TY - JOUR
T1 - Development of microfluidic droplet shooter and its application to interface for mass spectrometry
AU - Kazoe, Yutaka
AU - Shimizu, Yusuke
AU - Morikawa, Kyojiro
AU - Terui, Yasushi
AU - Irie, Takashi
AU - Kitamori, Takehiko
N1 - Funding Information:
The authors would like to thank Mr. Taku Sakazume, Mr. Kimiyoshi Koda and Ms. Yoshiko Ishida from Hitachi High-Tech Corporation, and Prof. Emer. Shigeru Terabe from the University of Hyogo for fruitful discussion. The authors gratefully acknowledge the financial support from the Social Cooperation Program on Next-generation Analytical Instrumentation between the School of Engineering at the University of Tokyo and Hitachi High-Tech Corporation. Some of the fabrication facilities were provided by the Academic Consortium for Nano and Micro Fabrication by four universities (Keio University, Waseda University, Tokyo Institute of Technology, and the University of Tokyo, Japan).
Funding Information:
The authors would like to thank Mr. Taku Sakazume, Mr. Kimiyoshi Koda and Ms. Yoshiko Ishida from Hitachi High-Tech Corporation, and Prof. Emer. Shigeru Terabe from the University of Hyogo for fruitful discussion. The authors gratefully acknowledge the financial support from the Social Cooperation Program on Next-generation Analytical Instrumentation between the School of Engineering at the University of Tokyo and Hitachi High-Tech Corporation. Some of the fabrication facilities were provided by the Academic Consortium for Nano and Micro Fabrication by four universities (Keio University, Waseda University, Tokyo Institute of Technology, and the University of Tokyo, Japan).
Publisher Copyright:
© 2021 Elsevier B.V.
PY - 2021/8/1
Y1 - 2021/8/1
N2 - Gas/liquid microfluidics has developed for high-efficiency mass transport, mixing and reaction in various applications of chemical analysis and synthesis. However, ejection of uniform liquid droplets floating in gas phase from the microchannels with trajectory control is still challenging. In this study, we developed a method for shooting picoliter droplets in a controlled direction that utilizes microscale gas-phase laminar flows and applied it to a mass spectrometry (MS) interface. The principle of droplet shooting using two-step gas-phase flow focusing was proposed. A microfluidic device with a branched and stepped hydrophobic microchannel was fabricated by top-down glass fabrication technologies. We verified the shooting of droplets of aqueous and organic solvents in the volume range of 3.61–24.9 pL at kilohertz frequencies. A model that considers the capillary force and the drag force was verified to establish a design guideline. Utilizing the developed microfluidic droplet shooter, we demonstrated high-efficiency sample transport to a single quadrupole mass spectrometer. We verified a sample injection rate of approximately 100 % by ejection of picoliter droplets into an MS injection aperture of a 400-μm diameter and achieved detection of caffeine with 3 times higher sensitivity than conventional electrospray ionization interface with sample dispersion.
AB - Gas/liquid microfluidics has developed for high-efficiency mass transport, mixing and reaction in various applications of chemical analysis and synthesis. However, ejection of uniform liquid droplets floating in gas phase from the microchannels with trajectory control is still challenging. In this study, we developed a method for shooting picoliter droplets in a controlled direction that utilizes microscale gas-phase laminar flows and applied it to a mass spectrometry (MS) interface. The principle of droplet shooting using two-step gas-phase flow focusing was proposed. A microfluidic device with a branched and stepped hydrophobic microchannel was fabricated by top-down glass fabrication technologies. We verified the shooting of droplets of aqueous and organic solvents in the volume range of 3.61–24.9 pL at kilohertz frequencies. A model that considers the capillary force and the drag force was verified to establish a design guideline. Utilizing the developed microfluidic droplet shooter, we demonstrated high-efficiency sample transport to a single quadrupole mass spectrometer. We verified a sample injection rate of approximately 100 % by ejection of picoliter droplets into an MS injection aperture of a 400-μm diameter and achieved detection of caffeine with 3 times higher sensitivity than conventional electrospray ionization interface with sample dispersion.
KW - Droplet microfluidics
KW - Droplet shooting
KW - Gas-liquid
KW - Mass spectrometry
KW - Microchannel
UR - http://www.scopus.com/inward/record.url?scp=85104398812&partnerID=8YFLogxK
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U2 - 10.1016/j.snb.2021.129957
DO - 10.1016/j.snb.2021.129957
M3 - Article
AN - SCOPUS:85104398812
VL - 340
JO - Sensors and Actuators, B: Chemical
JF - Sensors and Actuators, B: Chemical
SN - 0925-4005
M1 - 129957
ER -