A multi-channel array for metal ions discrimination with animal bones derived biomass carbon dots as sensing units

This paper designed a multivariate analysis method through carbon dots (CDs) to detect and distinguish heavy metal ions in aqueous systems. The carbon dots were derived from three kinds of animal bones through hydrothermal process. Therefore, N, O, S, Ca elements contained in the three different bones themselves are doped directly into the carbon dots by hydrothermal method. CDs gained from diverse raw materials (pork bone, bovine bone, and sheep bone) interact with heavy metal ions of varying degrees were used as probes to distinguish heavy metal ions Ag+, Cu2+, Hg2+, Fe3+ and Pb2+. Specific fingerprints are formed with the output signal, which is the changing rate of fluorescence intensity before and after the addition of metal ions to the bone CDs. The fingerprints indicate Fe3+ has the highest quenching effect on three biomass CDs, while Ag+ has the best quenching effect on sheep bone biomass CD and the detection range was 40–4000 nM. Hierarchical cluster analysis and linear discriminant analysis were used to distinguish Ag+, Cu2+, Hg2+, Fe3+ and Pb2+. The accuracy is 100% not only for individual ions, but also for binary and ternary mixtures. Simultaneously, metal ions in environmental water have been successfully distinguished. The sensor array can identify various metal ions in water simply, efficiently and systematically at the same time.