A ratiometric fluorometric probe for doxycycline in food by using bovine serum albumin protected Au nanoclusters

Doxycycline (DOX) is widely used as feed additive and may remain in animal food. Thus, the detection of DOX in food field has become important. This work has reported a simple and rapid strategy to detect DOX by ratiometric fluorescence method without any sensitization materials based on bovine serum albumin (BSA) protected Au nanoclusters (BSA-Au NCs). Under excitation at 390 nm, the BSA-Au NCs has displayed two distinct emission peaks at 510 nm and 640 nm which are respectively originated from BSA and Au NCs, respectively. The fluorescence intensity ratio of I510/I640 of BSA-Au NCs probe has presented a good linear range (0.1–30 μM) and 0.006 μM limit of detection for DOX. This method was used successfully to detect DOX in food samples and the good recoveries reached 96.7–103.7%. The research has showed that potential application of BSA-Au NCs in food field because of its convenient synthesis scheme and excellent selectivity and sensitivity.