Development of a Screening Method for Fluoroquinolones in Meat Samples Using Molecularly Imprinted Carbon Dots

Abstract

An accurate and simple screening method has been developed for the determination of fluoroquinolone antibiotics. Carbon dots were synthesized by simple hydrothermal treatment as highly fluorescent nano-sensors. They were subsequently used in the synthesis of organic-based molecularly imprinted polymers to develop fluorescence-based polymeric composites using enoxacin as a representative dummy template molecule of fluoroquinolones. The method was optimized concerning the pH of the medium and composite concentration. The normalized fluorescence intensity showed efficient quenching under optimized conditions upon successive addition of the template, with an excellent correlation coefficient. The proposed method was applied to eight other fluoroquinolones, exhibiting, in all cases, good correlation coefficients (0.65–0.992) within the same linearity range (0.03–2.60 mg mL−1). Excellent detection and quantification limits were been obtained for the target analytes down to 0.062 and 0.186 mg L−1, respectively. All studied analytes showed no interference with enrofloxacin, the most commonly used veterinary fluoroquinolone, with a percentage of cross-reactivity varying from 89.00 to 540.00%. This method was applied successfully for the determination of enrofloxacin in three different types of meat samples: beef, pork, and chicken, with good recoveries varying from 70 to 100% at three levels. This new procedure is an easy analytical method that can be useful as a screening method for monitoring the environmental hazard of fluoroquinolones in quality control laboratories.

Synthesis of Multicolor Carbon Dots Catalyzed by Inorganic Salts with Tunable Nonlinear Optical Properties

“…As the laser energy increased, the nonlinear absorption coefficient of sample A changed significantly from −183.98 cm GW −1 to −246.55 cm GW −1 , while the nonlinear optical responses of sample B and sample C were not improved evidently. In addition, the third-order nonlinear optical quality factor (FOM) was defined to evaluate the saturated absorption performance analysis of carbon dots, in which FOM = |Imχ (3) /α 0 |, where Imχ (3) is the imaginary part of third-order nonlinear polarizability and directly related to the nonlinear absorption coefficient β eff . According to the data in Table 3, the corresponding FOM values of sample A and sample B under laser excitation of the same energy (27.09 MW cm −2 ) were 2.84 × 10 −12 and 2.57 × 10 −12 esu cm, respectively.…”

“…Carbon dots, as an emerging photoluminescent material, have been extensively applied in bioimaging, biosensors, light-emitting diodes, and catalysis [ 1 , 2 , 3 , 4 , 5 ]. Compared with semiconductor quantum dots, carbon dots have superior properties such as environmentally benign chemical composition, tunable photoluminescence properties, diverse surface groups, and unique photoelectric and physicochemical properties, which bring a bright prospect [ 6 , 7 , 8 , 9 ].…”