A carbon quantum dot@mesoporous silicon composite-based fluorescent probe for chlortetracycline hydrochloride and gentamicin†

Abstract

Antibiotics, such as chlortetracycline hydrochloride (CTC) and gentamicin (GTM), pose a significant threat to human health and ecosystems. Therefore, stable analytical tools to identify CTC and GTM are of great practical importance. For accuracy and sensitivity, mesoporous SBA-15 silica was chosen as the solid support material to enhance the photostability of the detection system. Carbon quantum dots (CDs) as fluorescence signal emitters were introduced into SBA-15, and a fluorescent nanoprobe, CDs@SBA-15, exhibiting remarkable selectivity and sensitivity was constructed. The composite-based nanoprobe showed remarkable selectivity toward GTM, enabling the sensitive detection of GTM. The fluorescence spectrum of CDs@SBA-15 was altered in a “turn-on” manner when GTM was present, and the detection limit was 29 nM. Compared with the non-fluorescence response of CDs toward GTM, the superior fluorescence response of CDs@SBA-15 toward GTM was due to the immobilization of the CDs and the spatially restricted domain effect of the pore channels of SBA-15. In addition, the nanoprobe showed excellent selectivity for CTC in a “turn-off” manner and could sensitively detect CTC in the ranges of 0–4.0 and 4.0–100.0 μM with a detection limit of 113 nM. Moreover, the feasibility of the fluorescent nanoprobe was verified using tap water samples.