依据氧气对物质荧光的猝灭作用,研究了一种基于时域荧光寿命的水体溶解氧浓度检测方法,根据荧光猝灭曲线上的两点计算荧光寿命,并通过Stern-Volmer方程反演获得水体溶解氧浓度。结果表明:相同溶解氧浓度下,归一化处理后的荧光猝灭曲线不受激发光强度和激励持续时间等激发条件的影响;不同溶解氧浓度下,实测荧光寿命受系统延迟的影响,补偿后荧光寿命理论曲线与修正曲线具有良好的一致性,拟合相关系数达0.9985。与HQ30d溶解氧分析仪对比,测试结果表明,0~20 mg·L ^-1范围内溶解氧质量浓度测量误差小于0.5 mg·L ^-1,线性相关系数达0.9992。

On the basis of the quenching effect of oxygen on the material fluorescence, we developed an analytical method based on time-domain fluorescence lifetime to detect the concentration of dissolved oxygen in water. The fluorescence lifetime is calculated according to two points on the fluorescence quenching curve, and the dissolved oxygen concentration in water is then obtained by the inversion of Stern-Volmer equation. The results showed that under the same dissolved oxygen concentration, the normalized fluorescence quenching curve is not affected by the excitation conditions, such as the intensity of the excitation light and the duration of excitation. The measured fluorescence lifetime of different dissolved oxygen concentrations is affected by the system delay. The theoretical curve of the fluorescence lifetime after compensation is in good agreement with the modified curve with the fitting correlation coefficient of 0.9985. Compared with the HQ30d dissolved oxygen analyzer, the measurement error of the dissolved oxygen in the mass concentration range of 0-20 mg·L -1 is less than 0.5 mg·L -1 while the fitting correlation coefficient reach to 0.9992. These results showed that it could be an effective method for the measurement of dissolved oxygen concentration in water.