Water-soluble InP/ZnS QDs as DBP markers. Alcohol influence on the solubility of phthalates
The interaction of semiconductor water-soluble InP/ZnS-PEG-COOH quantum dots (QDs) with dibutyl phthalate (DBP) in fresh and sea water samples was studied. It was found an increase of QDs luminescence (PL) depending on DBP concentration increase in a fresh water solutions. The QDs PL increase is caused by the localization of DBP molecules in the Onsager cavity of a quantum dot and the passivation of its surface. An increase in the ethanol concentration led to increase of the DBP solubility, what can serve as a means of the sensitivity enhancement when registering phthalates in aqueous media. Observations of the QDs luminescence dynamics in the seawater samples from the Black, Mediterranean, and White Seas have shown the individual character of the interaction of InP/ZnS QDs with DBP, including with an increase in the ethanol concentration. It has been established that plastic packaging containing even a small percentage of alcohol is potentially hazardous to human health.