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Laboratory-determined Phosphorus Flux from Lake Sediments as a Measure of Internal Phosphorus Loading
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A submersible phosphate analyzer for marine environments based on inlaid microfluidics
Sean Morgan1, Edward Luy2, Arnold Furlong2
1Department of Electrical and Computer Engineering, Dalhousie University, 1360 Barrington Street, Halifax, Nova Scotia, B3H 4R2, Canada. sieben@dal.ca.
Analytical Methods : Advancing Methods and Applications
|December 7, 2021
Summary
A new automated sensor accurately measures marine phosphate levels using microfluidic technology. This innovation aids in understanding short-term nutrient changes in seawater, crucial for environmental monitoring.
Area of Science:
- Environmental Science
- Analytical Chemistry
- Oceanography
Background:
- Understanding phosphate flux dynamics in marine environments is critical for monitoring short-term events like tidal cycles and algal blooms.
- Existing methods for measuring phosphate in situ are limited, necessitating the development of advanced sensor technologies.
Purpose of the Study:
- To develop and validate a fully automated in situ phosphate analyzer for marine environments.
- To assess the sensor's performance and viability in observing nanomolar variations in nutrient flux.
Main Methods:
- Development of an automated in situ phosphate analyzer utilizing microfluidic absorbance cell technology.
- Employing colorimetric absorbance spectrophotometry with the phosphomolybdenum blue (PMB) assay and polyvinylpyrrolidone (PVP).
- Benchtop calibrations, temperature sensitivity studies, and two field deployments for performance assessment and cross-validation.
Main Results:
- The sensor achieved a limit of detection of 15.2 nM and a limit of quantification of 50.8 nM.
- Demonstrated high in situ precision with a relative standard deviation of less than 1.5% for consecutive measurements.
- Successfully acquired over 300 measurements in field deployments, revealing tidal cycle influences and confirming viability for nutrient flux dynamics.
Conclusions:
- The developed automated in situ phosphate sensor is a viable tool for observing nutrient flux dynamics in marine environments.
- The sensor's ability to detect nanomolar variations makes it suitable for studying short-term oceanic events.
- This technology advances in situ monitoring capabilities for marine phosphate concentrations.
