A novel colorimetric immunoassay based on enzyme-regulated instant generation of Turnbull's blue for the sensitive determination of ochratoxin A. Issue 6 (17th February 2020)

• Record Type: Journal Article
• Authors: Lai, Wenqiang; Guo, Jiaqing; Wu, Qingqing; Chen, Yaomin; Cai, Quanying; Wu, Luxi; Wang, Shuhan; Song, Jun; Tang, Dianping
• Is Part Of: Analyst. Volume 145:Issue 6(2020)
• Page Start: 2420
• Page End: 2424
• Publication Date: 2020-02-17
• Subjects: Chemistry, Analytic -- Periodicals; 543
• DOI: 10.1039/c9an02447f
• Languages: English
• ISSNs: 0003-2654

Abstract

Abstract : The aim of this study was to develop a novel colorimetric sensing method based on enzyme-regulated instant generation of Turnbull's blue, serving as a chromogenic agent, for a sensitive immunoassay for the determination of ochratoxin A (OTA). Abstract : The aim of this study was to develop a novel colorimetric sensing method based on enzyme-regulated instant generation of Turnbull's blue, serving as a chromogenic agent, for a sensitive immunoassay for the determination of ochratoxin A (OTA). Unlike the traditional enzyme-linked immunosorbent assay (ELISA), the chromogenic reaction reported herein relies on the immediate formation of Turnbull's blue. K3 [Fe(CN)6 ] rapidly forms a coordinate bond with iron(ii ), yielding a blue product. Meanwhile, glucose oxidase (GOx) catalyzes glucose hydrolysis to produce hydrogen peroxide (H2 O2 ), which was used to inhibit the formation of Turnbull's blue by oxidizing iron(ii ) to iron(iii ). Thus, Turnbull's blue was generated in an enzyme-regulated manner. Accordingly, a competitive-type colorimetric enzyme immunoassay was established using a GOx based nanolabel. Under optimal conditions, the absorbance increased upon increasing the target OTA concentration in the range of 0.01–10 ng mL −1 with a detection limit of 8.3 pg mL −1 estimated at the 3 S blank level. The assay accuracy was validated by analyzing spiked wine samples. The present results potentially provide novel insights into the development of Turnbull's blue-based biological detection methods and colorimetric immunoassay strategies.