Lipid geographical analysis of the primate macula by imaging mass spectrometry

Imaging mass spectrometry (IMS) provides a unique method to probe for chemical distributions within tissue sections with high chemical specificity. The direct analysis of tissue sections by mass spectrometry, which is the field of IMS, is relatively young, 10 year old; however, the techniques for mass spectrometric analysis are well known. Critical aspects of IMS then are the preparation of tissue specimens for insertion into a vacuum chamber and the interpretation of results with respect to disease studies. Here, we describe the methodologies for geographic localization of phospholipids in flat-mounted eye segments from rhesus monkey using IMS with matrix-assisted laser desorption/ionization (MALDI) and tandem mass spectrometry.