A pH Sensing Pipette for Cross-Contamination Prevention in Industrial Fermentation

The iconic pipette is integrated with an electrochemical pH sensor for preventing cross-contamination while still enabling pH measurements in industrial fermentation reactors. Contamination is a big financial cost source of the fermentation industry and periodic parameter (such as pH, dissolved oxygen, temperature, etc.) measurements are crucial for a successful fermentation run. Yet, the very act of measuring poses contamination risks to the fermentation reactors. To resolve the dichotomy between the need for pH monitoring and cross-contamination prevention, we develop a pH sensing pipette (composed of an integrated electrochemical polyaniline-based pH sensitive electrode, flowcell, and readout circuit) with a disposable pipette tip for cross-contamination-free pH measurements. This pH sensing pipette achieves a system-level sensitivity of -134.8 mV/pH, a limit of detection of pH 0.029 × 10-3, and an average response time of 2.6-6.0 s, which is good enough for pH measurements in industrial fermentation reactors. It is then demonstrated to monitor the pH of ethanol fermentation across two days successfully, implying that this device may be used to further prevent cross-contamination risks in industrial fermentation processes.