Anoxic environments provide a challenge for measuring dissolved oxygen concentration. Currently, the only commercially available method that has sufficient sensitivity to quantify the dissolved oxygen concentration in anoxic waters (&lt; 1% oxygen saturation) is the STOX Electrode. Using a three-dimensional design, we have developed a microfluidic device for measuring low levels of dissolved oxygen. The device is fabricated using a sacrificial magnesium wire to form a channel through PDMS, which allows the electrodes to be exposed to solution. Rather than relying on simple diffusion to move oxygen through the channel, two driving electrodes and magnets create a magnetohydrodynamic flow to bring dissolved oxygen to the electrodes. Two guard electrodes alternate between reducing and unreactive potentials. At a reducing potential oxygen is consumed before it reaches the working electrode, allowing us to subtract noise. All nine electrodes (two driving, one working, two guard, two reference, two counters) are embedded in PDMS, which ensures the device is sufficiently robust for onsite analysis.

Microfluidic device for oxygen quantitation in anoxic environments

2019 Fall National Meeting

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