A Traveling Multi-Analyte Chemosensor Based on Wet-Chemical Colorimetry for Shipboard Seawater Analysis
Source abstract
Abstract
Continuous monitoring of seawater nutrients is crucial for marine resource research and conservation, yet it faces challenges due to the constraints of offshore working conditions. We developed a multi-analyte sensor based on flow analysis technology, which integrates wet-chemical colorimetry/fluorometry for the simultaneous in situ determination of nitrite, nitrate, ammonium, silicate, and phosphate in seawater. To mitigate bubble interference, an integrated gas-trapping cavity was designed, and a data-cleaning algorithm based on the interquartile range method was implemented. In June 2025, a sea trial was conducted at two stations in the northern South China Sea, the results of which showed high consistency with laboratory standard methods: the maximum absolute relative errors were 1.79% for nitrite, 5.01% for nitrate, 1.42% for ammonium, 5.93% for phosphate, and 2.95% for silicate. The performance under real marine conditions is demonstrated by relative errors below 6% and linear correlation coefficients exceeding 0.999 for all parameters. This research demonstrates a practical approach for in situ marine observation.
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Research context
OpenAlex topics: Marine and coastal ecosystems · Analytical Chemistry and Sensors · Water Quality Monitoring and Analysis
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
Affiliations
College of Ocean Science and Engineering, Shandong University of Science and Technology, Qingdao 266590, China
National Deep Sea Center, Qingdao 266237, China
Shandong Provincial Key Laboratory of Deep-Sea Biological Resources Exploration and Utilization, National Deep Sea Center, Qingdao 266237, China
School of Resources and Environment, Qingdao Agricultural University, Qingdao 266109, China
School of Ocean at Yantai University, Yantai University, Yantai 264003, China
Funding
National Key Research and Development Program of China · Key R&D Program of Shandong Province, China
References (33)
Show source-provided references
1. Riverine nutrient impact on global ocean nitrogen cycle feedbacks and marine primary production in an Earth system model10.5194/bg-21-4469-2024 ↗
2. Feedbacks between phytoplankton and nutrient cycles in a warming ocean10.1038/s41561-024-01454-w ↗
3. Influence of anthropogenic nutrient sources on kelp canopies during a marine heat wave10.1016/j.marpolbul.2025.117788 ↗
4. The interactive effects of temperature and nutrients on a spring phytoplankton community10.1002/lno.12023 ↗
5. Nutrient availability influences the thermal response of marine diatoms10.1002/lno.12671 ↗
6. Human-induced salinity changes impact marine organisms and ecosystems10.1111/gcb.16859 ↗
7. Exploring the type and strength of nonlinearity in water quality responses to nutrient loading reduction in shallow eutrophic water bodies: Insights from a large number of numerical simulations10.1016/j.jenvman.2022.115000 ↗
8. Li, C., and White, J.R. (2025). On the calculation of carbon and nutrient transport to the oceans. Sci. Rep., 15.10.1038/s41598-025-94058-2 ↗
9. Earth, Wind, Fire, and Pollution: Aerosol Nutrient Sources and Impacts on Ocean Biogeochemistry10.1146/annurev-marine-031921-013612 ↗
10. New Developments in the Marine Nitrogen Cycle10.1021/cr050377t ↗
11. Effect of different measurement methods on data quality of nutrients in seawater
12. Detection methods of ammonia nitrogen in water: A review10.1016/j.trac.2020.115890 ↗
13. Effects and improvements of different reagents preservation methods on the determination of phosphate in seawater by phosphomolybdenum blue spectrophotometric method10.1016/j.marpolbul.2018.12.011 ↗
14. Limitations of the molybdenum blue method for phosphate quantification in the presence of organophosphonates10.1007/s00216-025-05850-y ↗
15. Li, H., Song, Y., Zhou, B., and Xu, H. (2024). Nitrite: From Application to Detection and Development. Appl. Sci., 14.10.3390/app14199027 ↗
16. Niu, W., Li, H., Guo, X., Chen, J., Shi, X., and Zhu, Y. (2023). Field determination of nitrate in seawater using a novel on-line coppered cadmium column: A comparison study with the vanadium reduction method. Front. Mar. Sci., 10.10.3389/fmars.2023.1138734 ↗
17. Li, D., Xu, S., Jin, H., Wang, J., and Yan, F. (2023). Copper Nanoparticles Confined in a Silica Nanochannel Film for the Electrochemical Detection of Nitrate Ions in Water Samples. Molecules, 28.10.3390/molecules28227515 ↗
18. Zhu, X., Yu, K., Zhu, X., Su, J., and Wu, C. (2021). An Improved Algorithm for Measuring Nitrate Concentrations in Seawater Based on Deep-Ultraviolet Spectrophotometry: A Case Study of the Aoshan Bay Seawater and Western Pacific Seawater. Sensors, 21.10.3390/s21030965 ↗
19. Hourly In Situ Nitrate on a Coastal Mooring: A 15-Year Record and Insights into New Production10.5670/oceanog.2017.428 ↗
20. In situ real-time monitoring of ammonium, potassium, chloride and nitrate in small and medium-sized rivers using ion-selective-electrodes—A case study of feasibility10.1039/D5VA00021A ↗
21. Jacobs, S.R., Weeser, B.R., Rufino, M.C., and Breuer, L. (2020). Diurnal Patterns in Solute Concentrations Measured with In Situ UV-Vis Sensors: Natural Fluctuations or Artefacts?. Sensors, 20.10.3390/s20030859 ↗
22. Altahan, M.F., Esposito, M., and Achterberg, E.P. (2022). Improvement of On-Site Sensor for Simultaneous Determination of Phosphate, Silicic Acid, Nitrate plus Nitrite in Seawater. Sensors, 22.10.3390/s22093479 ↗
23. Applications of Microfluidic Technology in Marine Analysis and Monitoring
24. Comparison of different continuous in-situ observation systems in seawater
25. Potential environmental impact of tidal energy extraction in the Pentland Firth at large spatial scales: Results of a biogeochemical model10.5194/bg-13-2593-2016 ↗
26. On-site detection of nitrate plus nitrite in natural water samples using smartphone-based detection10.1016/j.microc.2021.106117 ↗
27. Real-Time Underway Mapping of Nutrient Concentrations of Surface Seawater Using an Autonomous Flow Analyzer10.1021/acs.analchem.2c02000 ↗
28. Consecutive spectrophotometric determination of phosphate and silicate in a sequential injection lab-at-valve flow system10.1016/j.aca.2023.341464 ↗
29. Development of a simplified spectrophotometric method for nitrite determination in water samples10.1016/j.saa.2021.120574 ↗
30. A fast and direct spectrophotometric method for the sequential determination of nitrate and nitrite at low concentrations in small volumes10.1016/j.marchem.2014.03.002 ↗
31. Evolution of the fluorometric method for the measurement of ammonium/ammonia in natural waters: A review10.1016/j.trac.2024.117519 ↗
32. On Applicability of IQR Method for Filtering of Experimental Data10.1134/S1810232824010016 ↗
33. SAC (2025, August 12). The Specification for Marine Monitoring Part 2: Data Processing and Quality Control of Analysis. Standardization Administration of the People’s Republic of China, Available online: https://openstd.samr.gov.cn/bzgk/gb/newGbInfo?hcno=2A832569DF947259C8793864F584618F.