All-in-one portable microsystem for on-site electrochemical determination of phosphate in turbid coastal waters

The direct detection of phosphate in turbid coastal waters is important but difficult to achieve. Herein, we propose an effective and portable all-in-one microsystem for the electrochemical determination of phosphate in turbid coastal waters without adding additional reagents and requiring a pump filter device. The all-in-one portable microsystem is composed of a simple 3D-printed manufactured electrochemical sensor microsystem, a commercial micropipette, and a disposable molybdate-functionalized tip. It integrates the complexation step, in which non-electroactive phosphate is converted to a phosphomolybdate complex by a molybdate functionalized tip, and the detection step, in which a phosphomolybdate complex is reduced in an electrochemical sensor microsystem. The microsystem showed a low detection limit of 0.04 μM under optimized experimental conditions; one entire test cycle could be accomplished within 3 min. The proposed all-in-one portable microsystem was successfully used in a variety of real coastal water samples with high turbidity and high salinity. It represents a competitive alternative analytical tool and a novel approach for the assessment of turbid costal water quality.