超低浊度测定方法的研究

Research on Ultra-low Turbidity Measurement Method

饮用水水质检测有利于提高水质管理效率。作为水质重要指标,浊度的准确测定至关重要。根据标准HJ 1075-2019《水质浊度的测定浊度计法》,采用入射光为860nm±30nm光源,将检测器放置与入射光呈90°的位置上测定待测样品的浊度,该方法的检出限只能达到0.3NTU,无法满足饮用水检测需求。为准确测定更低浓度的浊度,基于HJ 1075-2019和ISO 7027标准中浊度测量原理,本文研究出新型的浊度在线检测装置,创新型的设计光源调节系统,并将多个检测器固定在与入射光呈90°的平面上,形成一个检测圈,提高了信噪比,降低了测量检出限,将浊度的测定下限降低到0.02NTU,且具有较好的准确度与稳定性。该低量程浊度检测仪可较好的适用于饮用水中浊度测定,有利于推进饮用水浊度在线监测领域国产化设备的进程。值得一提的是,该装置为光学法检测设备信噪比提高和在线检测设备开发提供了参考价值。

Drinking water quality detection is beneficial to improve the efficiency of water quality management.As a typical index of water quality,the accurate determination of turbidity plays an important role in water quality monitoring.According to the standard of“HJ 1075-2019 Water quality-Determination of turbidity–Nephelometry”,a light source with incident light of 860nm±30nm is used,and the detector is placed at a position of 90°from the incident light to determine the turbidity of the sample.The detection limit of this method can only reach 0.3 NTU,which cannot meet the requirements of drinking water detection.In order to accurately measure the turbidity of lower concentrations,a new online turbidity detection device has been developed based on the turbidity measurement principle in HJ 1075-2019 and ISO 7027 standards.This device uses an innovative light source adjustment system,and multiple detectors are fixed on a plane at 90°from the incident light to form a detection circle,which greatly improves the signalto-noise ratio.The detection limit of turbidity is reduced to 0.02NTU with good accuracy and stability.This low-range turbidity detector can be well applied to the determination of turbidity in drinking water,and is conducive to promoting the process of domestic equipment in the field of online monitoring of drinking water turbidity.It is worth mentioning that the device provides a reference value for improving the signalto-noise ratio of optical detection equipment and developing on-line detection equipment.