Development and Application of an Adaptable Attachment to Improve the Measurement Performance of Dissolved Oxygen Meters

Commercial dissolved oxygen (DO) meters are widely used across many research fields, yet their utility is often limited by large sample-volume requirements, an upper measurement range of ~50 mg/L, temperature constraints, and poor compatibility with non-aqueous liquids.Here, we present a low-cost, modular acrylic attachment consisting of a sealed measurement chamber and an interchangeable sensor connector that extends the operating envelope of conventional probe-type DO sensors.Deoxygenated water (5-6 mL) is generated in situ, a small aliquot of sample (50-500 μL) is injected, and an adjustable threaded lid minimizes headspace-driven oxygen contamination.Oxygen release is then quantified from the increase in aqueous DO following dilution and mixing.Using the attachment, measurements of air-and oxygen-saturated water closely matched direct DO readings (slope = 0.974), with