基于平面光极的DO二维实时监测系统在生物扰动存在下水/沉积物体系中的应用

采用改进的平面传感膜制备方法,建立应用于淡水/沉积物模拟体系的溶解氧(DO)二维分布监测系统.结果表明:采用物理包埋法将荧光指示剂三(4,7-联苯-1,10-邻菲啰啉)二氯化钌固定于乙基纤维素膜上,制备的DO平面传感膜荧光强度随DO质量浓度的增加而减小,符合荧光淬灭的Stern-Volmer方程,具有DO响应范围宽(0~20mg/L)、响应速度快(60s)、准确性高、可逆性和稳定性好等优点;在生物扰动存在下,沉积物DO变化较小,对上覆水DO影响较大,这是由于物理混合和氧化还原等多种机制综合作用所致,生物扰动将直接或间接影响这些作用.

Application of a Real Time Two Dimensional DOMonitoring System Based on Planar Optode ina Water/Sediment System under Bioturbation

A new plane sensing membrane was developed in the study, and then a system was established to monitor the spatial and temporal distribution of dissolved oxygen (DO) in a simulated freshwater/sediment microcosm. Sensing foils were fabricated by physical entrapping fluorescent indicator tris(4,7
-diphenyl-1,10-phenanthroline)ruthenium dichloride in ethyl cellulose film, and the emission fluorescence intensity was decreased with the increase of the concentration of dissolved oxygen, which conforms to the Stern Volmer equation of the fluorescence quenching mechanism. The sensor is precise, stable, with fast response time (<60 s) and good reversibility, and has a wide DO sensitive range (0—20 mg/L). According to the monitoring results by the system, although the temporal and spatial variation in the sediment was minor under bioturbation, the sediment has significant effects on the DO of overlying water. Complex changes of DO in the system were the result of combined effects of a variety of mechanisms such as physical mixing and redox. And these effects were all affected by bioturbation.