The room-temperature phosphorescence (RTP) of Mn-doped ZnS quantum dots (Mn–ZnS QDs) was quenched by the addition of selenite in the presence of glutathione. The quenching of the RTP emission of Mn–ZnS QDs was due to HSe− ions which was the reaction product of selenite and glutathione. Based on the above finding, a simple, rapid, sensitive probe for selective detection of selenite was successfully fabricated. Under the optimal experimental conditions, a linear relationship was obtained covering the linear range of 0.1–5.0 μmol L−1 and the detection limit (3σ) was 0.085 μmol L−1. The proposed method was successfully applied for the determination of selenite in sodium selenite tablets and sodium selenite and vitamin E injection with satisfactory results.
