Silva, Ana SanchesVilarinho, FernandaBuonocore, Giovanna2017-02-212017-02-212016-06http://hdl.handle.net/10400.18/4332Engineered nanomaterials (ENMs) are increasingly being used due to their physical and chemical properties that allow improving a wide range of consumer products. Although they present a vast number of benefits, they also present risks to human health and the environment. Therefore, there is the need of evaluating the risks of nanotechnologies in foods. To fulfill this require new techniques are being developed. Fluorescent labeling is a simple approach for particle tracking that presents low detection limits. A fluorescent organic dye can be directly incorporated into layered silicates like montmorillonite (MMT) by ionic exchange but this can be dislodged from the substrate during the extrusion process. However the covalent bond of the fluorescent tag to the nanoclay can be a good alternative because it provides stability between the fluorescent tag and the clay. The main objective of this study was to develop an analytical method by Ultra High Performance Liquid Chromatographic (UHPLC) to determine fluorescein 5-maleimide, a fluorescent compound, as potential label of MMT. Conditions like chromatographic column, column temperature, mobile phase composition, mobile phase gradient as well as detector conditions were tested. Fluorescence detector and diode array detector (DAD) were compared. In general good linearity was found, excellent determination coefficients were achieved in all cases. Regarding the response of both detectors, as expected, better response was also obtained with fluorescence detector, allowing obtaining lower limits of quantification. The quantification limits of fluorescein 5-maleimide with the fluorescence detector were, at least, 10 times lower than with the DAD detector. Different behaviour was found in the two solvents tested. Ethanolic solutions allowed obtaining lower detection limits (LOD) than methanolic solutions (LOD ethanol = 0.03 µg/mL; LOD methanol =0.06 µg/mL, using fluorescence detector).engSegurança AlimentarFluorescent LabelingFluorescein 5-maleimideMontmorilloniteNanoclayconference object