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

A sensor for the determination of orthophosphate (PO 4 3- ) concentration in water was developed that utilizes the enzymatic cleavage of maltose in the presence of PO 4 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/PO 4 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 PO 4 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 PO 4 3- in tap and river water samples.