Details

Autor(en) / Beteiligte

• Wilder, Logan M
• Thompson, Jonathan R
• Crooks, Richard M

Titel

Electrochemical pH regulation in droplet microfluidics

Ist Teil von

• Lab on a chip, 2022-02, Vol.22 (3), p.632-64

Ort / Verlag

England: Royal Society of Chemistry

Erscheinungsjahr

2022

Quelle

MEDLINE

Beschreibungen/Notizen

• We report a method for electrochemical pH regulation in microdroplets generated in a microfluidic device. The key finding is that controlled quantities of reagents can be generated electrochemically in moving microdroplets confined within a microfluidic channel. Additionally, products generated at the anode and cathode can be isolated within descendant microdroplets. Specifically, ∼5 nL water-in-oil microdroplets are produced at a T-junction and then later split into two descendant droplets. During splitting, floor-patterned microelectrodes drive water electrolysis within the aqueous microdroplets to produce H + and OH − . This results in a change in the pHs of the descendant droplets. The droplet pH can be regulated over a range of 5.9 to 7.7 by injecting controlled amounts of charge into the droplets. When the injected charge is between −6.3 and 54.5 nC nL −1 , the measured pH of the resulting droplets is within ±0.1 pH units of that predicted based on the magnitude of the injected charge. This technique can likely be adapted to electrogeneration of other reagents within microdroplets. The pH of droplets moving through a microchannel is regulated in real time by water electrolysis. Resulting droplet pHs are within ±0.1 pH units of the predicted values.