Discrimination and detection of benzaldehyde derivatives using sensor array based on fluorescent carbon nanodots

Excessive residual benzaldehyde derivatives in environment can cause severe ecological problems. There are currently less simple, rapid, sensitive and low-cost methods available to detect benzaldehyde derivatives. In this study, fluorescent nano-probes based on carbon nanodots (CDs) were developed for the determination of benzaldehyde derivatives in aqueous solution. Three kinds of classical CDs with different structure and photoluminescence characteristic were randomly chosen and prepared by using different carbon source and synthetic methods Static fluorescent quenching occurred to CDs in the presence of benzaldehyde derivatives. The concentration detection range covered from μM level to mM level, and the minimum detection limit reached 0.3 μM. Benzaldehyde derivatives with various structures and functional groups contributed differential fluorescent quenching degrees to CDs through the donor-acceptor electronic effect. On this basis, sensor array based on CDs was constructed for the discrimination and determination of benzaldehyde derivatives. Two principal components contributing 99.22% of the total variability were extracted by using principal component analysis method (PCA). PCA scattergraph was plotted and applied to descriminate five benzaldehyde derivatives intuitively, including 2,4-dihydroxybenzaldehyde, salicylaldehyde, m-hydroxybenzaldehyde, benzaldehyde and m-methylbenzaldehyde. Experimental results confirmed the practical utility and stability of the CD array for the assay of benzaldehyde derivatives.