Time-resolved fluorescent lateral flow strip for easy and rapid quality control of edible oil

Gutter oil is strictly prohibited from being reprocessed back to the catering and food industry. Extensive attention has been paid to rapid screening of gutter oil to guarantee the safety of edible oil. Capsaicin, a special component of condiments, has been adopted as the marker of gutter oil. The time-resolved fluorescent microspheres are utilized for labeling of antibody to capsaicin, which are further applied for the construction of fluorescent lateral-flow-strip (LFS). By simple extraction of capsaicin with ethanol (or liquor) from the edible oil, the capsaicin can be rapid determined with the fluorescent LFS in less than 10 min. As low as 20 ng/mL capsaicin can be visually judged and 2.3 ng/mL is achieved as the detection limit by ImageJ analysis. The illegal gutter oil is also well screened with this time-resolved LFS. This method can be a useful candidate for routine quality monitoring of edible oil and a powerful tool for self-inspection at home.