (BC) nanopaper for the spectrophotometric determination of hydrogen peroxide (H2O2). The AuNPs were embedded in the BC nanopaper, where the nanopaper played two roles as both the reducing agent and the template for the as-prepared AuNPs. The preparation process was started by putting the wet bare BC nanopaper (Ø 30 mm and 3 mm thickness) into 0.75 mmol L-1 HAuCl4 (25.0 mL). This solution was vigorously and continuously stirred for 60 min at 90ºC. After the embedding process, color of the nanopaper was changed from milky-white to wine-red. The AuNPs-BC nanopaper was characterized by UV-visible spectrophotometer, FE-SEM and EDS. Absorption spectrum of the nanopaper showed the characteristic peak of Au0 at 525 nm. The amount of 97.3 weight % of Au0 was found. The spectrophotometric assay was carried out by dropping the aliquots of 100 µL of sample and 400 µL of 20 mmol L-1 citrate buffer (pH 6.0) onto the AuNPs-BC nanopaper. The nanopaper was then kept in a plastic back for 10 min. In the presence of H2O2, the wine-red color of the AuNPs-BC nanopaper was turned to pale red accordingly to reduction of Auo to Au(III) by H2O2. Decreasing in the absorbance of the nanopaper at 525 nm was monitored using UV-visible spectrophotometer. Detection limit (yB + 3SB) of 0.79 % (v/v) was observed and this value was enough sensitive for the determination of H2O2 in wound cleaner and hair dye samples. The H2O2 contents in all samples were agreed well with the label values. Good analytical recovery (88.8 to 97.2 %) with high precision (RSD: 3.3 %) were obtained. These results confirmed that the as-prepared nanopaper was successfully synthesized and was effectively applied as the two dimensional (2D)-microcuvette for the spectrophotometric determination of H2O2 in real samples.