碲化镉量子点荧光猝灭法测定镍

基于镍离子对碲化镉(CdTe)量子点荧光具有猝灭作用,建立了对镍离子的定量检测方法。实验表明,在5 mL比色管中依次加入0.5 mL 1.5×10^-4 mol/L CdTe量子点溶液(以Cd²⁺计)、50 μL不同镍离子浓度的标准溶液,用pH 10.0硼砂缓冲溶液定容,室温下反应10 min,以400 nm为激发波长,在荧光发射波长为608 nm处测定其相对荧光强度,CdTe量子点荧光衰减程度与镍离子浓度在2.0×10^-7～7.8×10^-5 mol/L范围内呈线性关系,其线性回归方程为F₀/F=1.008 9+0.030 8 ρ(μmol/L),相关系数r=0.998 7,检出限为1.5×10^-7 mol/L。方法用于水样中镍离子的测定,测得结果与原子吸收光谱法(AAS)一致,相对标准偏差(RSD,n=5)为5.6%。

Determination of nickel by cadmium telluride quantum dots fluorescence quenching method

A quantitative method for determination of nickel was established based on the fluorescence quenching effect of nickel ion on cadmium telluride(CdTe) quantum dots. The experimental results indicated that the fluorescence attenuation degree of CdTe quantum dots was linear to the concentration of nickel ions in range of 2.0×10^-7-7.8×10^-5 mol/L under the following conditions: 0.5 mL of 1.5×10^-4 mol/L CdTe quantum dots solution (in Cd²⁺) and 50 μL nickel standard solution with different concentrations were added into 5 mL colorimetric tube successively; the mixed solution was diluted to the mark with borax buffer solution at pH 10.0; after reaction at room temperature for 10 min, the relative fluorescence intensity was determined at fluorescence emission wavelength of 608 nm with 400 nm as excitation wavelength. The equation of linear regression was F₀/F=1.008 9+0.030 8 ρ (μmol/L) with correlation coefficient of r=0.998 7. The detection limit was 1.5×10^-7 mol/L. The proposed method was applied to the determination of nickel ions in water sample. The results were consistent with those obtained by atomic absorption spectrometry (AAS). The relative standard deviation (RSD, n=5) was 5.6%.