基于荧光猝灭原理的溶解氧分析仪的研制及其应用

Development and Application of Dissolved Oxygen Analyzer Based on Fluorescence Quenching Principle

研制出一种对溶解氧敏感的传感膜,其荧光材料主要是邻菲咯啉钌。由光源发出的中心波长为465 nm的强光照射到铺有该络合物的膜片上,激发出中心波长为620 nm的荧光,水体中的溶解氧会对激发出的荧光产生猝灭效应,猝灭程度与溶解氧的质量浓度之间存在线性关系。该膜片在无氧水中的荧光强度是空气饱和水中的20倍,变化较为明显。对比检测荧光信号在待测水体中猝灭前后的强度,即可测出水体中溶解氧的质量浓度。基于这一原理和荧光测量技术研制了光学溶解氧分析仪,利用该仪器对6处不同水域的天然水体进行测试,所得测试结果与国标碘量法的测试结果之间不存在显著性差异,误差≤2%,响应时间<1 min。在海水中30 m深处进行36h稳定性考察,所得溶解氧质量浓度数值平均偏差小于0.2 mg.L-1,证实仪器可适应较为恶劣的环境,且稳定性较好。

A sensor membrane sensitive to dissolved oxygen has been developed, and the main fluorescent material is an organic Ru complex. When excited by a strong light with a central wavelength of 465 nm, the sensor membrane can generate a fluorescence with a central wavelength of 620 nm, the dissolved oxygen in water can quench the excited fluorescence, and the quenching degree has a linear relationship with the dissolved oxygen concentration. The fluorescence strength of sensor membrane in the nitrogen-saturat- ed water is about 20 times that in the oxygen-saturated water, so making a comparison between the fluorescence signal strengths in a water sample before and after quenching will determine the dissolved oxygen concentration in the water sample. Based on the principle and the fluorimetric technology, an optical dissolved oxygen analyzer was developed and used to test 6 different natural water samples, and the results determined with the analyzer have no significant difference from those with the standard iodimetric method with an error of no greater than 2%and a response time of less than 1 minute. It is shown from the 36- hour -underwater stability test results that the mean deviation of the measued dissolved oxygen values is less than 0.2 mg/L, which indicates that the analyzer is applicable to adverse environment and has a better stability.