Orthophosphate Quantification in Water Utilizing an Enzymatic Reaction and a Commercial Glucometer Test Strip

A sensor for the determination of orthophosphate (PO4 3–) concentration in water was developed that utilizes the enzymatic cleavage of maltose in the presence of PO4 3– to generate an equivalent amount of glucose. The glucose produced from this reaction was quantified using a commercial glucometer test strip coupled to a miniature potentiostat using amperometry. This sensing approach yielded a limit of detection of 1.45 μM (0.1 ppm) glucose/PO4 3–, which is lower than that of a commercial glucometer (≥600 μM glucose), and a dynamic range of 10 μM–3 mM. The selectivity of the approach to PO4 3– was evaluated by determining the device’s response to known components in natural water samples. Finally, we showed that the approach can be used to determine PO4 3– in tap and river water samples.