Category: Automation and High-Throughput Technologies

1052-C - A New Platform for High-Throughput Mass Spectrometry: Acoustic Droplet Ejection with an Open Port Probe Sampling Interface.

Tuesday, February 6, 2018
2:00 PM - 3:00 PM

We demonstrate a system combining acoustic droplet ejection (ADE) with the open port probe sampling interface for high-throughput mass spectrometry (MS). 

The Labcyte Echo® ADE instrument is a robust platform that can eject 2.5 nL droplets from a fluid meniscus at high speed with excellent accuracy (< 10%) and precision (< 8% CV). The instrument can address a broad range of fluid classes utilizing Dynamic Fluid Analysis (DFA), a real-time auditing, sensing and calibration technology.

The open port probe (OPP) sampling interface is a simple, versatile and self-cleaning system for rapidly introducing multiple types of unprocessed samples into a solvent flow stream for subsequent ionization and analysis by ESI mass spectrometry.  This interface uses co-axial tubes arranged to deliver solvent to the sampling end of the device through the tubing annulus and then aspirate by the Venturi effect of the nebulizer gas through the center tube for delivery into the mass spectrometer ionization source.

When the ADE and OPP are combined, the Labcyte Echo® ADE instrument delivers droplets from a microplate into a continuous flow OPP oriented in an inverted configuration to receive the vertically ejected droplets from the well plate.  The OPP fluid stream is aspirated into the MS electrode where sample is ionized by standard electrospray prior to entering a Sciex 5500 QTrap mass spectrometer.  This approach decouples the sample delivery and ionization processes.

A precision solvent delivery pump allows us to explore the solvent flow rate effects on peak width and intensity.  We tested a range of pump flow rates relative to the fixed aspiration rate, going from balanced flow rates with a small solvent vortex to unbalanced flows with a hanging droplet of solvent.  The flow rate stability of our pump provided good reproducibility and peak shape and allows us to generate calibration curves with excellent linearity.  Initial results are described for reserpine in a methanol solvent.

Luke P. Ghislain

Senior Staff Engineer
Labcyte Inc
San Jose, CA

Exploring nascent opportunities at the intersection of technologies for molecular sensing and small sample processing.

Responsible for creating new acoustic dispensing capabilities. Over twenty years of experience in both industry & academia with emphasis on instrumentation for microscopy.