A Rapid Fluorescence Sensor for the Direct Quantification of Rongalite in Foodstuffs

Abstract

Rongalite was reported illegally used as a food additive for bleaching purposes and improving the tenderness of foodstuffs, which may endanger public health. At present, rongalite was mostly detected by indirect methods via derivatization or determining its decomposition products. In this study, we developed a new fluorescence sensor for the direct quantification of rongalite based on the principles: (1) dopamine reacts with resorcinol and generates strong fluorophore (azamonardine); (2) rongalite could inhibit the production of fluorophores and then result in lower fluorescence intensity. Hence, the rongalite concentration was inversely proportional to fluorescence intensity of fluorophore. Several crucial reaction conditions of fluorescence sensor were further optimized, such as dopamine and resorcinol concentration, pH values, and reaction time. Under the optimal conditions, the limit of detection of fluorescence sensor was 0.28–0.38 μg/g in vermicelli, wheat and rice powder samples, exhibiting almost 3.5-fold improvement compared to that of lateral flow immunoassay. Moreover, the detection time was substantially decreased to 20 min. The recoveries in spiked samples were 80.7–102.1% with a coefficient of variation of less than 12.6%. In summary, we developed a direct, high throughput, selective and accurate fluorescence sensor that poses a promising application for the rapid detection of rongalite in foodstuffs.

Optical Sensing of Toxic Cyanide Anions Using Noble Metal Nanomaterials

“…Metal nanoparticles have been involved in optical sensing platforms, including those based on colorimetry [ 27 , 28 ], surface plasmon resonance [ 41 , 42 , 43 , 44 ], fluorescence [ 45 , 46 , 47 ], RS [ 48 ], and SERS tactics [ 49 , 50 ]. These sensing devices have produced reasonably good sensitivity in detecting analytes with adequate specificity, whereas the high reproducibility of the sensor signals remains a challenge due to limited control over the uniformity of nanoparticle size to date.…”