Evaluation and reduction of matrix effect by deep eutectic solvents in lateral flow assays: A case study for zearalenone detection in different food matrices

The food samples with high-fat content could induce matrix effects and interfere with the accuracy of lateral flow immunoassays (LFA), while deep eutectic solvents (DESs) as the innovative extraction solution had great potential to decrease this effect by rational design. First, 24 samples were evaluated for the detection performance of LFA using zearalenone (ZEN) as the target, and we found that black sesame, pecan, cashew, and pistachio with high-fat content could seriously affect recoveries and limit of detection (LOD), generating high matrix effects. To address this issue, six DESs with different polarities were designed by arrangement of two hydrogen bond donors and three hydrogen bond acceptors. DES-4, composed of betaine and ethylene glycol with a molar ratio of 1:4, displayed a lower molecular polarity index, which was similar to ZEN and possessed significant differences with fatty acids. Subsequently, DES-4 was applied to LFA for ZEN detection in these four high-fat matrices. After centrifugation, 70.5 %-92.3 % of fat in food matrices was transferred to the upper layer, and the fat content of the detection phase and food matrices phase by DESs extraction was 77.0–290.2 mg, obviously lower than that by acetonitrile/water extraction. Moreover, the recoveries ranged from 82.01 % to 114.26 % after diluting 50–70 times, and the LODs were 1.72–4.06 ng/mL, which were 1.4–4.6 times lower than that of acetonitrile/water extraction. Hence, DESs were considered as promising extraction reagents to reduce the high fat-induced matrix effects, which may be broadened to other target detection.