Natural deep eutectic solvent-based QuEChERS followed by magnetic beads ELISA for the analysis of ochratoxin A in cereal samples

Herein, we established a green, rapid, and sensitive method to analyze ochratoxin A (OTA) in cereals based on modified QuEChERS and enzyme-linked immunosorbent assay (ELISA). Lignocellulose is a renewable material mainly consisting of cellulose, hemicellulose, and lignin. In the modified QuEChERS, a natural deep eutectic solvent synthesized from glucose and levulinic acid derived from cellulose and hemicellulose was used as an extraction solvent to replace traditional organic solvents. Furthermore, modified lignin was used as an adsorbent to purify the extraction solution. In the magnetic bead-based ELISA, the effervescent reaction accelerated the immune competition. Additionally, magnetic beads were used to shorten the incubation and washing time, whereas gold nanoparticles were used to amplify the optical signal. This method has been successfully applied to the analysis of OTA in cereal samples. The limits of detection were 0.68-0.83 mu g kg(-1). This pretreatment and detection strategy has potential application in analyzing mycotoxins.