A sample pre-treatment-free electrochemical immunosensor with negative electro-pulsion for the quantitative detection of acrylamide in coffee, cocoa and prune juice
Acrylamide is a potential carcinogen mainly found in heat-processed foods and its advised maximum intake is 2.6 μg kg−1 of body weight per day to prevent cancer risk; hence, a rapid detection method for acrylamide is strongly needed for food monitoring. In this study, a sample pre-treatment-free electrochemical immunosensor was developed via a displacement assay. The leaving of the anti-acrylamide antibody from the electrode surface is the predominant factor for an effective displacement assay. The dissociation rate of the antibody from the surface-bound hapten was enhanced by applying a negative electro-pulsion to the electrode surface. The pulsing duration and pulsing potential for the dissociation of the anti-acrylamide antibody were experimentally optimized. A three-level three-factorial Box–Behnken experimental design was employed in the present study to confirm the optimal displacement condition required based on a minimal experiment number (17 trials) without involving all possible experimental combinations. A linear dynamic range from 0.01 to 35.00 μg mL−1 was obtained, with the limit of detection (LOD) of 3.84 ng mL−1. The accuracy of the developed immunosensor was validated by using a standard method: gas chromatography-mass spectrometry (GC-MS). Moreover, the recoveries obtained from the spiked samples ranged between 90.33% and 99.23%. Hence, this method showed high selectivity and sensitivity for acrylamide determination in liquid food samples. Due to its simplicity of use, which excludes sample pre-treatment steps, this developed immunosensor has the potential to provide direct and quantitative acrylamide detection that is not significantly affected by food matrices.