เอกสารประชุมวิชาการระดับขาติมหาวิทยาลัยทักษิณ ครั้งที่ 28 2561

929 งานวิจัยและนวัตกรรมเพื่อสังคมที่มั่นคง มั่งคั่ง และยั่งยืน (Research and Innovation for Social Stability, Prosperity and Sustainability) Figure 7 The selectivity of TGA-capped CdTe QDs for the determination of Pb 2+ , the concentrations of Pb 2+ and other ions were 1.0 mg L -1 The influence of coexisting compounds on the fluorescence intensity of the TGA-capped QDs was also investigated and the results showed that other metal ions did not interfere in the determination of Pb 2+ with a relative error of < 5% (Table 1). These data demonstrated that the TGA-capped CdTe QDs can be used as a fluorescence probe for the selective determination of Pb 2+ and do not require the addition of any masking agents to eliminate interferences. Table 1 Interference studies of different metal ions on the fluorescence intensity of TGA-capped CdTe QDs. Conclusions An optosensor based on the quenching of the fluorescence of TGA–capped CdTe QDs was developed for the determination of Pb 2+ . The fluorescence response was linearly proportional to the concentration in the range of 0.05-50.0 mg L -1 with a coefficient of determination of 0.9981. The detection limit was 0.05 mg L -1 . The developed method detected the Pb 2+ and the advantages of this sensor are simplicity, rapidity, cost effectiveness, and high sensitivity with a low detection limit. Acknowledgements Naphat Yuphintharakun was supported by the faculty of Science Research Fund, Prince of Songkla University, Hat Yai, Thailand, Contract no. 1-2559-02-009. Coexisting substances Tolerance ratios %Relative error Na  (Cl  ) 100  1.8 Na  (SO 4 2  ) 100  4.1 Mg 2  (Cl  ) 100  3.1 Mg 2  (SO 4 2  ) 100  1.1 K  (Cl  ) 100  2.4 K  (Br  ) 100  3.5 K  (SO 4 2  ) 100  1.7 Zn 2  (Cl  ) 50  2.4 Zn 2  (SO 4 2  ) 50  3.4 Ni 2  (Cl  ) 50  4.6 Ni 2  (NO 3  ) 50  1.8 Fe 2  (Cl  ) 50  3.9