Table 1.

Folate standards used in this study (all purchased from Schircks Laboratories, Jona, Switzerland).

Standard	Abbreviated name	Formula
Pteroic acid	Pteroic acid	C14H12N6O3
p-aminobenzoyl-L-glutamate	pABGlu	C12H14N2O5
Folic acid	PteGlu	C19H19N7O6
7,8-dihydrofolic acid	H2PteGlu (DHF)	C19H21N7O6
(6R,S)-5,6,7,8-tetrahydrofolic acid	H4PteGlu (THF)	C19H23N7O6
(6R,S)-5,10-methenyl-5,6,7,8-tetrahydrofolic acid	5,10-CH=H4PteGlu	C20H21N7O6
(6R,S)-5,10-methylene-5,6,7,8-tetrahydrofolic acid	5,10-CH2-H4PteGlu	C20H23N7O6
(6S)-5-methyl-5,6,7,8-tetrahydrofolic acid	5-CH3-H4PteGlu (MTHF)	C20H25N7O6
(6S)-5-formyl-5,6,7,8-tetradrofolic acid	5-CHO-H4PteGlu	C20H23N7O7
(6R,S)-5-methyl-5,6,7,8-tetrahydropteroyldi-γ-L- glutamate	5-CH3-H4PteGlu2	C25H32N8O9
(6R,S)-5-formyl-5,6,7,8-tetrahydropteroyldi-γ-L- glutamate	5-CHO-H4PteGlu2	C25H30N8O10
p-aminobenzyltri-γ-L-glutamate	pABGlu3	C22H28N4O11
folic acid triglutamate	PteGlu3	C29H33N9O12
(6R,S)-5-methyl-5,6,7,8-tetrahydropteroyltri-γ-L- glutamate	5-CH3-H4PteGlu3	C30H39N9O12
(6R,S)-5-formyl-5,6,7,8-tetrahydropteroyltri-γ-L- glutamate	5-CHO-H4PteGlu3	C30H37N9O12
(6R,S)-5-methyl-5,6,7,8-tetrahydropteroyltetra-γ-L- glutamate	5-CH3-H4PteGlu4	C35H46N10O15
(6R,S)-5-formyl-5,6,7,8-tetrahydropteroyltetra-γ-L- glutamate	5-CHO-H4PteGlu4	C35H44N10O16
p-aminobenzylpenta-γ-L-glutamate	pABGlu5	C32H42N6O17
(6R,S)-5-methyl-5,6,7,8-tetrahydropteroylpenta-γ-L- glutamate	5-CH3-H4PteGlu5	C40H53N11O18
(6R,S)-5-formyl-5,6,7,8-tetrahydropteroylpenta-γ-L- glutamate	5-CHO-H4PteGlu5	C40H51N11O19
p-aminobenzylhepta-γ-L-glutamate	pABGlu7	C42H56N8O23