Ag-nanozyme as peroxidase mimetic for colorimetric detection of dihydroxybenzene isomers and hydroquinone estimation in real samples

Abstract

Ag-Nanozyme (AgNZ) was fabricated by simple reduction method using Piper pedicellatum (PP) extract where catechin is the major constituent. The prepared PP-AgNZ acted as a nanozyme (NZ) that could catalyze the oxidation of TMB substrate in presence of H2O2 leading to a color reaction at an optimal time of 30 min at 45 °C. The enzyme mimic activity of PP-AgNZ showed a significant Km value of 0.0636 mM for TMB. Dihydroxybenzene (DHB) isomers could interrupt the oxidation process of TMB leading to the fading of the blue color into distinct intensities each for CA, HQ, and RE. This study reports a simple preparation of NZ used for reliable colorimetric detection of trace amounts of DHB isomers employing very simple technique. The detection was achieved for a linear range of 10–270 nM for CA and RE and, 10–390 nM for HQ. The limit of detection was found to be very low i.e. 32.38 nM, 30.64 nM, and 37.5 nM for CA, HQ, and RE respectively. Further, the detection of HQ was also supported by smartphone-assisted sensing to show the accessibility and applicability of our approach. Our work also demonstrated its effectiveness when applied to real environmental samples, yielding remarkable recovery rates ranging from 91.4 % to 108.6 %. Thus, the synthesized PP-AgNZ stands out as a promising NZ for its applications in environmental chemistry.