Development of an Analytical Method for Fast Detection of Residual Hydrogen Peroxide in Foods Based on Oxidative Etching of Avocado Seed Extract Capped With Gold Nanoparticles

A rapid hydrogen peroxide analytical method was developed in this study. The developed method incorporated gold nanoparticles (Au NPs) and potassium thiocyanate (KSCN) to improve residual hydrogen peroxide detection performance. Specifically, Au NPs were synthesized and then capped with avocado seed extract (ASE) to form spherical NPs (ASE‐Au NPs) with an average size of approximately 22 nm. The original sample solution color was reddish‐purple. However, when hydrogen peroxide was introduced to oxidize ASE‐Au NPs into ionic species in the presence of KSCN, the solution color gradually changed from reddish‐purple to pink and ultimately became colorless. Ultraviolet‐visible spectroscopy at a wavelength of 533 nm was used to analyze the color change caused by the hydrogen peroxide concentration. The limits of detection and quantification of the developed method were determined to be 6.06 and 20.19 ppm, respectively. The recovery rate of hydrogen peroxide was 90%. Based on these results, a test strip was developed that successfully detected residual hydrogen peroxide in hydrogen peroxide–spiked commercial noodles within 30 min.