(1159-D) Advancing Acoustic Ejection Mass Spectrometry: Next-generation platform for high-throughput sample analysis

Abstract: The speed of sample analysis has become a key bottleneck in the drug discovery process. Typically, fluorescent labels are added to molecules of interest or potential new drug candidates for detection and quantitation purposes using plate readers that increase the cost per sample to analyze. Alternative approaches to high-throughput (HT) sample analysis implement mass spectrometry, which enables the label-free detection of the analyte via the mass-to-charge ratio. However, traditional LC-MS analysis requires minutes or hours to analyze samples, whereas traditional plate readers can achieve the necessary characterization in seconds.

This presentation describes the use of a prototype mass spectrometer capable of Acoustic Ejection Mass Spectrometry (AEMS) for the analysis of intact protein and small molecules. The prototype system uses an alternative approach to rapidly analyze molecules and solve some challenges faced by traditional techniques described above. Liquid samples are pipetted into 384- or 1536-well microtiter plates held by the system and acoustic energy is applied to the bottom of the well plate, causing a nanoliter-sized droplet of the sample to be ejected. The Open Port Interface (OPI) is located above the well plate and captures the ejected droplet for dilution and transport by a carrier solvent (~400 µL/min) of the diluted sample to an electrospray ionization source for ionization and delivery of diluted sample ions to a prototype high-resolution mass spectrometer for analysis.

This study explores important parameters (for example, carrier solvent composition, chemical additives and varying matrices) and system modifications that affect data quality of high-resolution AEMS on a high-throughput scale for robust and reliable system performance in biologically relevant buffers. Preliminary data show that implementing a modification to the OPI allows for a greater than 3x increase in the number of plates analyzed without a degradation of peak performance, thus increasing the robustness of the system. The acoustic ejection profiles have been updated to accommodate the versatility of the platform (for example, increasing the number of MRMs per sample). Samples were prepared using various concentrations and buffers with a Beckman Coulter® Biomek i7 liquid handler to create assay-ready plates. The preliminary AEMS data demonstrate the rapid analysis of compounds, as a 384-well plate can be analyzed in 10-30 minutes (1-5 seconds/sample) over a variety of mass spectrometry experiment types.