A novel analytical approach for the simultaneous measurement of nitrate and dissolved organic carbon in soil water

Abstract

Abstract. In this paper, we present a novel approach, enabling the measurement of nitrate concentrations in natural soil porewater containing natural soil dissolved organic carbon (DOC). The method is based on UV absorbance spectroscopy, combined with fluorescence spectroscopy, for simultaneous analysis of DOC and nitrate concentrations. The analytical procedure involves deduction of the absorption caused by the DOC from the total absorbance in the UV range that is attributed to both DOC and nitrate in the water solution. The analytical concept has been successfully tested in soil water samples obtained from five agricultural sites, as well as in water samples obtained from a commercial humus soil mixture. We believe that the new analytical concept can provide a scientific foundation for developing a sensor for real-time nitrate concentration measurements in agricultural soils. As such, it can play a significant role in reducing nitrate pollution in water resources, optimizing input application in agriculture, and decreasing food production costs.

Aqueous-phase photochemical oxidation of water-soluble brown carbon aerosols arising from solid biomass fuel burning

“…Although the spectrophotometer can measure absorbances from 325 to 1100 nm, only 330 to 700 nm absorbance data were utilized in this study to minimize matrix interference from compounds such as nitrates, which absorb at wavelengths < 340 nm. 3,54 These absorbance measurements were further utilized to calculate absorption properties, specifically, mass absorption efficiency (MAE WS-BrC- λ ) and solar-weighted total absorbance for WS-BrC from 330 to 500 nm. The MAE of WS-BrC, expressed in m 2 g −1 -C, at a given wavelength (MAE WS-BrC- λ ) was calculated using eqn (1) 19 where A WS-BrC- λ is the absorbance of WS-BrC at a given wavelength ( λ ), l is the path length of the spectrophotometer ( i.e.…”

Advances in Catchment Science, Hydrochemistry, and Aquatic Ecology Enabled by High-Frequency Water Quality Measurements

“…High-frequency water quality sensors are part of the greater “high-frequency wave of the present” 10 in which high-frequency measurements of key elements, e.g., C, N, and P, are becoming readily available for different environments and media such as gases, 197 soils, 198 and biological samples with environmental DNA. 199 Ultimately, using multisensor technologies simultaneously to measure key biogeochemical cycles across Earth subsystems (i.e., atmosphere, soils, waters, biosphere) can lead to new discoveries of elemental and ecosystem interactions and fundamentally improve our estimates of fluxes and turnover rates from river networks.…”