AbstractA nanoprobe is described for the ratiometric fluorometric determination of sulfite ions. Upconversion nanoparticles (UCNPs) of the type β-NaYF4:Yb(III),Er(III),Tm(III) were covalently modified with the molecular probe HIAN which is a hydroxynaphthalimide fluorophore modified with a (cationic) indolinium moiety. Under excitation at 980 nm, the green emission of the UCNPs (peaking at 543 nm) is almost totally quenched, while the NIR emission (peaking at 802 nm) remains unaffected. In the presence of sulfite or bisulfite (hydrogen sulfite), the green fluorescence is restored and can be visually observed. A ratiometric method was worked out by measurement of the ratio of the green and NIR emissions. The analytical range extends from 10 to 250 μM, the limit of detection is 0.14 μM, and the assay can be performed within 40 s. Graphical abstractBased on the use of a molecular probe for sulfite and hydrogen sulfite, and by exploiting an inner filter effect (IFE), an assay for sulfite/hydrogen sulfite was developed by using upconversion nanoparticles (UCNPs). Addition reaction of sulfite/bisulfite with the material results in weakened IFE and enhanced green fluorescence of the UCNPs at excitation/emission wavelengths of 980/543 nm.

中文翻译：

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用于亚硫酸盐和亚硫酸氢盐荧光开启检测的比率上转换纳米探针

摘要描述了一种用于亚硫酸根离子比率荧光测定的纳米探针。β-NaYF4:Yb(III)、Er(III)、Tm(III) 类型的上转换纳米粒子 (UCNP) 用分子探针 HIAN 共价修饰，HIAN 是一种用（阳离子）二氢吲哚部分修饰的羟基萘酰亚胺荧光团。在 980 nm 激发下，UCNPs 的绿色发射（在 543 nm 处达到峰值）几乎完全被淬灭，而 NIR 发射（在 802 nm 处达到峰值）保持不受影响。在亚硫酸盐或亚硫酸氢盐（亚硫酸氢盐）存在下，绿色荧光恢复，可目视观察。通过测量绿色和 NIR 发射的比率制定了比率法。分析范围从 10 到 250 μM，检测限为 0.14 μM，可在 40 s 内进行测定。图形摘要基于对亚硫酸盐和亚硫酸氢盐的分子探针的使用，并通过利用内部过滤效应 (IFE)，使用上转换纳米粒子 (UCNPs) 开发了亚硫酸盐/亚硫酸氢盐的测定方法。亚硫酸盐/亚硫酸氢盐与材料的加成反应导致 UCNP 在 980/543 nm 激发/发射波长下的 IFE 减弱和绿色荧光增强。