INVESTIGATING THE DETERMINATION OF TYRAMINE IN CHEESE USING GOLD NANOPARTICLES (AUNPS) IN COMBINATION WITH NITROGEN-DOPED CARBON QUANTUM DOTS (N-CQDS) SYNTHESIZED BY MICROWAVE-ASSISTED METHOD

Abstract

Tyramine is a biogenic amine commonly found in products such as cheese, fish sauce, soy sauce, and kimchi
due to the decarboxylation of tyrosine during fermentation or decomposition. It is also one of the parameters
used to evaluate product quality. In this study, we developed a cost-effective and environmentally friendly
method to detect tyramine in food using fluorescence techniques with nitrogen-doped carbon quantum dots
(N-CQDs) combined with gold nanoparticles (AuNPs). N-CQDs were synthesized simply from citric acid
and urea within 5 minutes using a household microwave. These N-CQDs were then employed as reducing
agents to convert Au(III) salts into gold nanoparticles. The N-CQDs exhibited fluorescence quenching in the
presence of AuNPs and fluorescence recovery in tyramine. Under optimal conditions, the fluorescence
recovery of the N-CQDs/AuNPs system showed a linear relationship with tyramine concentration in the
range of 0.02 ppm to 1 ppm. The method demonstrated a relatively low limit of detection (LOD) at 6 ppb,
high recovery rates, and good repeatability (RSD < 5%). The method successfully detected tyramine in
cheese samples, yielding reliable results.