E‑SCAN: Electrochemical Scanning of Carbonates, an In Situ Approach for Screening and Quantifying Inorganic Carbon in Soil

• Published in: Journal of agricultural and food chemistry Vol. 71; no. 43; pp. 15954 - 15962
• Main Authors: Dhamu, Vikram Narayanan, Muthukumar, Sriram, Prasad, Shalini
• Format: Journal Article
• Language: English
• Published: American Chemical Society 01-11-2023
• Subjects: Agricultural and Environmental Chemistry; mineral carbon; electrochemical impedance spectroscopy; soil sensor; carbon sequestration tracking; soil inorganic carbon; electrochemical sensor; soil carbon monitoring
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/acs.jafc.3c02948

A modified three-electrode system was utilized with a correlated ion-capture film that is functional to changes in soil carbonate moieties to determine an understudied pool of soil carbon that is vital toward holistic carbon sequestrationcarbonous soil minerals (CSM). This composite sensor was tested on soils with varying carbonate contents using cyclic voltammetry, chromatocoulometry (DC-based), and electrochemical impedance spectroscopy to determine signal output as a function of increasing dose. To determine the in-field capability, a portable potentiostat device was integrated into a probe head setup that could be inserted into soil for testing. The results from these experiments showed a linearity of R 2 > 0.97 and a measurable sensing range from 0.01% (100 ppm) to 1% (10 000 ppm). Therefore, a first-of-a-kind in-soil sensor system was developed for determining carbonate content in real soil samples using electrochemistry that can be tested in-field to survey the field-deployable and point-of-use capability of the system.