一种近红外Cd²⁺荧光探针在电子烟雾化物中的应用

Application of a Near-Infrared Cd²⁺ Fluorescent Probe in Electronic Cigarette Aerosols

摘要: 镉离子(Cd²⁺)作为与肾功能损伤和骨骼疾病相关的致癌性重金属，通过电子烟加热线圈降解和调味烟液杂质逐渐污染电子烟气溶胶。现有检测方法(如电感耦合等离子体质谱法ICP-MS和原子吸收光谱法AAS)因缺乏现场分析便携性且在复杂气溶胶基质中分辨率不足而受限。为此，我们开发了一种新型开启式荧光探针(CdP)，专为复杂气溶胶基质中镉离子的高灵敏度检测设计，并验证了其在电子烟气溶胶分析中的应用。该探针通过四步法合成：2-羟基-1,4-萘醌与2-羟基-4-硝基苯胺缩合(产率74.6%)、锌还原(产率87.7%)、甲酰化(产率79.3%)和最终腙取代(产率86.6%)，巧妙利用苯吩恶嗪的结构刚性，通过配位作用实现镉离子的选择性识别。结合Cd²⁺后，探针因抑制腙吡啶基团的光诱导电子转移(PET)效应，在吸收光谱中呈现57 nm红移(463 → 520 nm)，并在610 nm处荧光强度增强225倍。定量分析显示荧光强度与0.1~0.6当量Cd²⁺浓度呈现线性关系(R² = 0.9974)，检测限在超纯水中为1.54 nM，在电子烟气溶胶提取物中为2.11 nM。该探针对18种共存离子(如10倍浓度Zn²⁺、Cu²⁺)干扰极小，并通过标准加入法验证在气溶胶基质中回收率 > 97.8%。相较于需仪器的传统探针，CdP通过比色变化(黄色→红色)实现裸眼检测，同时克服现有方法在低浓度气溶胶分析中的局限，为环境和消费品中镉离子的现场监测提供了实用工具。

Abstract: Cadmium ions (Cd²⁺), a carcinogenic heavy metal linked to renal dysfunction and bone disorders, increasingly contaminate e-cigarette aerosols through coil degradation and flavored e-liquid impurities. Current detection methods—such as ICP-MS and AAS—lack portability for on-site analysis and exhibit poor resolution in complex aerosol matrices. To bridge this gap, we developed a novel turn-on fluorescent probe (CdP) specifically engineered for high-sensitivity cadmium ion detection in complex aerosol matrices, with demonstrated applicability in electronic cigarette emission analysis. Synthesized via a four-step protocol involving condensation of 2-hydroxy-1,4-naphthoquinone with 2-hydroxy-4-nitroaniline (74.6% yield), zinc reduction (87.7% yield), formylation (79.3% yield), and final hydrazine substitution (86.6% yield), the probe leverages the structural rigidity of benzophenoxazine to achieve selective Cd²⁺ recognition through coordination interactions. Binding with Cd²⁺ induces a 57 nm bathochromic shift in absorption spectra (463 → 520 nm) and 225-fold fluorescence enhancement at 610 nm by suppressing photoinduced electron transfer (PET) from the hydrazinylpyridine moiety. Quantitative analysis demonstrated linearity (R² = 0.9974) between fluorescence intensity and Cd²⁺ concentration over 0.1~0.6 equivalents, with detection limits of 1.54 nM in ultrapure water and 2.11 nM in e-cigarette aerosol extracts. The probe exhibited minimal interference from 18 coexisting ions (e.g., 10-fold Zn²⁺, Cu²⁺) and maintained >97.8% recovery rates in aerosol matrices validated via standard addition methods. Unlike conventional probes requiring instrumentation, CdP enables naked-eye detection via colorimetric transition (yellow → red) while addressing limitations of existing methods in low-concentration aerosol analysis. This work provides a practical solution for on-site cadmium monitoring in both environmental and consumer product contexts.