Pre-concentration and determination of fluorescence quenching of CdS quantum dots of Pb ions by dispersive liquid–liquid microextraction in the presence of the ionic liquids
Abstract
Purpose
This study aims to develop a new simple and sensitive method for the microextraction of trace levels of lead in environmental samples. It is based on the use of ionic liquids based dispersive liquid–liquid microextraction (IL–DLLME) before spectrofluorometry.
Design/methodology/approach
Cadmium sulphide quantum dots have been synthesised using thioglycolic acid as capping agent through a one-step process with stability and excellent water-solubility, and have strong affinity for lead (Pb). This probe is based on the fluorescence quenching effect of functionalised cadmium sulphide quantum dots.
Findings
Factors affecting the extraction efficiency and fluorescence quenching of metals, such as the amount of ionic liquid, amount of metanol, microextraction and centrifugation time, volume of quantum dots and buffer pH, were investigated. Under optimum conditions, the calibration graph was linear in the range of 0.01-3 µg.L-1, with the detection limit of 0.004 µg.L-1 for Pb2+. The relative standard deviation (RSD%, n = 5) of 5.4 per cent at 1 µg.L-1 of Pb2+ was obtained.
Originality/value
This method for pre-concentration of the Pb ions by dispersive liquid–liquid microextraction is novel and could be used for various applications in the synthesis of a wide variety of determination of fluorescence quenching of cadmium sulphide quantum dots.
Keywords
Citation
Jafarnejad, E., Abolhasani, J. and Derakhshan, A. (2018), "Pre-concentration and determination of fluorescence quenching of CdS quantum dots of Pb ions by dispersive liquid–liquid microextraction in the presence of the ionic liquids", Pigment & Resin Technology, Vol. 47 No. 2, pp. 127-132. https://doi.org/10.1108/PRT-11-2015-0115
Publisher
:Emerald Publishing Limited
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