Colorimetric Detection of Sulfite in Foods by a TMB–O2–Co3O4 Nanoparticles Detection System

• Published in: Journal of agricultural and food chemistry Vol. 62; no. 25; pp. 5827 - 5834
• Main Authors: Qin, Wenjie, Su, Li, Yang, Chen, Ma, Yanhua, Zhang, Haijuan, Chen, Xingguo
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 25.06.2014; American Chemical Society, Books and Journals Division
• Subjects: Benzidines - chemistry; Cobalt - chemistry; color; colorimetry; Colorimetry - instrumentation; Colorimetry - methods; detection limit; electron transfer; Food Analysis; Food Preservatives - analysis; foods; hydrogen peroxide; nanoparticles; Nanoparticles - chemistry; Oxides - chemistry; oxygen; Oxygen - chemistry; peroxidase; Sulfites - analysis; superoxide anion; colorimetry; oxidase mimic; mechanism of oxidase-like activity; sulfite; Co3O4 nanoparticles
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf500950p

In this paper, we first discovered that Co3O4 nanoparticles (NPs) possess intrinsic oxidase-like activity and can catalytically oxidize peroxidase substrates, such as 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) and 3,3′,5,5′-tetramethylbenzidine (TMB), to form colored products, in the absence of exogenously added H2O2. The presence of sulfite inhibited the TMB–O2–Co3O4 NPs reaction system and caused a change in color of the reaction system. On the basis of this phenomenon, a colormetric approach to detect sulfite was established with a good linear relationship ranging from 0.2 × 10–6 to 1.6 × 10–5 M and a detection limit of 5.3 × 10–8 M. The method was used to detect sulfite in foods. Good recoveries ranging from 93.8% to 100.5% were obtained. Furthermore, the mechanism was studied and results showed that the oxidase-like activity of the Co3O4 NPs was not from •OH or O2 •– radical generated. It may probably originate from their ability to transfer an electron between the peroxidase substrate and oxygen absorbed on the surface of the Co3O4 NPs.