| Chemiluminescence（CL） method is often used to determine some analytes directly or indirectly based on the CL intensities measured in chemiluminescence reactions. It shows excellent merits of high sensitivity, fast analysis, wide linear range, simple instruments and easy automation when coupled with flow-injection technique（FI） and therefore has been widely applied in the fields of biological, environmental and pharmaceutical analysis. However, the CL intensities of most common CL systems are relatively weak due to low quantum yield, which undoubtedly limited the analytical applications of such methods. In recent years, the prepartion and analytical applications of quantum dots（QDs） have attracted much attention due to their unique optical and electronic properties. Especially, several QDs-based CL methods show potentical applications in the field of analytical chemistry since some water-soluble QDs（such as CdTe, Cd S, Zn S, Zn Se, etc.） have been proved to have enhancement effect on the weak CL intensity of some CL systems.In this paper, it was found that both CdTe QDs and Zn Se QDs have obvious enhancement effect on the weak CL of the luminol-KIO4 system in alkaline media. Based on this, a series of flow-injection chemiluminescence method（FI-CL） have been developed for the determination of methionine, p-hydroxybenzonic acid and benzoic acid in commercial pharmaceutical formulations and water samples, respectively. The possible CL mechanism of the related systems has been discussed as well based on the possible production of O2?- and OH?. The present work helps to broaden the potential application of quantum dots-based chemiluminescence methods in pharmaceutical and environmental analysis.The main contents of the paper includes the following parts: 1 ReviewFirstly, the overview of definition, luminous principle, physical effects, optical properties and applications on quantum dots were introduced; Secondly, the concept, development history, characteristics, analytical applications of CL methods were summarized; The application of quantum dots-based luminol CL systems were especially reviewed, and the development of the luminol-based chemiluminescence system sensitized by quantum dots were tabulated. Totally 149 references were cited. 2 Determination of methionine by CdTe quantum dots enhanced luminol-potassium periodate chemiluminescence with a flow systemFI-CL method was established for the determination of methionine, based on its strong enhancement on CL intensity of the luminol-KIO4 system catalyzed by CdTe quantum dots in alkaline media. Under the optimized conditions, the relative CL intensity was in proportion to methionine concentration in the range from 1.0×10-8 to 1.0×10-5 g/m L with a detection limit of 6.6×10-9 g/m L（3σ）. The relative standard deviation（RSD） of the CL intensity for 1.0×10-6 g/m L standard methionine solution was 0.97 %（n=11）. The proposed method has been successfully applied to determine methionine in commercial pharmaceutical formulations and water samples with recoveries between 98.0 % and 102.4%. The production of O2?- and OH? was inferred by experiments and the possible CL mechanism was consequently proposed as well. 3 Determination of p-hydroxybenzonic acid by Zn Se quantum dots enhanced luminol-potassium periodate chemiluminescence with a flow systemFI-CL method has been established for the determination of p-hydroxybenzonic acid based on the significantly enhancement of p-hydroxybenzonic acid on the CL intensity of the luminol-KIO4 system sensitized by Zn Se quantum dots（QDs） in alkaline media.Under the optimized conditions,the relative CL intensity was in proportion to the p-hydroxybenzonic acid concentration in the range from 1.0×10-8 g/m L to 1.0×10-5 g/m L with a detection limit of 6.7×10-9g/m L（3σ）.The relative standard deviation（RSD） of the CL intensity for 1.0×10-6 g/m L p-hydroxybenzonic acid was 0.72 %（n=11）. The proposed method has been successfully applied to the determination of p-hydroxybenzonic acid in water samples with the recoveries between 97.8 % and 103.0 %. The possible mechanism of chemiluminecence was preliminary discussed as well. 4 Determination of benzoic acid by Zn Se quantum dots enhanced luminol-potassium periodate chemiluminescence with a flow systemFI-CL method has been established for the determination of benzoic acid based on the significantly inhibition of benzoic acid on the CL intensity of the luminol-KIO4 system sensitized by Zn Se quantum dots（QDs） in alkaline media.Under the optimized conditions,the relative CL intensity was in proportion to the benzoic acid concentration in the range from 1.0×10-7 g/m L to 1.0×10-5 g/m L with a detection limit of 5.7×10-8 g/m L（3σ）.The relative standard deviation（RSD） of the CL intensity for 1.0×10-6 g/m L benzoic acid was 1.02 %（n=11）. The proposed method has been successfully applied to the determination of benzoic acid in water samples with the recoveries between 92.7 % and 107.1 %. |
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