Development of a highly sensitive and selective electrochemical immunosensor for controlling of rhodamine B abuse in food samples

Here, a highly sensitive and selective electrochemical immunosensor was established for the rapid screening of Rhodamine B (Rh B) in paprika and capsicol. Rh B complete antigen was prepared and used as immunogen to obtain anti-Rh B monoclonal antibody (anti-Rh B-mAb) through cell fusion technology. A layer of cobalt hydroxide and gold nanoparticles composite material (Co(OH) 2 –Au NPs) was modified on the surface of screen-printed electrode (SPE) by one-step electrodeposition. Subsequently, Rh B antigen was coated on the modified SPE as coating antigen, then Rh B and anti-Rh B-mAb labeled with cerium oxide (anti-Rh B-mAb@CeO 2 ) were overlay simultaneously. Rh B can compete with the Rh B coating antigen to combine the anti-Rh B-mAb which causing electrical signal changes. After optimization of the assembled immunosensor, the assay showed a linear range when the concentration of Rh B ranged from 0.01 ng/mL to 10000 ng/mL. The average recovery rate of spiked samples was 85.7%∼106.8%, which was in good accordance with the standard HPLC determination. The immunosensor behaves high sensitivity and selectivity, and can be used in the rapid screening of Rh B in paprika and capsicol.