ABSTRACT
Norfloxacin (NOX), a kind of quinolone antibiotic, is widely used in disease treatment and the control of human and livestock products. Due to overuse, norfloxacin has become a common organic pollutant in water. We combine the high specific surface area and high stability of metal-organic frameworks with the high selectivity of molecularly imprinted polymers. By grafting a carbon-carbon double bond on the surface of UiO-66-NH2, a molecularly imprinted layer is formed on the surface of UiO-66-NH2 upon free radical polymerization. The saturated adsorption capacity of UiO-66@MIP reaches 58.01 mg g-1. UiO-66@MIP exhibits high adsorption performance in real water samples and its recoveries range from 96.7% to 98.3%, which demonstrates a higher adsorption capacity and recovery than other molecularly imprinted materials and has potential applications in the removal of norfloxacin in real life.
ABSTRACT
The identification of synthetic antioxidants has considerable significance in food safety. Here, we described the development of a colorimetric sensor array for rapid detection of eight antioxidants in food through the redox reaction between CoOOH and antioxidants in the presence of colorimetric signal indicators. The CoOOH nanoflakes exhibited high catalytic oxidation activity and can independently catalyze oxidation signal indicators showing different colors. The color reaction was inhibited to different degrees in the presence of antioxidants, which resulted in distinct signal response patterns for their discrimination. The method showed good linearity in the range from 50 to 1000 nM for butylated hydroxytoluene (BHT), butylhydroxyanisole (BHA), propyl gallate (PG) and tert-butyl hydroquinone (TBHQ). Moreover, different proportions of antioxidants were located in the middle pattern of each single antioxidant, and showed certain linear relationships among different concentration ratios. Finally, the proposed colorimetric sensor array was used for practical applications where TBHQ and BHT were detected in biscuits and sausages, and BHA and PG were detected in fried pork kebabs, respectively. The results were further confirmed by high-performance liquid chromatography, which demonstrated the great potential of the colorimetry sensor array for practical applications.
