TY - JOUR

T1 - Coupling Droplet Microfluidics with Ion Mobility Spectrometry for Monitoring Chemical Conversions at Nanoliter Scale

AU - Hartner, Nora T.

AU - Wink, Konstantin

AU - Raddatz, Christian Robert

AU - Thoben, Christian

AU - Schirmer, Martin

AU - Zimmermann, Stefan

AU - Belder, Detlev

N1 - Funding Information: This work was funded by the Deutsche Forschungsgemeinschaft (DFG) Project numbers 396430937, 458829155, and FOR 2177. The authors also thank Carolina F. Costrino for her collaboration during the project.

PY - 2021/10/12

Y1 - 2021/10/12

N2 - We introduce the coupling of droplet microfluidics and ion mobility spectrometry (IMS) to address the challenges of label-free and chemical-specific detection of compounds in individual droplets. In analogy to the established use of mass spectrometry, droplet-IMS coupling can be also achieved via electrospray ionization but with significantly less instrumental effort. Because IMS instruments do not require high-vacuum systems, they are very compact, cost-effective, and robust, making them an ideal candidate as a chemical-specific end-of-line detector for segmented flow experiments. Herein, we demonstrate the successful coupling of droplet microfluidics with a custom-built high-resolution drift tube IMS system for monitoring chemical reactions in nL-sized droplets in an oil phase. The analytes contained in each droplet were assigned according to their characteristic ion mobility with limit of detections down to 200 nM to 1 μM and droplet frequencies ranging from 0.1 to 0.5 Hz. Using a custom sheath flow electrospray interface, we have further achieved the chemical-specific monitoring of a biochemical transformation catalyzed by a few hundred yeast cells, at single droplet level.

AB - We introduce the coupling of droplet microfluidics and ion mobility spectrometry (IMS) to address the challenges of label-free and chemical-specific detection of compounds in individual droplets. In analogy to the established use of mass spectrometry, droplet-IMS coupling can be also achieved via electrospray ionization but with significantly less instrumental effort. Because IMS instruments do not require high-vacuum systems, they are very compact, cost-effective, and robust, making them an ideal candidate as a chemical-specific end-of-line detector for segmented flow experiments. Herein, we demonstrate the successful coupling of droplet microfluidics with a custom-built high-resolution drift tube IMS system for monitoring chemical reactions in nL-sized droplets in an oil phase. The analytes contained in each droplet were assigned according to their characteristic ion mobility with limit of detections down to 200 nM to 1 μM and droplet frequencies ranging from 0.1 to 0.5 Hz. Using a custom sheath flow electrospray interface, we have further achieved the chemical-specific monitoring of a biochemical transformation catalyzed by a few hundred yeast cells, at single droplet level.

UR - http://www.scopus.com/inward/record.url?scp=85117188042&partnerID=8YFLogxK

U2 - 10.1021/acs.analchem.1c02883

DO - 10.1021/acs.analchem.1c02883

M3 - Article

AN - SCOPUS:85117188042

VL - 93

SP - 13615

EP - 13623

JO - Analytical chemistry

JF - Analytical chemistry

SN - 0003-2700

IS - 40

ER -