A ratiometric carbon dots/AgInS2 quantum dots sensing probe for the kinetic determination of histamine resorting to N-PLS chemometric model

Biogenic amines are compounds that play several crucial roles in the human body but can also cause serious health problems when present at high concentrations in foodstuffs. Therefore, it is important to develop rapid, simple, cost-effective, and reliable analytical techniques for their monitoring, acting as indicators of food quality and preventing potential risks. In this sense, carbon dots and 3-mercaptopropionic acid (MPA)-capped AgInS2 (AIS) quantum dots were used as fluorescent probes to implement a ratiometric sensing platform, coupled to chemometrics, for the kinetic fluorometric determination of histamine in foodstuffs using second-order data. The obtained data were analysed through unfolded partial least squares (U-PLS) and N-way partial least squares (N-PLS). The model optimization revealed that the application of N-PLS yielded the best results and that a kinetic spectral acquisition for 5 min was enough to ensure reliable measurements. The developed method was evaluated using spiked samples of different complex matrices (tuna, tomato and hake fish), at different concentration levels, and the obtained results, in terms of figures of merit, confirmed its suitability, accuracy and effectiveness. In fact, a relative percentage error below 10%, with a coefficient of determination for the prediction higher than 0.9, was obtained, together with a LOD and LOQ of 1.26 and 3.80 mg L−1, respectively, which are much lower than the maximum threshold value established by European Union legislation for histamine in fishery products (200 mg kg−1). These results were obtained with samples containing uncalibrated species and without using toxic reagents, which attest the suitability of the procedure. Globally, the developed methodology proved to be accurate and much simpler and faster than the reference procedures. •A ratiometric sensing platform encompassing carbon dots and semiconductor Cd-free QDs was developed.•The spectral acquisition of 5 min was enough to selectively determine histamine in foodstuffs.•The N-PLS revealed better results in terms of figures of merits than U-PLS.•A relative percentage error below 10% with a R2P higher than 0.9 was obtained.•The obtained LOQ was below than the maximum threshold value established by the EU.