锌离子Zn2+对胆红素BR有着显著的荧光增强效应, 基于该荧光特性, 利用紫外可见光吸收和稳态荧光光谱技术提出了一种BR作为荧光探针用于Zn2+浓度检测的新方法, 特别是首次采用在波长663和600 nm处的稳态荧光强度比值方法系统地研究了其与锌离子浓度在0~90 μmol·L-1范围内变化的关系, 与常用的单波长荧光强度探测方法比较, 有效地避免了探针浓度变化及激发光强度变化等非目标因素的影响。 实验研究结果发现BR荧光探针对Zn2+的识别行为在0~20 μmol·L-1范围内, 探针BR 的荧光强度比值I663 nm/I600 nm与 Zn2+的浓度之间具备线性增长关系, 尤其是0~10 μmol·L-1有非常好的线性关系, 线性相关系数r=0.999 87, 同时Zn2+检测限为0.1 μmol·L-1 。 在20~90 μmol·L-1范围内, 荧光强度比值I663 nm/I600 nm趋于饱和。 研究发现对实时检测人体内的Zn2+具有很好的应用前景。

Based on the fluorescence enhancement effect of Zn2+ on bilirubin (BR), this work proposes a new method for the detection of Zn2+ concentration, and a systematically investigation of BR as a Zn2+ probe by using ultraviolet-visible light absorption and steady-state fluorescence spectroscopy has been conducted. Compared with the general single-wavelength fluorescence intensity method, this new detection method eliminates the impacts of the non-target effects of factors such as concentration variation of BR and the excitation light intensity, etc., and achieves a more accurate measurement capability in Zn2+ detection. Especially, for the first time we adopt the BR fluorescence intensities ratio at the emission wavelengths 663 and 600 nm, and investigate the dependence between this ratio and the Zn2+ concentration in the range from 0 to 90 μmol·L-1. The recognition behavior of BR probe to Zn2+ indicates that the BR fluorescence intensity ratio I663 nm/I600 nm increases linearly with the Zn2+ concentration in the range of 0~20 μmol·L-1. In particular, in the range 0~10 μmol·L-1 of Zn2+ concentration, the linear correlation coefficient r is 0.999 87, which demonstrates the linear dependence, and the detection limit is 0.1 μmol·L-1. In the Zn2+ concentration range from 20 to 90 μmol·L-1, the probe BR fluorescence intensity ratio is saturated. Accordingly, there is a positive prospect of BR fluorescence in the real-time human body Zn2+ detection.