Table 1.

Example of routinely used external calibrants for lipid analysis through MALDI-IMS. 2,5-Dihydroxybenzoic acid (DHB), sinapinic acid (SA), α-cyano-4-hydroxycinnamic acid (CHCA), N-naphthylethylenediamine dihydrochloride (NEDC), 2’,4’,6’-trihydroxyacetophenone monohydrate (THAP), 1,5-diaminonaphthalene (DAN).

Study	External calibrants	Matrix	Tissue	Instrument
Kaya I. et. al.71	Red Phosphorus	Norharmane	Non-human primate coronal brain	MALDI-FTICR (SolariX, Bruker)
Angelini R. et al.78	Mixture of phosphatidylcholine and lysophosphatidylcholine	CHCA	Mouse brain	MALDI TOF/TOF (UltraFlextreme, Bruker)
Liang X. et al.76	Mixture of DHB, SA, CHCA, and peptides.	NEDC	Whole Zebrafish	MALDI-TOF/TOF (RapifleX, Bruker)
Tobias F. et al.72	Red Phosphorus	9AA (lipids) DHB (Cholesterol)	Mouse brain	MALDI TOF/TOF (Sciex)
Kaya I. et al.129	Mixture of standard peptides	DAN	Mouse brain	MALDI TOF/TOF (UltraFlextreme, Bruker)
Mallah K. et al.75	Mixture of standard peptides	DHB	Rat brain	MALDI-LTQ-Orbitrap-XL (Thermo Fisher Scientific)
Prentice BM. et al.73	Mixture of standard peptides for positive mode calibration and matrix clusters for negative mode calibration	DAN	Mouse brain	MALDI TOF/TOF In-house built
O’Rourke MB. et al.70	Red Phosphorus	DHB	Human brain	MALDI TOF/TOF (UltraFlextreme, Bruker)
Jackson SN. et al.77	Mixture of phosphatidylcholines and sphingomyelins	DHA	Rat brain	MALDI-TOF/TOF (Applied Biosystems)
Thomas A. et al.51	Lipid and peptide mixture	DAN	Mouse brain, liver Fish whole body	MALDI TOF/TOF (UltraFlextreme, Bruker)