A paper-based screen-printed electrochemical sensor combined with a 3D printed extracting cartridge for analysis of phosphorus in Antarctic lacustrine sediments

Here, we present a novel fully printed electrochemical sensing tool for determining phosphorus levels in sediment samples. The integrated electrochemical device is composed of an office paper-based sensor combined with a customized 3D printing cube-shaped holder used for the extraction of phosphorus from sediment samples. The extracted phosphorus was trapped on a filter pad placed over the sensor and preloaded with acidic ammonium molybdate, allowing for the formation of the phosphomolybdate complex, which is electroactive. The use of carbon black as a nanomodifier of office paper-based electrode together with square wave voltammetry enabled the detection of phosphorus with a detection limit of 0.011 ppm within a broad linear range of 0.039-20 ppm. Furthermore, this sensor demonstrated excellent selectivity towards phosphate ions among the several ions studied, namely NO₃^-, NO₂^-, F^-, SO₄^2-, CH₃COO^-, Cl^-, CO₂^3-, Mg²⁺, K⁺, Zn²⁺, Ca²⁺, Na⁺, Cu²⁺, and Ni²⁺. The precision of the analytical platform was evaluated using eight distinct sensors, yielding a relative standard deviation below 5 %. The reliability of the paper-based integrated sensor was assessed by determining phosphorus levels in sediment samples obtained from various seasonal shallow coastal lakes situated in Northern Victoria Land, Antarctica, by comparing the data obtained with both the novel printed integrated device and the colorimetric reference method. The agreement of the data with a coefficient of correlation equal to 0.86 (r = 0.86) demonstrated the great potential of the developed sensing tool for use in real-world applications.