Automatic in situ sensor based on K2S2O8 oxidation method for total phosphorus detection in marine water

作者：Yanmin Zhang, Shougang Chen, Yan Liu, Yan Zou, Yang Wang, Shuwei Zhang, Xiangfeng Kong, Yang Gao, Nan Gao · 发表于：Frontiers in Marine Science · 年份：2024 · DOI：10.3389/fmars.2024.1492115 · 被引用次数：6 · 研究领域：Water Quality Monitoring and Analysis、Analytical Chemistry and Sensors、Electrochemical sensors and biosensors

Phosphorus is a key indicator for water quality management due to its role in eutrophication. The variety of phosphorus-containing substances necessitates highly sensitive detection of total phosphorus, particularly through automated methods, to ensure water safety. This study involved the independent development of a sensor featuring an automated in situ detection technique. Utilizing potassium persulfate high-temperature oxidation and phosphorus molybdenum blue spectrophotometry, total phosphorus was monitored in situ via sequential injection technology. Additionally, the detection process and reaction conditions of the sensor were optimized, and a temperature compensation algorithm and turbidity correction were applied to mitigate environmental factors. Under optimal conditions, the sensor demonstrated a detection limit of 1.9 µg/L with a range of 6.5–1000 µg/L in seawater, and 1.2 µg/L with a range of 4.1–2000 µg/L in freshwater. The digestion efficiency for five representative phosphorus-containing substances was found to range from 87.3% ± 1.7% to 103.1% ± 0.6%. Notably, the sensor was deployed for in situ operation at a marine experimental station and online at a river monitoring station. With its integration, low power consumption, and high precision, the sensor enabled long-term unattended monitoring, delivering accurate, stable, and reliable results.