Biomass carbon quantum dots: mimicking peroxidase-like activity and sensitive fluorometric and colorimetric detection of dopamine hydrochloride in meat products

Abstract

Dopamine (DH), as a kind of "lean meat powder", is easily accumulated in animal tissues and further endangers the health of consumers. As a result, developing a quick, sensitive, and cost-effective approach for detecting DH concentration is critical to food safety. In this paper, fluorescent carbon quantum dot (CQDs) peroxidase mimetic enzymes with remarkable stability and high catalytic efficiency were produced utilizing a green synthesis technique from three types of food waste: corncob, sunflower seed husk, and grape seed. Then a colorimetric/fluorescent dual-mode sensor based on fluorescent CQDs was developed for the visual detection of dopamine hydrochloride in pork through changing the fluorescence brightness and color caused by its catalysis. The fluorescent CQDs generated from the three wastes were characterized, and the ones based on corncob performed the best as mimicked enzymes. Therefore, corncob fluorescent CQDs (CFCD) were used for the detection of DH. Under the optimal conditions, the linear range of DH measured by the fluorescent technique was 0.001∼0.6 mmol/L (R2=0.9947), with a detection limit of 7.86 nmol/L. The linear range of DH measured by the colorimetric technique was 0.001∼0.7 mmol/L (R2=0.9952), with a detection limit of 0.93 μmol/L. And with its high sensitivity and selectivity, it was successfully applied to the detection of DH in real samples. The developed CFCD concept may provide a novel method for the detection of DH. This comprehensive strategy promotes the high-efficiency conversion of biomass into CQDs and provides a theoretical basis for exploring the treatment of biomass waste.