title: Determination of arsenic based on quenching of CdS quantum dots fluorescence using the gas-diffusion flow injection method.
abstract: A sequential injection analysis system for determination of arsenic based on hydride generation and fluorescence quenching of mercaptoacetic acid capped cadmium sulfide quantum dots (CdS-MAA QDs) is described. The generated arsine diffused across the PTFE membrane in a gas-diffusion unit and subsequently interacted with CdS-MAA QDs. The parameters affecting the arsine generation and the fluorescence quenching of QDs were studied. Under the optimum conditions, it was observed that a increase in the concentration of As(III) corresponded well to a decrease in fluorescence intensity according to the Stern-Volmer relationship. The extent of quenching was dependent on the concentration of arsenic in the range of 0.08-3.20 mmol L(-1), with the detection limit of 0.07 mg L(-1). The precision (%RSD) from eight replicates of the determination of As(III) 1.0 mg L(-1) was found to be 1.4%. The proposed method was applied to the determination of arsenic in ground water samples with satisfactory recoveries.
authors: Department of Chemistry and Center for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand.
authors: Nutthaya
authors: N
authors: Butwong
authors: Tuanjai
authors: T
authors: Noipa
authors: Rodjana
authors: R
authors: Burakham
authors: Supalax
authors: S
authors: Srijaranai
authors: Wittaya
authors: W
authors: Ngeontae