Portable ratiometric probe based on the use of europium(III) coordination polymers doped with carbon dots for visual fluorometric determination of oxytetracycline.

Abstract

A novel ratiometric fluorescent probe for the determination of oxytetracycline (OTC) was developed. The method is based on the use ofadenosine monophosphate/Eu(III) nanoscale coordination polymersdoped withcarbon dots (CDs) (CD@AMP/Eu NCPs). These were fabricated by self-assembly of Eu3+ and AMP on the surface of CDs containing large amounts of hydroxyl and carbonyl groups. Under the excitation at 310nm wavelength, the dopedNCPs display strong pinkemission of Eu3+ at 615nm and blue emission of theCDs at 430nm on exposure to OTC. The ratio offluorescence intensity (F615/F430) of such NCPs displays excellent linear relationship with OTC concentration ranging from 0.2 to 60μM and the limit of detection (LOD) is 25nM (3σ). The doped NCPs were evenly immobilized on common filter paper to prepare avisual ratiometric probe for the determination of OTC. Assisted by a digital camera with an APP color detector, the paper-based test strip was applied for the quantitative determination of OTC with a LOD of 0.5μM and a wide linear scope of 1-100μM. The method was applied to the determination of OTC in milk samples. Graphical abstractSchematic representation of the principle for oxytetracycline (OTC) determination using carbon dots (CD)@adenosine monophosphate (AMP)/Europium (Eu3+) paper-based ratiometic probe.