Miniaturization of electrochemical cells for mass spectrometry

• Miniaturization enables the design of innovative electrochemical cells.
• Scaling down structure sizes enhances electrochemical-conversion performance.
• Integration on chip enables multiple steps to be carried out in a single device.
• New materials expand the functionality of microfluidic electrochemical cells.

The combination of electrochemistry (EC) and mass spectrometry (MS) (EC-MS) has proved to be powerful and versatile for important biological and chemical analyses, including the study of drug metabolism, the oxidation and the cleavage of proteins, and environmental research. The electrochemical-cell designs used in these studies are critical for the types of analyses that can be carried out using EC-MS instrumentation, and, to this end, miniaturization opens up a wide range of new possibilities. In this review, we identify the benefits associated with microfluidic electrochemical cells, and describe design and fabrication aspects of these devices. Next, we highlight the use of microfluidic electrochemical cells in EC-MS studies and specific trends in miniaturization that will expand the range of possible applications for these devices in EC-MS analysis.