Quantitation of vitamin K in human milk.
A quantitative method was developed for the assay of vitamin K in human colostrum and milk. The procedure combines preparative and analytical chromatography on silica gel in a nitrogen atmosphere followed by reversed phase high performance liquid chromatography (HPLC). Two HPLC steps were used: gradient separation with ultraviolet (UV) detection followed by isocratic separation detected electrochemically. Due to co-migrating impurities, UV detection alone is insufficient for identification of vitamin K. Exogenous vitamin K was shown to equilibrate with endogenous vitamin K in the samples. A statistical method was incorporated to control for experimental variability. Vitamin K1 was analyzed in 16 pooled milk samples from 7 donors and in individual samples from 15 donors at 1 month post-partum. Vitamin K1 was present at 2.94 +/- 1.94 and 3.15 +/- 2.87 ng/mL in pools and in individuals, respectively. Menaquinones, the bacterial form of the vitamin, were not detected. The significance of experimental variation to studies of vitamin K in individuals is discussed.
Canfield
L M
LM
Department of Biochemistry, University of Arizona, Tucson 85721.
Hopkinson
J M
JM
Lima
A F
AF
Martin
G S
GS
Sugimoto
K
K
Burr
J
J
Clark
L
L
McGee
D L
DL
D000328:Adult; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid; D005260:Female; D006801:Humans; D008895:Milk, Human / Q000032:analysis*; D011786:Quality Control; D015203:Reproducibility of Results; D012588:Scintillation Counting; D013048:Specimen Handling; D014812:Vitamin K / Q000032:analysis* / Q000302:isolation & purification
D014812:Vitamin K