Table 1. Matrices or matrix additives reported in this review.

Name (abbreviation)	Structure	Matrix/Matrix additive (novel/reported)	Analytes (in the ref.)	Characteristics/Applications	Ref.
For glycopeptides, carbohydrates, phosphopeptides
2,5-DHB		Solid matrix (reported)	Glycopeptides	Rapid analyses of glycopeptides by MSn of the [M+Na]+ and [M+H]+.	29
G3CA		Liquid matrix (novel)	Glycopeptides, carbohydrates	High sensitive analyses and suppression of dissociation for labile regions such as sulfate groups and sialic acids of carbohydrates from a homogeneous matrix-analyte spot.	12
3-AQ/CHCA		Liquid matrix (reported)	Phosphopeptides	High sensitive analyses of phosphopeptides by optimized preparation methods on a MALDI focusing plate using the matrix.	13
3-AQ/CA		Liquid matrix (novel)	Glycopeptides, carbohydrates, phosphopeptides	High sensitive analyses and suppression of dissociation for labile regions such as phosphate groups and sialic acids on a MALDI focusing plate.	14
For general peptides, peptides containing disulfide bonds, hydrophobic peptides
CHCAB		Ionic liquid matrix (reported)	Peptides	High sensitive and reproducible (spot-to-spot and shot-to-shot) analyses from homogeneous matrix-analyte spot by adding methanol on a MALDI focusing plate.	15
1,5-DAN		Solid matrix (reported)	Peptides containing disulfide bonds	Rapid sequencing by reduction reaction of disulfide bonds.	30
ADHB		Solid matrix additive (novel)	Hydrophobic peptides	High sensitive analyses by enrichment of hydrophobic peptides in the rim of a matrix-analyte spot.	31, 32
ATHAP		Solid matrix (novel)	Hydrophobic peptides	High sensitive analyses and preferential ionization of hydrophobic peptides from a homogeneous matrix-analyte spot.	33