Detection of Acrylamide in Foodstuffs by Nanobody-Based Immunoassays

Acrylamide is toxic aliphatic amide formed via the Maillard reaction between asparagine and reducing sugars during thermal processing of food. Herein, a specific nanobody termed Nb-7E against the acrylamide derivative xanthyl acrylamide (XAA) was isolated from an immunized phage display library and confirmed to be able to detect acrylamide. First, an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) was established for acrylamide with a limit of detection (LOD) of 0.089 mu g/mL and working range from 0.23 to 5.6 mu g/mL. Furthermore, an enhanced electrochemical immunoassay (ECIA) was developed based on the optimized reaction conditions. The LOD was as low as 0.033 mu g/mL, threefold improved compared to that of ic-ELISA, and a wider linear detection range from 0.39 to 50.0 mu g/mL was achieved. The average recoveries ranged from 88.29 to 111.76% in spiked baked biscuits and potato crisps. Finally, the analytical performance of the ECIA was validated by standard ultraperformance liquid chromatography tandem mass spectrometry (UPLC-MS/MS).

Automated summary

A specific nanobody Nb-7E against acrylamide was isolated and confirmed to be able to detect acrylamide. An ic-ELISA and an ECIA were developed for acrylamide determination, with ECIA showing lower limit of detection and wider linear detection range.