基于荧光法的明场海水叶绿素传感器设计

Design of Brightfield Seawater Chlorophyll Sensor Based on Fluorescence Method

叶绿素是海洋生态环境监测的重要指标,是预测"赤潮"、"绿潮"的最直接参数。针对海水叶绿素信号微弱,且易受环境光干扰的难题,本文基于互相关原理设计的正交数字锁相放大器,实现了对叶绿素微弱荧光信号提取和环境光屏蔽。通过该方法设计的叶绿素原位传感器,检出限0.023μg/L,精密度1%,最大测量误差在2μg/L以内,传感器在动态范围内(0~200μg/L)线性度为0.999 6,与日本亚力克AAQ171型叶绿素传感器的长期现场对比,优于AAQ171型叶绿素传感器且具有较高的可靠性、灵敏度及分辨率等性能,可广泛应用于海洋浮标、台站等生态监测平台。

The Chlorophyll is an important indicator of marine ecological environment monitoring and the most direct parameter to predicting"red tide"and"green tide". Aiming at the problem that the seawater chlorophyll signal is weak and susceptible to ambient light interference, a digital lock-in amplifier designed using the cross-correlation principle can realize the extraction of the weak chlorophyll fluorescence signal and the shielding of ambient light. The chlorophyll in-situ sensor designed by this method has a detection limit of 0.023 μg/L,a precision of 1%,a maximum measurement error within 2 μg/L,and a linearity of 0.999 6 within the dynamic range(0~200 μg/L)of the sensor. The long-term field comparison of the Aggreko AAQ171 chlorophyll sensor is better than the AAQ171 chlorophyll sensor and has higher reliability, sensitivity and resolution. It can be widely used in marine buoys, stations and other ecological monitoring platforms.