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Droplet microfluidic-based in situ analyzer for monitoring free nitrate in soil

Lu, B., Lunn, J., Yeung, K., Dhandapani, S. ORCID:, Carter, L., Roose, T., Shaw, L., Nightingale, A. and Niu, X. (2024) Droplet microfluidic-based in situ analyzer for monitoring free nitrate in soil. Environmental Science and Technology. ISSN 1520-5851

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To link to this item DOI: 10.1021/acs.est.3c08207


Monitoring nutrients in the soil can provide valuable information for understanding their spatiotemporal variability and informing precise soil management. Here, we describe an autonomous in situ analyzer for the real-time monitoring of nitrate in soil. The analyzer can sample soil nitrate using either microdialysis or ultrafiltration probes placed within the soil and quantify soil nitrate using droplet microfluidics and colorimetric measurement. Compared with traditional manual sampling and lab analysis, the analyzer features low reagent consumption (96 μL per measurement), low maintenance requirement (monthly), and high measurement frequency (2 or 4 measurements per day),providing nondrifting lab-quality data with errors of less than 10% using a microdialysis probe and 2−3% for ultrafiltration. The analyzer was deployed at both the campus garden and forest for different periods of time, being able to capture changes in free nitrate levels in response to manual perturbation by the addition of nitrate standard solutions and natural perturbation by rainfall events.

Item Type:Article
Divisions:Science > School of Archaeology, Geography and Environmental Science > Department of Geography and Environmental Science
ID Code:115116
Publisher:American Chemical Society


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