Facile preparation of fluorescent N, S co-doped carbon dots for the sensitive detection of tetracycline and Al3+

Herein, intelligent N, S-doped fluorescent carbon dots (N, S-CDs) were constructed by using l -cysteine and carboxymethyl cellulose (CMC) polymer as precursors through a one-step hydrothermal method. The designed N, S-CDs displayed strong fluorescence (FL) emission with a FL quantum yield of 44.48 % and could be utilized for the quantitative tracing of TCs and Al 3+ via the “On-OFF-ON” FL transition with wide linear detection range (1.66–104.5 μM for TCH, 1.66–163.2 μM for OTC, 1.66–69.5 μM for DOX and 33–104.3 μM for Al 3+ ). The detection limits (LODs) of TCH, OTC, DOX and Al 3+ were calculated to be 53.02 nM, 95.61 nM, 41.87 nM and 57.69 nM, respectively. On the basis of the FL “On-OFF-ON” strategy, multiple logical gate operations including “NOR” and “INHIBIT”, were constructed successfully. Additionally, N, S-CDs uploaded to hydrogen bars were utilized for the recognition of TCs and Al 3+ in a portable manner, which revealed great application potential in the field of anti-counterfeiting and encryption.