Department of Chemistry, Capital Normal University, Beijing, 100048, People's Republic of China.
Institute of Nuclear and New Energy Technology, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Beijing Key Lab of Radioactive Waste Treatment, Tsinghua University, Beijing, 100084, People's Republic of China.
Mikrochim Acta. 2018 Sep 26;185(10):480. doi: 10.1007/s00604-018-3003-3.
A selective phosphorescent on-off-on probe with long decay lifetime has been designed for the detection of pyrophosphate ions (PPi). The detection scheme is based on the use of europium(III)-modulated Mn(II)-doped ZnS quantum dots capped with N-acetyl-L-cysteine. Both the aggregation of quantum dots and electron transfer induced by Eu(III) ions cause phosphorescence to be quenched ("off" state). Phosphorescence is, however, restored on addition of PPi to the system ("on" state). The effect is attributed to the removal of Eu(III) from the carboxy groups on the surface of the quantum dots owing to the stronger interaction between PPi and Eu(III). A linear relationship exists between phosphorescence intensity (best measured at excitation/emission wavelengths of 316/594 nm) and PPi concentration in the 400 nM to 6000 nM with a detection limit of 145 nM. An additional attractive feature is provided by the long-lived phosphorescence (1920 μs) of the quantum dots. It can be used to eliminate interference by short-lived fluorescence in biological samples by performing time resolved measurements. The probe was applied to the determination of PPi in spiked in urine samples and gave recoveries in the range from 98 to 105% with RSDs of <2.0%. Graphical abstract Schematic of a long-lived phosphorescent on-off-on probe for the sensitive and selective detection of pyrophosphate ions (PPi). It is based on the use of Eu(III)-modulated Mn(II)-doped ZnS quantum dots (QDs). Phosphorescence is quenched of QDs after the addition of Eubut restored after the addition of PPi.
一种具有长衰减寿命的选择性磷光开-关-开探针已被设计用于检测焦磷酸根离子 (PPi)。检测方案基于使用铕(III)调制的 Mn(II)掺杂的 ZnS 量子点，其表面被 N-乙酰-L-半胱氨酸包裹。由于 Eu(III)离子引起的量子点聚集和电子转移，磷光被猝灭（“关”态）。然而，当向体系中加入 PPi 时，磷光会恢复（“开”态）。这种效应归因于由于 PPi 与 Eu(III) 之间的更强相互作用，从量子点表面的羧基基团中去除 Eu(III)。磷光强度与 PPi 浓度之间存在线性关系（在激发/发射波长为 316/594nm 时最佳测量），在 400nM 至 6000nM 范围内检测限为 145nM。量子点的长寿命磷光（1920μs）提供了一个额外的吸引人的特性。通过进行时间分辨测量，可以消除生物样品中短寿命荧光的干扰。该探针已用于测定尿液中加入的 PPi，回收率在 98%至 105%之间，相对标准偏差（RSD）<2.0%。
