Mesoporous silica-based molecularly imprinted fluorescence sensor for the ultrafast and sensitive recognition of oxytetracycline

Molecularly imprinted sensor has been a common chemical sensor for the selective detection of target. Yet, the rapid detection of target was one of the remaining problems, which needs to be diligently improved. Herein, a molecularly imprinted mesoporous silicon material (N-CDs@mMIPs) was successfully prepared for the rapid, sensitive and selective detection of oxytetracycline (OTC). Non-toxic nitrogen-doped carbon quantum dots (N-CDs) with high fluorescence performance was chosen as a detectable fluorescence signal, OTC was the target analysis, 3-Aminopropyltriethoxysilane (APTES) as the functional monomer, tetraethyl silicate (TEOS) as the crossing link agent and cetyl trimethyl ammonium bromide (CTAB) as the pore-foaming agent. N-CDs@mMIPs was synthesized by the removal of CTAB and OTC. Under the optimal test conditions, the resultant N-CDs@mMIPs showed a faster response time within 0.5 min (30 s) and a lower detection limit of 0.035 μmol·L⁻¹ compared with molecularly imprinted sensor without mesoporous structure (N-CDs@MIPs) and other molecularly imprinted sensors. Consequently, N-CDs@mMIPs was applied for the detection of OTC in milk and honey, satisfied recovery rates of 99.80 %–100.60 % and 99.75 %–102.10 % were obtained respectively. In general, the pore structure in mesoporous silicon accelerated the mass transfer rate between target and fluorescent substance, which greatly shortened the detection time of N-CDs@mMIPs to OTC. Furthermore, the pore structure in mesoporous silicon could effectively avoid the self-aggregation of N-CDs, thus improved the sensitivity of N-CDs@mMIPs.