Multidimensional fluorescent array-sensing of biogenic amines based on porphyrin-functionalized carbon dots

Protein-rich foods release biogenic amines (BAs) during prolonged storage, and these compounds serve as key biomarkers of food spoilage. Current separation-based methods for detecting BAs in food require sophisticated instrumentation and laborious sample pretreatment procedures. The array-sensing strategy, which mimics biological olfaction, provides a simple and rapid approach for the simultaneous detection of multiple BAs without the need for separation. Here, we constructed a multidimensional fluorescent sensor array using porphyrin-functionalized carbon dots (P-CDs) and their composites with metal ions (M-P-CDs), thereby incorporating the excitation wavelength as an additional signal dimension. This design reduces the number of physical sensors required while maintaining high discrimination capability, thereby overcoming a key limitation of conventional sensor arrays that depend solely on increasing the number of sensors. With the support of chemometric and machine learning methods, the sensor array successfully discriminated among ten BAs. We achieved quantitative detection of putrescine, histamine, and tyramine, determining their limits of detection (LODs) to be 2.37, 2.96, and 1.55 mg/L, respectively. The sensor array exhibited excellent stability (i.e., no significant fluorescence change over 30 days) and high selectivity against common interfering substances. Validation experiments on milk samples demonstrated the array's ability to reliably discriminate specimens at different spoilage stages. This work establishes a novel multidimensional array-sensing strategy for detecting BAs, an approach that holds great potential for food safety applications.