AbstractA 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 abstractSchematic 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 Eu3+but restored after the addition of PPi.

中文翻译：

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基于使用 Mn 掺杂的 ZnS 量子点并使用 Eu(III) 作为介体的开-关-开发光焦磷酸盐探针

摘要 设计了一种具有长衰减寿命的选择性磷光开关探针，用于检测焦磷酸离子（PPi）。检测方案基于使用铕 (III) 调制的 Mn (II) 掺杂的 ZnS 量子点，该量子点覆盖有 N-乙酰基-L-半胱氨酸。Eu(III) 离子引起的量子点聚集和电子转移都会导致磷光猝灭（“关闭”状态）。然而，磷光会在向系统中添加 PPi 后恢复（“开启”状态）。该效应归因于 PPi 和 Eu(III) 之间更强的相互作用，从量子点表面的羧基中去除了 Eu(III)。磷光强度（在 316/594 nm 激发/发射波长下测量最佳）和 PPi 浓度在 400 nM 至 6000 nM 之间存在线性关系，检测限为 145 nM。量子点的长寿命磷光 (1920 μs) 提供了另一个吸引人的特征。它可用于通过执行时间分辨测量来消除生物样品中短寿命荧光的干扰。该探针用于测定尿液样品中加标的 PPi，回收率范围为 98% 至 105%，RSD 小于 2.0%。用于灵敏和选择性检测焦磷酸根离子 (PPi) 的长寿命磷光开关探针示意图。它基于使用 Eu(III) 调制的 Mn(II) 掺杂 ZnS 量子点 (QD)。