INFRARED MATRIX-ASSISTED LASER DESORPTION ELECTROSPRAY IONIZATION (ir-maldesi) IMAGing source Coupled to a FT-ICR mass spectrometer
Guillaume Robichaud1, Jeremy A. Barry1, Kenneth P. Garrard2 and David C. Muddiman1*
1W.M. Keck FT-ICR Mass Spectrometry Laboratory, Department of Chemistry,
North Carolina State University, Raleigh, North Carolina 27695
2Precision Engineering Center, North Carolina State University, Campus Box 7918, Raleigh, North Carolina 27695
Submitted to:
Journal of the American Society for Mass Spectrometry
Submitted : August 14, 2012
Revised : September 14, 2012
Supplementary Material :7 Pages / 6 Figures / 0 Tables
Running Title: IR-MALDESI imaging
*Author for Correspondence
David C. Muddiman, Ph.D.
W.M. Keck FT-ICR Mass Spectrometry Laboratory
Department of Chemistry
North Carolina State University
Raleigh, North Carolina 27695
Phone: 919-513-0084
Fax: 919-513-7993
Email:
Figure S1. Scan Control GUI window programmed with MATLAB. The user friendly interface allow the selection of all scanning parameters, including the selection of the region of interest using overhead camera.
Figure S2.Calibration of laser position/camera field of view (FOV) offset with reference to region of interest (ROI). This allows both the overhead camera and laser beam to be aimed normal to the sampling plane. Three steps are : A) Laser is shot near sample and position is recorded by software. B) Camera is moved to camera FOV position, laser marker is dragged over the laser spot burn mark and ROI is defined. C) Offset between the laser position and the ROI is taken into account when raster program is generated automatically from user parameters.
Figure S3.Simple signal delay generator to trigger Q-Switched laser by a fixed delay after the flashlamp fire signal. Delay can be adjusted with a microsecond resolution. Uses 2 x 555 timers, an inverter IC and standard resistors, potentiometers, capacitors and diodes.
Figure S4.Schematics of IR-MALDESI Imaging Control box containing an Arduino open source board and a delay generator (see picture on S3). Parts outside of dashed lines are interconnects to peripherals.
Figure S5. MS imaging control box and interconnectfrom schematics presented in Figure S4 showing the Arduinomicrocontroller, the trigger delay board (detailed in Figure S3) and interconnect.
Figure S6.Snapshot ofMSiReader interface. Bruker’s .ascii file or .mzXML file is loaded and user can explore image file with no limitation on m/z and abundance resolution other than the ones from the original instrument file. Heat map can be customized and figures saved to be used in publication and presentations.