吞酸

folic acid

CITRIC ACID Monohydrate BP 93

L(+)tartaric acid

malic acid diethyl ester; diethyl malate

carboxylic acid esters from alcoholates and carboxylic acids

D-(-)-Tartaric acid

parahydroxyphenyl-propionic acid

PA610；PA from Hexamethylene diamine and Sebacic acid(DIN,ISO)