Automated desorption electrospray ionization two-dimensional tandem mass spectrometry: Instrumentation and software for high throughput analysis

Abstract

Two-dimensional tandem mass spectrometry (2D-MS/MS) provides rapid unsupervised access to all product ions of all ionized precursor ions. In this study, desorption electrospray ionization is used to create ion populations from complex mixtures prior to the use of 2D MS/MS to characterize each sample in an array. Automated high-throughput examination of each sample in the array is achieved by integrating movement of the sample array with automated acquisition of data from each sample through a serial handshake procedure. Position control is achieved using an Arduino microprocessor, a RAMPS control board, two stepper motors, and a custom MATLAB graphical user interface. Data processing improvements to the 2D-MS/MS workflow included optimizing the contrast of the intensity distribution of individual precursor to product ion transitions in local regions of the 2D spectrum to enhance visual discrimination of peaks from the background. This study demonstrates the combination of several advanced capabilities for practical mass spectrometry including high throughput experiments on unmodified samples with unconstrained sample acquisition and fully automated instrumental control and data manipulation. These capabilities are demonstrated with several model mixtures spotted on a PTFE-coated substrate, where the total analysis time was 64 s. Details of the system and discussion of the system performance are provided.