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Here, we developed a microfluidic electrochemical flow cell for fast-scan cyclic voltammetry which is capable of rapid on-chip dilution for efficient and cost-effective electrode calibration. Fast-scan cyclic voltammetry (FSCV) at carbon-fiber microelectrodes is a robust electroanalytical technique used to measure subsecond changes in neurotransmitter concentration over time.Traditional methods of electrode calibration for FSCV require several milliliters of a standard. Additionally, generating calibration curves can be time-consuming because separate solutions must be prepared for each concentration. Microfluidic electrochemical flow cells have been developed in the past; however, they often require incorporating the electrode in the device, making it difficult to remove for testing in biological tissues. Likewise, current microfluidic electrochemical flow cells are not capable of rapid on-chip dilution to eliminate the requirement of making multiple solutions. We designed a T-channel device, with microchannel dimensions of 100 μm × 50 μm, that delivered a standard to a 2-mm-diameter open electrode sampling well. A waste channel with the same dimensions was designed perpendicular to the well to flush and remove the standard. The dimensions of the T-microchannels and flow rates were chosen to facilitate complete mixing in the delivery channel prior to reaching the electrode. The degree of mixing was computationally modeled using COMSOL and was quantitatively assessed in the device using both colored dyes and electrochemical detection. On-chip electrode calibration for dopamine with FSCV was not significantly different than the traditional calibration method demonstrating its utility for FSCV calibration. Overall, this device improves the efficiency and ease of electrode calibration. 

Polyaromatic hydrocarbons are central molecules in the future of nanotechnology. However, the synthesis of these molecules is limited by their lack of solubility in solvents, especially green solvents, their ease of oxidation in solution and use of harmful reagents. Solvent-free mechanochemistry has been shown to have excellent potential for these types of molecules and should provide a much more environmentally benign approach for the synthesis of this very important class of molecules. This report details the use of mechanochemistry on an iterative strategy for the synthesis of polyaromatic hydrocarbon derivatives.