Development of a sensitive B12 determination method based on inner filter effect on CdTe quantum dots

In this study, we developed a selective and sensitive inner filter effect-based method by thioglycolic acid capping CdTe quantum dots (TGA-CdTe QDs) for the quantitative determination of Vitamin B12 (B12). The effect of all experimental parameters and possible interference agents for determination of B12 by TGA-CdTe, were individually investigated and optimized. In addition, the mechanism of this detection method was discussed in detailed. Under the optimum conditions, the fluorescence-quenching rate of the TGA-CdTe QDs showed a relative linear relationship against B12 concentration in the ranges of 0.02–0.4 and 1.5–70.0 μM B12 with a detection limit of 2.0×10-8 M. Furthermore, the accuracy, precision and the practical application of determination of B12 by this developed method, were studied in pharmaceutical formulations injection without any sample pretreatment process. The percentage recoveries for B12 determination in these real samples were obtained in the range of 95.0%–105.0%.