Development of a standard reticle target for calibration of MALDI imaging mass spectrometry instruments

Abstract

I describe a methodology for preparing and using a standard target for calibrating, laser alignment and focusing of MALDI imaging mass spectrometry instruments. The target is constructed by simple detachment patterning of a sublimed rubrene layer on an ITO glass slide. This pattern enables the measurement of the effective laser spot size as well as the accuracy of the raster step size at scale of 2 µm and larger for selected instrument settings. The use of the target is demonstrated on two MALDI TOF instruments, a highly modified Applied Biosystems 4700 instrument with an effective laser spot size of 2.5 µm and a commercial UltrafleXtreme with a laser spot size of 20-40 µm.