Table 1.

Number of lipid species detected by MALDI-MSI, MALDI-MS and ESI-LC-MS. These three MS methods detect different numbers of lipid species and classes (G=ganglioside). MALDI-MS and -MSI detects drastically different classes depending on instrument polarity. Lipids in most classes, especially the low abundance CL, are detected with progressively better refinement by these three MS methods. LC-MS is shown for negative mode only since the chromatographic conditions will detect species from all classes in that mode, while MALDI-MS and -MSI required both positive and negative mode for a comprehensive analysis.

	PC	PE	Cer	SM	G	ST	PG	PI	PS	PA	CL	Total
MALDI- MSI Positive mode	6	3	1	1	0	0	0	0	0	0	0	11
MALDI- MSI Negative mode	0	0	0	0	7	10	1	5	4	0	10	37
MALDI- MS extract Positive mode	6	5	1	2	0	0	0	0	0	0	0	14
MALDI-MS extract Negative mode	0	0	0	0	12	10	1	7	1	0	31	65
ESI-LC- MS	29	27	7	8	5	18	16	16	16	13	70	225