Development of a thiol-capped core/shell quantum dot sensor for acetaminophen

Acetaminophen (AC) is a frequently used pharmaceutical which has been detected in water systems and is of concern due to its potential environmental impacts. In this study, three quantum dot (QD)-ligand systems, namely L-cysteine (L-cys)-, N-acetyl- L-cysteine (NAC)- and glutathione (GSH)-capped CdSe/ZnS quantum dots, were synthesized and tested for the fluorescence detection of acetaminophen. Among the synthesized aqueous core/shell quantum dots, L-cys-CdSe/ZnS QDs were found to be optimal with high sensitivity for the fluorescence detection of acetaminophen. The L-cys-CdSe/ZnS QDs were of a zinc blende crystal structure and displayed excellent fluorescence intensity and photostability and provided a photoluminescence quantum yield of 77 % . The fluorescence of L-cys-CdSe/ZnS QDs was enhanced by the introduction of AC enabling the development of a fast and simple method for the detection of AC. Under optimal conditions, F-F0 was linearly proportional to the concentration of AC from 3.0–100 nmol L–1 with limits of detection and quantification of 1.6 and 5.3 nmol L–1, respectively. Some related pharmaceutical compounds including epinephrine hydrochloride (EP), L-ascorbic acid (AA), uric acid (UA), dopamine hydrochloride (DA) and 4-aminophenol (4-AP) did not interfere with the sensing ofAC. The probe was also successfully applied in the determination of AC in tap and river water matrices.The University of Pretoria, the Water Research Commission (Grant K5/2438/1 and K5/2752) as well as the Photonics Initiative of South Africa (Grant PISA-15-DIR-06).http://www.journals.co.za/sajchemam2019Chemistr