Title :
Towards on-chip chemical reaction monitoring by EWOD impedance measurement
Author :
Xiaoxiao Ma ; Supin Chen ; Kim, Chang-Jin Cj ; van Dam, R. Michael
Author_Institution :
Dept. of Mol. & Med. Pharmacology, Univ. of California, Los Angeles, Los Angeles, CA, USA
Abstract :
This paper demonstrates the use of impedance sensing in an electrowetting-on-dielectric (EWOD) chip to monitor the progress of a chemical reaction. Sensing is achieved by measuring the current through a sample droplet with the aid of a lock-in amplifier. Monitoring of the reaction of HCl with NaOH (i.e., during a titration) was demonstrated. A sharp minimum in the impedance signal was observed at the titration equivalence point, enabling the endpoint to be determined electronically. Future work is aimed at extending reaction monitoring to additional acid-base systems and other classes of reactions.
Keywords :
amplifiers; electric current measurement; electric impedance measurement; microprocessor chips; wetting; EWOD chip; acid-base systems; chemical reaction monitoring; current measurement; electrowetting-on-dielectric chip; equivalence point; impedance measurement; impedance sensing; impedance signal; lock-in amplifier; sample droplet; titration; Chemicals; Conductivity; Electrodes; Impedance; Impedance measurement; Monitoring; Sensors;
Conference_Titel :
Micro Electro Mechanical Systems (MEMS), 2014 IEEE 27th International Conference on
Conference_Location :
San Francisco, CA
DOI :
10.1109/MEMSYS.2014.6765645